Group items tagged

Far more important than the SUVmax is the pattern rather than intensity of metabolic abnormality and the correlative CT findings

Descriptively, we define SUV < 5 as “low intensity”, 5–10 as “moderate”, 10–15 as “intense” and >15 as “very intense”

Evolving literature suggests that intensity of uptake is an independent prognostic factor and in some tumour subtypes superior to histopathologic characterisation.

aerobic glycolysis

Our practice of thresholding the grey and colour scale to liver as detailed above results in similar image intensity to a fixed upper SUV threshold of 8 to 10

The advantage of using the liver as a reference tissue is also aided by this organ having rather low variability in metabolic activity

When the liver is abnormal and cannot be used as a reference organ, we use the default SUV setting of an upper SUV threshold of 8

One of the most challenging aspects of oncologic FDG PET/CT review, however, is to recognise all the patterns of metabolic activity that are not malignant and which consequently confound interpretation

Many benign and inflammatory processes are also associated with high glycolytic activity

Future articles in the “How I Read” series will address the specific details of reading PET/CT in various cancers

The intensity of uptake in metastases usually parallels that in the primary site of disease

For example, discordant low-grade activity in an enlarged lymph node in the setting of intense uptake in the primary tumour suggests it is unlikely malignant and more likely inflammatory or reactive

By CT criteria the enlarged node is ‘pathologic’ but the discordantly low metabolic signature further characterises this is as non-malignant since such a node is not subject to partial volume effects and therefore the intensity of uptake should be similar to the primary site

The exception is when the lymph node is centrally necrotic as a small rim of viable tumour is subject to partial volume effects with expectant lower intensity of uptake; integrating the CT morphology is therefore critical to reaching an accurate interpretation

Small nodes that are visualised on PET are conversely much more likely to be metastatic as such nodes are subject to partial volume effects.

The exception to this rule is tumours with a propensity for tumour heterogeneity at different sites

The combination of FDG and a more specific tracer, which visualises the well-differentiated disease can be very useful to characterise this phenomenon

“metabolic signature”

For the majority of malignant processes, the intensity of metabolic abnormality correlates with degree of aggressiveness or proliferative rate.

a negative PET/CT study in a patient with biopsy proven malignancy would be considered false-negative

Warburg effect

There, however, are a significant minority of tumours that utilise substrates other glucose such as glutamine or fatty acids as a source of the carbon atoms required for growth and proliferation

This includes a subset of diffuse gastric adenocarcinomas, signet cell colonic adenocarcinomas and some sarcomas, particularly liposarcoma

There may be a role for other radiotracers such as fluorothymidine (FLT) or amino acid substrates in this setting.

Some tumours harbour mutations that result in defective aerobic mitochondrial energy metabolism, effectively simulating the Warburg effect

patients with hereditary paraganglioma and pheochromocytoma highlight this phenomenon

These have intense uptake on FDG PET/CT despite often having low proliferative rate.

Uterine fibroids, hepatic adenomas, fibroadenomas of the breast and desmoid tumours are benign or relatively benign lesions that can have quite high FDG-avidity.

Metabolic activity switches off rapidly following initiation of therapy

Common examples where patients have commenced active therapy but the referrer is requesting “staging” includes hormonal therapy (eg. tamoxifen) in breast cancer, oral capecitabine in colorectal cancer or high dose steroids in Hodgkin’s lymphoma

It is therefore critical to perform PET staging before commencement of anti-tumour therapy

The potential advantage of routine diagnostic CT is improved anatomic localisation and definition

Without intravenous contrast, additional identification of typical oncologic complications such as pulmonary embolism or venous thrombosis cannot be identified

If the study is performed as an “interim” restaging study after commencement of therapy but before completion, in order to reach a valid or clinically useful conclusion findings must be interpreted in the context of known changes that occur at a specific timing and type of therapy

The most well studied use of interim PET is in Hodgkin’s lymphoma where repeat PET after two cycles of ABVD-chemotherapy provides powerful prognostic information and may improve outcomes by enabling early change of management

basal (diurnal) concentrations of cortisol do not exert an anti-inflammatory effect on several pro-and anti-inflammatory mediators of the human immune inflammatory response

withdrawal of cortisol activity in vivo did not lead to increased inflammatory responsiveness of immune effector cells

maximal suppression of inflammation was achieved by a stress-associated, but still physiologic, cortisol concentration. There was no greater anti-inflammatory effect at higher cortisol concentrations (Yeager et al. 2005) although IL-10 concentrations continued to increase with increasing cortisol concentrations as we and others have shown

acutely, physiological cortisol concentrations are anti-inflammatory and, as proposed, act to limit over expression of an inflammatory response that could lead to tissue damage

Acutely, cortisol has anti-inflammatory effects following a systemic inflammatory stimulus (Figure 4). However, a cortisol concentration that acts acutely to suppress systemic inflammation also has a delayed effect of augmenting the inflammatory response to subsequent, delayed stimulu

1) GCs can exert pro-inflammatory effects on key inflammatory processes and, 2) GC regulation of inflammation can vary from anti- to a pro-inflammatory in a time-dependent manner

The immediate in vivo effect of both stress-induced and pharmacological GC concentrations is to suppress concurrent inflammation and protect the organism from an excessive or prolonged inflammatory response

GCs alone, in the absence of an inflammatory stimulus, up-regulate monocyte mRNA and/or receptors for several molecules that participate in pro-inflammatory signaling, as noted above and in the studies presented here.

In humans, as shown here, if in vivo GC concentrations are elevated concurrent with an inflammatory stimulus, anti-inflammatory effects are observed

In sharp contrast, with a time delay of 12 or more hours between an increased GC concentration and the onset of an inflammatory stimulus, enhancing effects on inflammation are observed. These effects have been shown to persist in humans for up to 6 days

GC-induced enhancement of inflammatory responses is maximal at an intermediate concentration, in our studies at a concentration that approximates that observed in vivo following a major systemic inflammatory stimulus

In addition to enhanced responses to LPS, recently identified pro-inflammatory effects of GCs also show enhanced localization of effector cells at inflammatory sites

we hypothesize that pre-exposure to stress-associated cortisol concentrations “prime” effector cells of the monocyte/macrophage lineage for an augmented pro-inflammatory response by; a) inducing preparative changes in key regulators of LPS signal transduction, and b) enhancing localization of inflammatory effector cells at potential sites of injury

Under steady-state conditions, intracellular GSH is maintained at millimolar concentrations, which keeps cells in a reduced environment and serves as the principal intracellular redox buffer when cells are subjected to an oxidative stressor including H2O2 (26). Glutathione peroxidase (GPx) activity catalyzes the reduction of H2O2 to water with the conversion of GSH to glutathione disulfide (GSSG). Under steady-state conditions, GSSG is recycled back to GSH by glutathione disulfide reductase using reducing equivalents from NADPH. However, under conditions of increased H2O2 flux, this recycling mechanism may become overwhelmed leading to a depletion of intracellular GSH (27, 28).

ascorbate radiosensitization can create an overwhelming oxidative stress to pancreatic cancer cells resulting in oxidation/depletion of the GSH intracellular redox buffer, resulting in cell death.

Treatment with the combination of ascorbate + IR significantly delayed tumor growth compared to controls or ascorbate alone

Ascorbate + IR also significantly increased overall survival compared to controls, IR alone or ascorbate alone

54% of mice treated with the combination of IR + ascorbate had no measurable tumors

Glutathione is a measurable marker indicative of the oxidation state of the thiol redox buffer in cells. In severe systemic oxidative stress, the GSSG/2GSH couple may become oxidized, i.e. the concentration of GSH decreases and GSSG may increase because the capacity to recycle GSSG to GSH becomes rate-limiting

This suggests that the very high levels of pharmacological ascorbate in these experiments may have a pro-oxidant toward red blood cells as seen by a decrease in the capacity of the intracellular redox buffer

These data support the hypothesis that ascorbate radiosensitization does not cause an increase in oxidative damage from lipid-derived aldehydes to other organs.

Our current study demonstrates the potential for pharmacological ascorbate as a radiosensitizer in the treatment of pancreatic cancer.

pharmacological ascorbate enhances IR-induced cell killing and DNA fragmentation leading to induction of apoptosis in HL60 leukemia cells

pharmacological ascorbate significantly decreases clonogenic survival and inhibits the growth of all pancreatic cancer cell lines as a single agent, as well as sensitizes cancer cells to IR

Hurst et al. demonstrated that pharmacological ascorbate combined with IR leads to increased numbers of double-strand DNA breaks and cell cycle arrest when compared to either treatment alone

pharmacological ascorbate could serve as a “pro-drug” for the delivery of H2O2 to tumors

the double-strand breaks induced by H2O2 were more slowly repaired

The combination of ascorbate and IR provide two distinct mechanisms of action: ascorbate-induced toxicity due to extracellular production of H2O2 that then diffuses into cells and causes damage to DNA, protein, and lipids; and radiation-induced toxicity as a result of ROS-induced damage to DNA. In addition, redox metal metals like Fe2+ may play an important role in ascorbate-induced cytotoxicity. By catalyzing the oxidation of ascorbate, labile iron can enhance the rate of formation of H2O2; labile iron can also react with H2O2. Recently our group has demonstrated that pharmacological ascorbate and IR increase the labile iron in tumor homogenates from this murine model of pancreatic cancer

we demonstrated that ascorbate or IR alone decreased tumor growth, but the combination treatment further inhibited tumor growth, indicating that pharmacological ascorbate is an effective radiosensitizer in vivo

data suggest that pharmacological ascorbate may protect the gut locally by decreasing IR-induced damage to the crypt cells, and systemically, by ameliorating increases in TNF-α

Our data show that ascorbic acid selectively killed cancer but not normal cells, using concentrations that could only be achieved by i.v. administration

Ascorbate-mediated cell death was due to protein-dependent extracellular H2O2 generation, via ascorbate radical formation from ascorbate as the electron donor. Like glucose, when ascorbate is infused i.v., the resulting pharmacologic concentrations should distribute rapidly in the extracellular water space (42). We showed that such pharmacologic ascorbate concentrations in media, as a surrogate for extracellular fluid, generated ascorbate radical and H2O2. In contrast, the same pharmacologic ascorbate concentrations in whole blood generated little detectable ascorbate radical and no detectable H2O2. These findings can be accounted for by efficient and redundant H2O2 catabolic pathways in whole blood (e.g., catalase and glutathione peroxidase) relative to those in media or extracellular fluid

ascorbic acid administered i.v. in pharmacologic concentrations may serve as a pro-drug for H2O2 delivery to the extracellular milieu

H2O2 generated in blood is normally removed by catalase and glutathione peroxidase within red blood cells, with internal glutathione providing reducing equivalents

The electron source for glutathione is NADPH from the pentose shunt, via glucose-6-phosphate dehydrogenase. If activity of this enzyme is diminished, the predicted outcome is impaired H2O2 removal causing intravascular hemolysis, the observed clinical finding.

Only recently has it been understood that the discordant clinical findings can be explained by previously unrecognized fundamental pharmacokinetics properties of ascorbate

Intracellular transport of ascorbate is tightly controlled in relation to extracellular concentration

Intravenous ascorbate infusion is expected to drastically change extracellular but not intracellular concentrations

For i.v. ascorbate to be clinically useful in killing cancer cells, pharmacologic but not physiologic extracellular concentrations should be effective, independent of intracellular ascorbate concentrations.

It is unknown why ascorbate, via H2O2, killed some cancer cells but not normal cells.

There was no correlation with ascorbate-induced cell death and glutathione, catalase activity, or glutathione peroxidase activity.

H2O2, as the product of pharmacologic ascorbate concentrations, has potential therapeutic uses in addition to cancer treatment, especially in infections

Neutrophils generate H2O2 from superoxide,

i.v. ascorbate is effective in some viral infections

H2O2 is toxic to hepatitis C

Use of ascorbate as an H2O2-delivery system against sensitive pathogens, viral or bacterial, has substantial clinical implications that deserve rapid exploration.

Recent pharmacokinetics studies in men and women show that 10 g of ascorbate given i.v. is expected to produce plasma concentrations of nearly 6 mM, which are >25-fold higher than those concentrations from the same oral dose

As much as a 70-fold difference in plasma concentrations is expected between oral and i.v. administration,

Complementary and alternative medicine practitioners worldwide currently use ascorbate i.v. in some patients, in part because there is no apparent harm

Human Burkitt's lymphoma cells

We first investigated whether ascorbate in pharmacologic concentrations selectively affected the survival of cancer cells by studying nine cancer cell lines

Clinical pharmacokinetics analyses show that pharmacologic concentrations of plasma ascorbate, from 0.3 to 15 mM, are achievable only from i.v. administration

plasma ascorbate concentrations from maximum possible oral doses cannot exceed 0.22 mM because of limited intestinal absorption

For five of the nine cancer cell lines, ascorbate concentrations causing a 50% decrease in cell survival (EC50 values) were less than 5 mM, a concentration easily achievable from i.v. infusion

All tested normal cells were insensitive to 20 mM ascorbate.

Lymphoma cells were selected because of their sensitivity to ascorbate

As ascorbate concentration increased, the pattern of death changed from apoptosis to pyknosis/necrosis, a pattern suggestive of H2O2-mediated cell death

Apoptosis occurred by 6 h after exposure, and cell death by pyknosis was ≈90% at 14 h after exposure

In contrast to lymphoma cells, there was little or no killing of normal lymphocytes and monocytes by ascorbate

Ascorbate is transported into cells as such by sodium-dependent transporters, whereas dehydroascorbic acid is transported into cells by glucose transporters and then immediately reduced internally to ascorbate

Whether or not intracellular ascorbate was preloaded, extracellular ascorbate induced the same amount and type of death.

extracellular ascorbate in pharmacologic concentrations mediates death of lymphoma cells by apoptosis and pyknosis/necrosis, independently of intracellular ascorbate.

H2O2 as the effector species mediating pharmacologic ascorbate-induced cell death

Superoxide dismutase was not protective

Because these data implicated H2O2 in cell killing, we added H2O2 to lymphoma cells and studied death patterns using nuclear staining (19, 28). The death patterns found with exogenous H2O2 exposure were similar to those found with ascorbate

For both ascorbate and H2O2, death changed from apoptosis to pyknosis/necrosis as concentrations increased

Sensitivity to direct exposure to H2O2 was greater in lymphoma cells compared with normal lymphocytes and normal monocytes

There was no association between the EC50 for ascorbate-mediated cell death and intracellular glutathione concentrations, catalase activity, or glutathione peroxidase activity

H2O2 generation was dependent on time, ascorbate concentration, and the presence of trace amounts of serum in media

ascorbate radical is a surrogate marker for H2O2 formation.

whatever H2O2 is generated should be removed by glutathione peroxidase and catalase within red blood cells, because H2O2 is membrane permeable

The data are consistent with the hypothesis that ascorbate in pharmacologic concentrations is a pro-drug for H2O2 generation in the extracellular milieu but not in blood.

The occurrence of one predicted complication, oxalate kidney stones, is controversial

In patients with glucose-6-phosphate dehydrogenase deficiency, i.v. ascorbate is contraindicated because it causes intravascular hemolysis

ascorbate at pharmacologic concentrations in blood is a pro-drug for H2O2 delivery to tissues.

ascorbate, an electron-donor in such reactions, ironically initiates pro-oxidant chemistry and H2O2 formation

data here showed that ascorbate initiated H2O2 formation extracellularly, but H2O2 targets could be either intracellular or extracellular, because H2O2 is membrane permeant

More than 100 patients have been described, presumably without glucose-6-phosphate dehydrogenase deficiency, who received 10 g or more of i.v. ascorbate with no reported adverse effects other than tumor lysis

LDN may be an effective treatment for FM

In addition to the antagonist effect on mu-opioid and other opioid receptors, naltrexone simultaneously has an antagonist effect on non-opioid receptors (Toll-like receptor 4 or TLR4) that are found on macrophages such as microglia

It is via the non-opioid antagonist path that LDN is thought to exert its anti-inflammatory effects

Once activated, microglia produce inflammatory and excitatory factors that can cause sickness behaviors such as pain sensitivity, fatigue, cognitive disruption, sleep disorders, mood disorders, and general malaise

The neuroprotective action appears to result when microglia activation in the brain and spinal cord is inhibited

By suppressing microglia activation, naloxone reduces the production of reactive oxygen species and other potentially neuroexcitatory and neurotoxic chemicals

suppressed TNF-alpha, IL-6, MCP-1, and other inflammatory agents in peripheral macrophages

individuals with greater ESR at baseline experienced a greater drop in pain when taking LDN

LDN has been reported to reduce not only self-reported pain in that condition but also objective markers of inflammation and disease severity

Naltrexone has also shown some promise in improving disease severity in multiple sclerosis

Ivermectin inhibits proliferation of human colon cancer and lung cancer cells both in vitro and in vivo

The anti-proliferative action, affecting both the bulk tumor cells and CSCs, was linked in this study to inhibition of WNT signaling

the anti-WNT IC50 of ivermectin is 5–10 times (~1–2 µM vs. 10 µM) lower than that of its toxic effect against chloride channels

oral bioavailability of the drug, as for other antiparasitic drugs discussed in this section, is very low

Toxicity studies in vivo have also demonstrated a wide therapeutic index for ivermectin

Its anti-proliferative activity has been demonstrated in a wide array of cancer cell lines representative of WNT-dependent cancers: non-small lung carcinoma [96], multiple myeloma [97], hepatoma [98], adrenocortical carcinoma [99], ovarian cancer [100] and glioblastoma

Niclosamide inhibits the canonical WNT pathway

In addition to inhibiting the canonical WNT pathway, niclosamide may mediate its anticancer activities through several other signaling pathways such as NOTCH [107], MTOR [108], NF-κB [97] and STAT3 [96]

increasing evidence that treatment with chemotherapy or chemoradiotherapy can induce EMT in NSCLC which in turn is thought to generate CSCs which are generally resistant to such treatments

cisplatin has been shown to increase the release of Interleukin‐6 (IL‐6) and expression of transforming growth factor beta (TGF‐β)

EMT confers an invasive phenotype and

IL‐6 serves to block apoptosis in cells

colocalization of the Bb 23S rRNA probe was not observed in any of the sections of experimental inoculated animals shown to harbor rare persistent spirochetes (Supplemental Figure S1). Previous in vitro work has shown large decreases in Bb rRNA levels when in a stationary phase of growth despite the majority of spirochetes remaining viable

The possibility that the spirochetes were intact but dead also exists, though this may be unlikely given the precedence for viable but non-cultivable B. burgdorferi post-treatment

The doxycycline dose utilized in this study (5mg/kg) was based on a previous pharmacokinetic analysis of oral doxycycline in rhesus macaques proven to be comparable to levels achieved in humans and was meant to mimic treatment of disseminated LD

In addition to the brain of two treated animals, rare morphologically intact spirochetes immunoreactive to OspA were observed in the heart of one treated animal

Although we did not measure the doxycycline levels in the cerebrospinal fluid, they have been found to be 12% to 15% of the amount measured in serum

We and others have demonstrated the development of a drug-tolerant persister population when B. burgdorferi are treated with antibiotics in vitro

The adoption of a dormant or slow-growing phenotype likely allows the spirochetes to survive and re-grow following removal of antibiotic

The basic premise that antibiotic tolerance may be an adaptation of the sophisticated stringent response required for the enzootic cycle by the spirochetes is described in a recent review as well

Although current IDSA guidelines recommend intravenous ceftriaxone (2g daily for 30 days) over oral doxycycline for treatment of neuroborreliosis, a randomized clinical trial failed to show any enhanced efficacy of I.V. penicillin G to oral doxycycline for treatment of Lyme neuroborreliosis (no treatment failures were reported in this study of 54 patients).

we can speculate that the minimal to moderate inflammation that was observed, especially within the CNS and PNS can, in part, explain the breadth of symptoms experienced by late stage Lyme disease patients, such as cognitive impairment and neuralgia.

Erythema migrans, the clinical hallmark of early localized Lyme disease, was observed in one of the rhesus macaques from this study.

In 2014, a trailblazing study in mice demonstrated a dramatic decline in B. burgdorferi DNA in the tissues for up to eight months after antibiotic treatment followed by the resurgence of B. burgdorferi growth 12 months after treatment

This study provides evidence that the slow-growing spirochetes which persist after treatment, but are not cultivable in standard growth media may remain viable.

The first well-documented indication of Lyme disease (LD) in the United States occurred in the early 1970s

Lyme, Connecticut.

Lyme disease is now known to be caused by multiple closely related genospecies classified within the Bb sensu lato complex, representing the most common tick-borne human disease in the Northern Hemisphere

approximately 30,000 physician-reported cases occur annually in the United States, the annual incidence has been estimated to be 10-fold higher by the Centers for Disease Control and Prevention.6

Current antibiotic therapy guidelines outlined by the Infectious Disease Society of America (IDSA) are successful in the treatment of LD for the majority of LD patients, especially when administered early in disease immediately following identification of erythema migrans (EM)

‘post-treatment Lyme disease syndrome’ (PTLDS)

host-adapted spirochetes that persist in the tissues, probably in small numbers, inaccessible or impervious to antibiotic

inflammatory responses to residual antigens from dead organisms

residual tissue damage following pathogen clearance;

autoimmune responses, possibly elicited by antigenic mimicry

Experimental studies on immunocompetent mice, dogs, and rhesus macaques have provided evidence for the persistence of Bb spirochetes subsequent to antibiotic treatment in the form of residual spirochetes detected within tissue by IFA and PCR, and recovered by xenodiagnoses

Ten male rhesus macaques

half (five) of the NHP received antibiotic treatment, consisting of 5 mg/kg oral doxycycline twice per day.

Minimal and focal lymphoplasmacytic inflammation

inflammation was observed in the leptomeninges overlying a section of temporal cerebral cortex

Minimal localized lymphoplasmacytic choroiditis

Peripheral nerves contained minimal to moderate lymphoplasmacytic inflammation with a predilection for collagen-rich epineurium and perivascular spaces

Inflammation was observed in 56% (5/9) of the NHPs irrespective of treatment group

For all animals, inflammation was reserved to perineural tissue

The treatment lasted 28 days

Minimal to mild lymphoplasmacytic inflammation of either the myocardial interstitium (Figure 2Figure 2A), pericardium (Figure 2Figure 2B), or combination therein was observed in 60% of NHPs

A single morphologically intact spirochete, as indicated by positive red immunofluorescence (Figure 2Figure 2C), was observed in the myocardium of one treated animal

mild, multifocal lymphoplasmacytic inflammation was observed in one doxycycline-treated animal

three animals exhibited minimal to mild lymphoplasmacytic inflammation affecting joint-associated structures

10% to -20% of human patients treated

Multiple randomized placebo-controlled studies which evaluated sustained antimicrobial therapy concluded that there is no benefit in alleviating patients’ symptoms and indicated that long-term antibiotic therapy may even be detrimental to patients due to potential associated complications (ie, catheter infection and/or clostridial colitis)

and the rapid clearance of dead spirochetes in a murine model

higher doses may be needed to combat neuroborreliosis

Results of this study demonstrated not only persistence, but also resurgence of non-cultivable B. burgdorferi in tissues of mice at up to 12 months following antibiotic treatment

“Intrinsic processes” include those that result in mutations due to random errors in DNA replication whereas “extrinsic factors” are environmental factors that affect mutagenesis rates (such as UV radiation, ionizing radiation, and carcinogens

intrinsic factors do not play a major causal role.

intrinsic cancer risk should be determined by the cancer incidence for those cancers with the least risk in the entire group controlling for total stem cell divisions

if one or more cancers would feature a much higher cancer incidence, for example, lung cancer among smokers vs. non-smokers, then this most likely reflects additional (and probably extrinsic) risk factors (smoking in this case)

Particularly, for breast and prostate cancers, it has long been observed that large international geographical variations exist in their incidences (5-fold for breast cancer, 25-fold for prostate cancer)14, and immigrants moving from countries with lower cancer incidence to countries with higher cancer rates soon acquire the higher risk of their new country

Colorectal cancer is another high-incidence cancer that is widely considered to be an environmental disease17, with an estimated 75% or more colorectal cancer risk attributable to diet

melanoma, its risk ascribed to sun exposure is around 65–86%

non-melanoma basal and squamous skin cancers, ~90% is attributable to UV

75% of esophageal cancer, or head and neck cancer are caused by tobacco and alcohol

HPV may cause ~90% cases in cervical cancer23, ~90% cases in anal cancer24, and ~70% in oropharyngeal cancer

HBV and HCV may account for ~80% cases of hepatocellular carcinoma

H pylori may be responsible for 65–80% of gastric cancer

While a few cancers have relatively large proportions of intrinsic mutations (>50%), the majority of cancers have large proportions of extrinsic mutations, for example, ~100% for Myeloma, Lung and Thyroid cancers and ~80–90% for Bladder, Colorectal and Uterine cancers, indicating substantial contributions of carcinogen exposures in the development of most cancers

onsistent estimate of contribution of extrinsic factors of >70–90% in most common cancer types. This concordance lends significant credibility to the overall conclusion on the role of extrinsic factors in cancer development

surgery per se can promote cancer metastasis through a series of local and systemic events

surgery results in a serious wound that disrupts the structural barrier preventing the outspreading of cancer cells, change the properties of the cancer cells and stromal cells remaining in the tumor microenvironment, or impairs the host defense systems against cancers

After the primary tumor is surgically removed, the metastases can start to grow vigorously via neoangiogenesis because the circulating inhibitors disappear

infection and inflammation during the postoperative period have been reported to increase the risk of cancer recurrence in patients

Surgeons have long suspected that surgery, even if it is a necessary step in cancer treatment, facilitates cancer metastasis

Surgery-induced cancer metastasis has been well established in animal models

tumor cell dissemination, tumor-favoring immune responses, and neoangiogenesis

the surgical resection of primary tumors is beneficial is controversial

CTCs abruptly increase just after surgery

Even externally palpitating tumors for diagnosis could increase the numbers of CTCs in skin cancer and breast cancer

excessive glucocorticoids negatively modulate immune functions

immune surveillance against tumors is considered to be impaired by surgical stress

In addition to glucocorticoids, during stimulation of the HPA axis, the catecholamine hormones epinephrine and norepinephrine are released from the adrenal medulla

NK cell suppression may be attributed to increased levels of catecholamines as well as glucocorticoids

In mice bearing a primary tumor, it was observed that the removal of the primary tumor facilitated the growth of highly vascularized metastases

primary tumors may secrete angiogenic inhibitors as well as angiogenic activators

second phase of tumor recurrence and metastasis, which are newly acquired events, rather than just outcomes of incomplete treatment.

double-edged sword

HIF-1 in neutrophils plays a critical role in NETosis and bacteria-killing activity

neutrophils play various roles in the initiation and progression of cancer

NETosis

many inflammatory and neoplastic diseases

formation of neutrophil extracellular traps (NETs), which are large extracellular complexes composed of chromatin and cytoplasmic/granular proteins1

NETosis has been highlighted as an inflammatory event that promotes cancer metastasis

Once activated, neutrophils produce intracellular precursors by using DNA, histones, and granular and cytoplasmic proteins and then spread the mature form of NETs out around themselves

A series of these events is called NETosis.

neutrophil elastase, myeloperoxidase, cathepsin G, proteinase 3, lactoferrin, gelatinase, lysozyme C, calprotectin, neutrophil defensins, and cathelicidins

innate immune response against infection

Neutrophils are the most abundant type of granulocytes, comprising 40–70% of all white blood cells

two types of NEToses, suicidal (or lytic) NETosis and vital NETosis

Suicidal NETosis mainly depends on the production of reactive oxygen species (ROS)

Since neutrophils die during this process, it is called suicidal NETosis.

vital NETosis

vital NETosis occurs independently of ROS production

Vital NETosis can be induced by Gram-negative bacteria. LPS

NETs are present in a variety of cancers, such as lung cancer, colon cancer, ovarian cancer, and leukemia

neutrophils actively undergo NETosis in the tumor microenvironment

Hypoxia

NETosis plays a pivotal role in noninfectious autoimmune diseases,

cytokines

tumor-derived proteases

tumor exosomes

NETosis generally actively progresses in the tumor microenvironment.

the proliferative cytokines TGFβ and IL-10 and the angiogenic factor VEGF are representative of neutrophil-derived tissue repair proteins.

NETosis is a defense system to protect the body from invading pathogens

when neutrophils are excessively stimulated, they produce excess NETs, thereby leading to pathological consequences

plasma levels of NETosis markers are elevated after major surgeries

local invasion, intravasation into the blood or lymphatic vessels, escape from the immune system, anchoring to capillaries in target organs, extravasation into the organs, transformation from dormant cells to proliferating cells, colonization to micrometastases, and growth to macrometastases

NETs promote metastasis at multiple steps

NETs loosen the ECM and capillary wall to promote the intravasation of cancer cells

NETs and platelets wrap CTCs, which protects them from attack by immune cells and shearing force by blood flow

NETs promote the local invasion of cancer cells by degrading the extracellular matrix (ECM)

neutrophil elastase, matrix metalloproteinase 9, and cathepsin G

NETs also promote the intravasation of cancer cells

millions of tumor cells are released into the circulation every day,

NETs can wrap up CTCs with platelets

β1-integrin plays an important role in the interaction between CTCs and NETs

NET-platelet-CTC aggregates.

After metastasizing to distant tissues, tumor cells are often found to remain dormant for a period of time and unexpectedly regrow late

NETs are believed to participate in the reactivation of dormant cancer cells in metastatic regions

NET-associated proteases NE and MMP-9 were found to be responsible for the reactivation of dormant cancer cells

bone marrow suppression

cardiomyopathy

irreversible retinal toxicity

hypoglycaemia

daily doses up to 400 mg of HCQ or 250 mg CQ for several years are considered to carry an acceptable risk for CQ-induced retinopathies, with the exception of individuals of short stature

chronic CQ or HCQ therapy be monitored through regular ophthalmic examinations (3–6 month intervals), full blood counts and blood glucose level checks

long-term HCQ exposure, skeletal muscle function and tendon reflexes should be monitored for weakness

both CQ and HCQ, specific caution is advised in patients suffering from impaired hepatic function (especially when associated with cirrhosis), porphyria, renal disease, epilepsy, psoriasis, glucose-6-phosphate dehydrogenase deficiency and known hypersensitivity to 4-aminoquinoline compounds

CQ and HCQ can effectively increase the efficacy of various anti-cancer drugs

CQ can prevent the entrapment of protonated chemotherapeutic drugs by buffering the extracellular tumour environment and intracellular acidic spaces

This study recommends an adjuvant HCQ dose of 600 mg, twice daily.

HCQ addition was shown to produce metabolic stress in the tumours

HCQ (400 mg/day)

important effects of CQ and HCQ on the tumour microenvironment

The main and most studied anti-cancer effect of CQ and HCQ is the inhibition of autophagy

the expression levels of TLR9 are higher in hepatocellular carcinoma, oesophageal, lung, breast, gastric and prostate cancer cells as compared with adjacent noncancerous cells, and high expression is often linked with poor prognosis

TLR9-mediated activation of the NF-κB signalling pathway and the associated enhanced expression of matrix metalloproteinase-2 (MMP-2), MMP-7 and cyclo-oxygenase 2 mRNA

HCQ can activate caspase-3 and modulate the Bcl-2/Bax ratio inducing apoptosis in CLL, B-cell CLL and glioblastoma cells

In triple-negative breast cancer, CQ was shown to eliminate cancer stem cells through reduction of the expression of Janus-activated kinase 2 and DNA methyl transferase 1 [106] or through induction of mitochondrial dysfunction, subsequently causing oxidative DNA damage and impaired repair of double-stranded DNA breaks

CQ or HCQ would be considered for use in combination with immunomodulation anti-cancer therapies

Therapies used in combination with CQ or HCQ include chemotherapeutic drugs, tyrosine kinase inhibitors, various monoclonal antibodies, hormone therapies and radiotherapy

Most studies hypothesise that CQ and HCQ could increase the efficacy of other anti-cancer drugs by blocking pro-survival autophagy.

daily doses between 400 and 1200 mg for HCQ are safe and well tolerated, but two studies identified 600-mg HCQ daily as the MTD

HCQ is often administered twice daily to limit plasma fluctuations and toxicity

pharmacologic ascorbate as a prooxidant drug for therapeutic use.

Recently we reported that pharmacologic ascorbic acid concentrations produced H2O2 concentrations of ≥25 μM, causing cancer cell death in vitro

We found that H2O2 concentrations generated in vivo were those that caused cancer cell death in vitro

When ascorbate was given parenterally, Asc•−, the product of a loss of one electron from ascorbate, was detected preferentially in extracellular fluid compared with blood

Asc•− generation in extracellular fluid depended on the ascorbate dose and the resulting concentrations

With i.v. administration of ascorbate, Asc•− concentrations were as much as 12-fold greater in extracellular fluid compared to blood and approached 250 nM

In blood, such Asc•− concentrations were never produced and were always <50 nM

These data are all consistent with the hypothesis that pharmacologic ascorbate concentrations in vivo serve as a prodrug for selective delivery of H2O2 to the extracellular space

After oral ingestion, control of intracellular and extracellular ascorbate concentrations is mediated by three mechanisms: intestinal absorption, tissue transport, and renal reabsorption

intestinal absorption, or bioavailability, declines at doses >200 mg

corresponding to plasma concentrations of ≈60 μM

at approximately this concentration, the ascorbate tissue transporter SVCT2 approaches Vmax, and tissues appear to be saturated

also at ≈60 μM, renal reabsorption approaches saturation, and excess ascorbate is excreted in urine

Parenteral administration bypasses tight control

When tight control is bypassed, H2O2 forms in the extracellular space

in vivo validation of ascorbate as a prodrug for selective H2O2 formation

Temporarily bypassing tight control with parenteral administration of ascorbate allows H2O2 to form in discrete time periods only, decreasing likelihood of harm, and provides a pharmacologic basis for therapeutic use of i.v. ascorbate

H2O2 formation results in selective cytotoxicity

Tumor cells are killed with exposure to H2O2 for ≤30 min

In vitro, killing is mediated by H2O2 rather than Asc•−

In addition to cancer treatment, another potential therapeutic use is for treatment of infections. H2O2 concentrations of 25–50 μM are bacteriostatic

virally infected cells may also be candidates