Colorectal cancer and pollution

Pollutants, microbiota and immune system: frenemies within the gut

Pollution is a critical concern of modern society for its heterogeneous effects on human health, despite a widespread lack of awareness. Environmental pollutants promote several pathologies through different molecular mechanisms. Pollutants can affect the immune system and related pathways, perturbing its regulation and triggering pro-inflammatory responses. The exposure to several pollutants also leads to alterations in gut microbiota with a decreasing abundance of beneficial microbes, such as short-chain fatty acid-producing bacteria, and an overgrowth of pro-inflammatory species. The subsequent intestinal barrier dysfunction, together with oxidative stress and increased inflammatory responses, plays a role in the pathogenesis of gastrointestinal inflammatory diseases. Moreover, pollutants encourage the inflammation-dysplasia-carcinoma sequence through various mechanisms, such as oxidative stress, dysregulation of cellular signalling pathways, cell cycle impairment and genomic instability. In this narrative review, we will describe the interplay between pollutants, gut microbiota, and the immune system, focusing on their relationship with inflammatory bowel diseases and colorectal cancer. Understanding the biological mechanisms underlying the health-to-disease transition may allow the design of public health policies aimed at reducing the burden of disease related to pollutants.

Cholesterol in colorectal cancer: an essential but tumorigenic precursor?

Colorectal cancer (CRC) is one of the most lethal human malignancies, and with the growth of societies and lifestyle changes, the rate of people suffering from it increases yearly. Important factors such as genetics, family history, nutrition, lifestyle, smoking, and alcohol can play a significant role in increasing susceptibility to this cancer. On the other hand, the metabolism of several macromolecules is also involved in the fate of tumors and immune cells. The evidence discloses that cholesterol and its metabolism can play a role in the pathogenesis of several cancers because there appears to be an association between cholesterol levels and CRC, and cholesterol-lowering drugs may reduce the risk. Furthermore, changes or mutations of some involved genes in cholesterol metabolism, such as CYP7A1 as well as signaling pathways, such as mitogen-activated protein kinase (MAPK), can play a role in CRC pathogenesis. This review summarized and discussed the role of cholesterol in the pathogenesis of CRC as well as available cholesterol-related therapeutic approaches in CRC.

Exposome approach for identifying modifiable factors for the prevention of colorectal cancer

Previous studies have shown certain exposure factors (such as lifestyle and metabolism) are associated with colorectal cancer (CRC) events. However, the application of the exposome theoretical frame and the extent to which the exposome domain can modulate the risk of CRC remain unknown. Our study aimed to construct valid exposome measurements and examine the relationship between exposome counts and the risk of CRC. This study included 335,370 individuals in the UK Biobank. We used exploratory factor analysis to identify a valid construct of exposome factors. We then summed the exposome counts within each domain. Cox proportional hazard models were used to estimate the hazard ratios and 95% confidence intervals of CRC risk related to the exposome factors and counts. During an 8.69 year median follow-up, 10,702 CRC cases were identified. Five domains were extracted from 12 variables, including ecosystem, lifestyle, tobacco and alcohol use, social economics, and social support. The Cox model results showed that the ecosystem was positively related to the reduced CRC risk (HR = 0.970; 95% CI 0.952-0.989). Similar results were also found among the domains of healthy lifestyles (HR = 0. 889; 95% CI 0.871-0.907), and no tobacco and alcohol use (HR = 0.892; 95% CI 0.876-0.909). The disadvantageous social economic (HR = 1.081; 95% CI 1.058-1.105) and insufficient social support domains (HR = 1.036; 95% CI 1.017-1.056) were associated with an increased risk of CRC. Similar risk trends were also observed across the exposome count groups with CRC incidence. Our findings suggest that certain exposure domains are related to the incidence of CRC. Ecosystem, lifestyle, and social factors can be incorporated into prediction models to identify individuals at high risk of CRC.

Early-Onset Colorectal Cancer Survival Differences and Potential Geographic Determinants Among Men and Women in Utah

By 2030, early-onset colorectal cancer (EOCRC) is expected to become the leading cancer-related cause of death for people age 20 to 49. To improve understanding of this phenomenon, we analyzed the geographic determinants of EOCRC in Utah by examining county-level incidence and mortality. We linked data from the Utah Population Database to the Utah Cancer Registry to identify residents (age 18-49) diagnosed with EOCRC between 2000 and 2020, and we used spatial empirical Bayes smoothing to determine county-level hotspots. We identified 1,867 EOCRC diagnoses (52.7% in male patients, 69.2% in non-Hispanic White patients). Ten counties (34%) were classified as hotspots, with high EOCRC incidence or mortality. Hotspot status was unrelated to incidence rates, but non-Hispanic ethnic-minority men (incidence rate ratio, 1.49; 95% CI, 1.15-1.91), Hispanic White men and women (incidence rate ratio, 2.24; 95% CI, 2.00-2.51), and Hispanic ethnic-minority men and women (incidence rate ratio, 4.59; 95% CI, 3.50-5.91) were more likely to be diagnosed with EOCRC. After adjustment for income and obesity, adults living in hotspots had a 31% higher hazard for death (HR, 1.31; 95% CI, 1.02-1.69). Survival was poorest for adults with a late-stage diagnosis living in hotspots (chi square (1) = 4.0; p = .045). Adults who were married or who had a life partner had a lower hazard for death than single adults (HR, 0.73; 95% CI, 0.58-0.92). The risk for EOCRC is elevated in 34% of Utah counties, warranting future research and interventions aimed at increasing screening and survival in the population age 18 to 49.

Colorectal Cancer in Lebanon: Incidence, Temporal Trends, and Comparison to Regional and Western Countries

Global trends in the incidence and mortality rates of colorectal cancer show a steady increase with significant predilection to western developed countries, possibly linking it to westernized lifestyles among other risk factors. This study aims to investigate the incidence and trends of colorectal cancer in Lebanon, a country in the Middle East and North Africa region, and to compare these rates to those in regional and western countries. Colorectal cancer incidence data were extracted from the Lebanese National Cancer Registry for the currently available years 2005 to 2016. The calculated age-standardized incidence rates and age-specific rates were expressed as per 100,000 population. The age-standardized incidence rates of colorectal cancer in Lebanon increased from 16.3 and 13.0 per 100,000 in 2005 to 23.2 and 20.2 per 100,000 in 2016, among males and females, respectively. The incidences were higher for males, and they increased with age. The annual percent change was +4.36% and +4.45%, in males and females respectively (p-value < 0.05). There was a non-statistically significant trend of decrease in recent years (since 2012 in males and since 2011 in females). The age-standardized incidence rates in Lebanon were higher than those in the majority of the regional countries, but lower than the rates in developed western countries. There were high age-specific incidence rates at age groups 40-44 and 45-49 years in Lebanon in both males and females (with significant rising temporal trend) compared to other countries, including the ones reported to have the highest colorectal cancer age-standardized incidence rate worldwide. Therefore, the burden of colorectal cancer is significant in Lebanon. This raises the necessity to develop national strategies tailored to reduce colorectal cancer incidence through promoting healthy lifestyles, raising awareness, and early detection as of 40 years of age.

Residential proximity to industrial pollution sources and colorectal cancer risk: A multicase-control study (MCC-Spain)

BACKGROUND

Colorectal cancer is the third most frequent tumor in males and the second in females worldwide. In Spain, it is an important and growing health problem, and epidemiologic research focused on potential risk factors, such as environmental exposures, is necessary.

OBJECTIVES

To analyze the association between colorectal cancer risk and residential proximity to industries, according to pollution discharge route, industrial groups, categories of carcinogens and other toxic substances, and specific pollutants released, in the context of a population-based multicase-control study of incident cancer carried out in Spain (MCC-Spain).

METHODS

MCC-Spain included 557 colorectal cancer cases and 2948 controls in 11 provinces, frequency matched by sex, age, and region of residence. Distances were computed from subjects' residences to each of the 134 industries located in the study area. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95%CIs) for categories of distance (from 1 km to 3 km) to industrial facilities, adjusting for matching variables and other confounders.

RESULTS

Excess risk (OR; 95%CI) of colorectal cancer was detected near industries overall for all distances analyzed, from 1 km (2.03; 1.44-2.87) to 3 km (1.26; 1.00-1.59). In general, industries releasing pollutants to air showed higher excess risks than facilities releasing pollution to water. By industrial sector, excess risk (OR; 95%CI) was found near (≤3 km) production of metals (2.66; 1.77-4.00), surface treatment of metals (1.48; 1.08-2.02), glass and mineral fibers (2.06; 1.39-3.07), organic chemical industry (4.80; 3.20-7.20), inorganic chemical industry (6.74; 4.38-10.36), food/beverage sector (3.34; 2.38-4.68), and surface treatment using organic solvents (6.16; 4.06-9.36). By pollutants, the main excess risks (OR; 95%CI) were found near (≤3 km) industries releasing nonylphenol (9.19; 5.91-14.28), antimony (5.30; 3.45-8.15), naphthalene (3.11; 2.16-4.49), organotin compounds (2.64; 1.76-3.98), manganese (2.53; 1.63-3.93), dichloromethane (2.52; 1.74-3.66), and vanadium (2.49; 1.59-3.91).

CONCLUSIONS

Our results support the hypothesis that residing in the proximity of industries may be a risk factor for colorectal cancer.

XRCC2 Polymorphisms and Environmental Factors Predict High Risk of Colorectal Cancer

Background

This case-control study aimed to analyze the association of XRCC2 polymorphisms (rs3218408 and rs3218384) with colorectal cancer (CRC) risk. The interaction of XRCC2 polymorphisms with environmental factors was investigated as well.

Material/Methods

We enrolled 147 CRC patients and 114 healthy individuals into the study. Polymerase chain reaction (PCR)-sequencing method was performed to detect rs3218408 and rs3218384 polymorphisms. Hardy-Weinberg equilibrium (HWE) was checked in the control group. Odds ratio (OR) with 95% confidence interval (CI) represented the risk of CRC. Cross-table method was used in analyzing the interaction effects.

Results

Compared to the control group, the frequency of smokers was much higher in the case group (P<0.001). A similar result was observed in drinkers (55.8% vs. 40.4%, P=0.013). Dietary habits of all subjects were investigated as well, showing that CRC patients ate fewer vegetables than did healthy controls (P<0.001). In the analysis of polymorphisms, rs3218408 appeared to be an independent risk factor of CRC (GG: OR=2.048, 95%CI=1.032–4.061; G allele: OR=1.445, 95%CI=1.019–2.049). There were 68 (76.4%) C allele carriers (rs3218384) among smokers, which was higher than the number of G allele carriers (P<0.001). A similar outcome was observed for alcohol drinkers (P=0.048), which suggests a relationship of rs3218384 with smoking and drinking. Further analysis indicated that interaction of rs3218384 with smoking increased the risk of CRC (GG and smoking: OR=3.250, 95%CI=1.235–8.556; GC+CC and smoking: OR=2.167, 95%CI=1.175–3.996).

Conclusions

We found that rs3218408 was related with increased risk of CRC, and the interaction of rs3218384 with smoking increased the risk of CRC.

Impacts of soil and water pollution on food safety and health risks in China

Environmental pollution and food safety are two of the most important issues of our time. Soil and water pollution, in particular, have historically impacted on food safety which represents an important threat to human health. Nowhere has that situation been more complex and challenging than in China, where a combination of pollution and an increasing food safety risk have affected a large part of the population. Water scarcity, pesticide over-application, and chemical pollutants are considered to be the most important factors impacting on food safety in China. Inadequate quantity and quality of surface water resources in China have led to the long-term use of waste-water irrigation to fulfill the water requirements for agricultural production. In some regions this has caused serious agricultural land and food pollution, especially for heavy metals. It is important, therefore, that issues threatening food safety such as combined pesticide residues and heavy metal pollution are addressed to reduce risks to human health. The increasing negative effects on food safety from water and soil pollution have put more people at risk of carcinogenic diseases, potentially contributing to 'cancer villages' which appear to correlate strongly with the main food producing areas. Currently in China, food safety policies are not integrated with soil and water pollution management policies. Here, a comprehensive map of both soil and water pollution threats to food safety in China is presented and integrated policies addressing soil and water pollution for achieving food safety are suggested to provide a holistic approach.

p,p′-Dichlorodiphenyltrichloroethane inhibits the apoptosis of colorectal adenocarcinoma DLD1 cells through PI3K/AKT and Hedgehog/Gli1 signaling pathways

p,p′-Dichlorodiphenyltrichloroethane is able to inhibit the apoptosis of human colorectal adenocarcinoma cells, which may be an important mechanism to contribute to colorectal cancer development.

p, p'-Dichlorodiphenyldichloroethylene induces colorectal adenocarcinoma cell proliferation through oxidative stress

p, p'-Dichlorodiphenyldichloroethylene (DDE), the major metabolite of Dichlorodiphenyltrichloroethane (DDT), is an organochlorine pollutant and associated with cancer progression. The present study investigated the possible effects of p,p'-DDE on colorectal cancer and the involved molecular mechanism. The results indicated that exposure to low concentrations of p,p'-DDE from 10(-10) to 10(-7) M for 96 h markedly enhanced proliferations of human colorectal adenocarcinoma cell lines. Moreover, p,p'-DDE exposure could activate Wnt/β-catenin and Hedgehog/Gli1 signaling cascades, and the expression level of c-Myc and cyclin D1 was significantly increased. Consistently, p,p'-DDE-induced cell proliferation along with upregulated c-Myc and cyclin D1 were impeded by β-catenin siRNA or Gli1 siRNA. In addition, p,p'-DDE was able to activate NADPH oxidase, generate reactive oxygen species (ROS) and reduce GSH content, superoxide dismutase (SOD) and calatase (CAT) activities. Treatment with antioxidants prevented p,p'-DDE-induced cell proliferation and signaling pathways of Wnt/β-catenin and Hedgehog/Gli1. These results indicated that p,p'-DDE promoted colorectal cancer cell proliferation through Wnt/β-catenin and Hedgehog/Gli1 signalings mediated by oxidative stress. The finding suggests an association between p,p'-DDE exposure and the risk of colorectal cancer progression.

The organochlorine p,p'-dichlorodiphenyltrichloroethane induces colorectal cancer growth through Wnt/β-catenin signaling

Dichlorodiphenyltrichloroethane (DDT), an organochlorine pollutant, is associated with several types of cancer. However, the relationship between DDT and colorectal cancer is uncertain. In this study, the impact of p,p'-DDT on colorectal cancer growth was evaluated using both in vitro and in vivo models. Our results indicated that the proliferation of human colorectal adenocarcinoma DLD1 cells was significantly promoted after exposed to low concentrations of p,p'-DDT ranging from 10(-12) to 10(-7) M for 96 h. Exposure to p,p'-DDT from 10(-10) to 10(-8) M led to upregulation of phospho-GSK3β (Ser9), β-catenin, c-Myc and cyclin D1 in DLD1 cells. RNA interference of β-catenin inhibited the proliferation of DLD1 cells stimulated by p,p'-DDT. Inhibiting of estrogen receptors (ERs) had no significant effect on the action of p,p'-DDT. Treatment with p,p'-DDT induced production of intracellular reactive oxygen species (ROS) and inhibited superoxide dismutase (SOD) activity in DLD1 cells. Treatment with N-acetyl-L-cysteine (NAC), a ROS inhibitor, suppressed the induction of Wnt/β-catenin signaling and DLD1 cell proliferation by p,p'-DDT. Moreover, in a mouse xenograft model, 5 nmol/kg p,p'-DDT resulted in increased tumor size, oxidative stress and Wnt/β-catenin signaling. These results indicated that low concentrations of p,p'-DDT promoted colorectal cancer growth through Wnt/β-catenin signaling, which was mediated by oxidative stress. The finding suggests an association between low concentrations of p,p'-DDT exposure and colorectal cancer progression.

Miniprobe endoscopic ultrasonography has limitations in determining the T stage in early colorectal cancer

Background/Aims

Mini-probe endoscopic ultrasonography (mEUS) is a useful diagnostic tool for accurate assessment of tumor invasion. The aim of this study was to estimate the accuracy of mEUS in patients with early colorectal cancer (ECC).

Methods

Ninety lesions of ECC underwent mEUS for pre-treatment staging. We divided the lesions into either the mucosal group or the submucosal group according to the mEUS findings. The histological results of the specimens were compared with the mEUS findings.

Results

The overall accuracy for assessing the depth of tumor invasion (T stage) was 84.4% (76/90). The accuracy of mEUS was significantly lower for submucosal lesions compared to mucosal lesions (p=0.003) and it was lower for large tumors (≥2 cm) (p=0.034). The odds ratios of large tumors and submucosal tumors affecting the accuracy of T staging were 3.46 (95% confidence interval [CI], 1.05 to 11.39) and 6.25 (95% CI, 1.85 to 25.14), respectively. When submucosal tumors were combined with large size, the odds ratio was 14.67 (95% CI, 1.46 to 146.96).

Conclusions

The overall accuracy of T stage determination with mEUS was considerably high in patients with ECC; however, the accuracy decreased when tumor size was >2 cm or the tumor had invaded the submucosal layer.

Cholesterol metabolism and colorectal cancers

Colorectal cancer (CRC) is primarily a lifestyle disease of the western world. As such it can be likened to cardiovascular disease and indeed it shares many of the same risk factors. It is therefore perhaps unsurprising that cholesterol metabolism and colorectal cancer are also intricately linked. Many of the initial studies suggesting a link between dietary cholesterol, blood cholesterol levels and cholesterol lowering drugs were performed more than a decade ago. The most recent insights in this field are the result of meta-analyses, advances in pharmacogenetics and the new field of molecular pathological epidemiology. This review summarises the current evidence linking cholesterol metabolism with colorectal cancer including the suggested underlying molecular causes and the implications for colorectal cancer prevention.

Colorectal cancer mortality and industrial pollution in Spain

Background

Records kept as a result of the implementation of Integrated Pollution Prevention and Control (IPPC) and the European Pollutant Release and Transfer Register (E-PRTR) constitute a public inventory of industries, created by the European Commission, which is a valuable resource for monitoring industrial pollution. Our objective is to ascertain whether there might be excess colorectal cancer mortality among populations residing in the vicinity of Spanish industrial installations that are governed by the IPPC Directive and E-PRTR Regulation and report their emissions to air.

Methods

An ecological study was designed to examine colorectal cancer mortality at a municipal level (8098 Spanish towns), over the period 1997–2006. We conducted an exploratory "near vs. far" analysis to estimate the relative risks (RR) of towns situated at a distance of less than 2 km from industrial installations. The analysis was repeated for each of the 24 industrial groups. RR and their 95% credible/confidence intervals (95%CI) were estimated on the basis of Poisson regression models, using two types of modelling: a) the conditional autoregressive Bayesian model proposed by Besag, York and Mollié, with explanatory variables; and b) a mixed regression model. Integrated nested Laplace approximations were used as a Bayesian inference tool.

Results

Statistically significant RRs were detected in the vicinity of mining industry (RR 1.258; 95%CI 1.082 - 1.463), paper and wood production (RR 1.071; 95%CI 1.007 – 1.140), food and beverage sector (RR 1.069; 95%CI 1.029 - 1.111), metal production and processing installations (RR 1.065; 95% CI 1.011 – 1.123) and ceramics (RR 1.050 ; 95%CI 1.004 – 1.099).

Conclusions

Given the exploratory nature of this study, it would seem advisable to check in other countries or with other designs, if the proximity of industries that emit pollutants into the air could be an added risk factor for colorectal cancer mortality. Nevertheless, some of the differences between men and women observed in the analyses of the industrial groups suggest that there may be a component of occupational exposure, little-studied in the case of cancers of the digestive system.

Correlation between expression of CK20 mRNA in peripheral blood and clinicopathological features and prognosis in patients with colorectal cancer

AIM: To investigate the clinical significance of cytokeratin 20 (CK20) mRNA expression in peripheral venous blood of patients with colorectal carcinoma.

METHODS: The expression of CK20 mRNA was detected by RT-PCR in peripheral venous blood samples from 20 healthy volunteers, 10 patients with colorectal polyps, and 61 patients with colorectal cancer.

RESULTS: The positive rate of CK20 mRNA in peripheral venous blood of patients with colorectal cancer was 41.0% (25/61). CK20 mRNA expression in peripheral venous blood was associated with TNM stage, local lymph node metastasis, distant metastasis, and depth of invasion (all P < 0.05). The expression of CK20 mRNA was not detected in peripheral venous blood of healthy volunteers and patients with colorectal polyps. Seventeen cases died during the follow-up period, of whom 10 had positive expression of CK20 in peripheral blood.

CONCLUSION: CK20 is a specific marker for blood micrometastasis of colorectal cancer. The expression of CK20 mRNA in the blood of patients with colorectal cancer is related with the invasion and metastasis of colorectal cancer. Detection of CK20 mRNA in peripheral blood seems to be of relevance for prognosis in colorectal cancer.

Anatomical versus nonanatomical resection of colorectal liver metastases: a meta-analysis

PURPOSE

The purpose of the study was to compare anatomical resection (AR) versus nonanatomical resection (NAR) for colorectal liver metastases (CLM) with respect to perioperative and oncological outcomes.

METHODS

Literature search was performed to identify comparative studies reporting outcomes for both AR and NAR for CLM. Pooled odds ratios (OR) and weighted mean differences (WMD with 95% confidence intervals (95% CI) were calculated using either the fixed effects model or random effects model.

RESULTS

Seven nonrandomized controlled studies matched the selection criteria and reported on 1,662 subjects, of whom 989 underwent AR, and 673 underwent NAR for CLM. Compared with the perioperative results, NAR reduced the operation time (WMD, 0.39; 95% CI, 1.97-79.17) and blood transfusion requirement (OR, 2.98; 95% CI, 1.87-4.74), whereas postoperative morbidity and mortality were similar between the two groups. With respect to oncologic outcomes, there was no significant difference in surgical margins, overall survival and disease-free survival between the two groups.

CONCLUSIONS

NAR is a safe procedure for CLM and does not compromise oncological outcomes. However, the findings have to be carefully interpreted due to the lower level of evidence.

Radiofrequency ablation vs hepatic resection for solitary colorectal liver metastasis: A meta-analysis

AIM: To evaluate the comparative therapeutic efficacy of radiofrequency ablation (RFA) and hepatic resection (HR) for solitary colorectal liver metastases (CLM).

METHODS: A literature search was performed to identify comparative studies reporting outcomes for both RFA and HR for solitary CLM. Pooled odds ratios (OR) with 95% confidence intervals (95% CI) were calculated using either the fixed effects model or random effects model.

RESULTS: Seven nonrandomized controlled trials studies were included in this analysis. These studies included a total of 847 patients: 273 treated with RFA and 574 treated with HR. The 5 years overall survival rates in the HR group were significantly better than those in the RFA group (OR: 0.41, 95% CI: 0.22-0.90, P = 0.008). RFA had a higher rate of local intrahepatic recurrence compared to HR (OR: 4.89, 95% CI: 1.73-13.87, P = 0.003). No differences were found between the two groups with respect to postoperative morbidity and mortality.

CONCLUSION: HR was superior to RFA in the treatment of patients with solitary CLM. However, the findings have to be carefully interpreted due to the lower level of evidence.

Multiparameter analysis of cellular immunity in patients with colorectal cancer

AIM: To compare the proportions of CD4⁺, CD8⁺ T cells, NK cells, B cells, and CD4⁺CD25^HighCD127^low Treg cells and Th/Treg ratio in the peripheral blood of patients with colorectal cancer and healthy controls to investigate the immune status in patients with colorectal cancer.

METHODS: Flow cytometry was used to analyze the proportions of CD4⁺, CD8⁺ T cells, NK cells, B cells, and CD4⁺CD25^HighCD127^low Treg cells and Th/Treg ratio in the peripheral blood from 100 patients with non-metastatic colorectal cancer, 100 patients with metastatic colorectal cancer, and 100 healthy controls. One-way ANOVA was used to study the changes in the above immunity parameters.

RESULTS: The proportion of CD4⁺CD25^HighCD127^low Treg cells was significantly higher in patients with metastatic colorectal cancer than in health controls and patients with non-metastatic colorectal cancer (7.72% ± 2.20% vs 6.08% ± 1.47%, 5.91% ± 1.55%, both P < 0.05), while that of CD4⁺ T cells was statistically lower in patients with metastatic colorectal cancer than in the other two groups of subjects (34.04% ± 8.71% vs 37.83% ± 7.62%, 37.68% ± 8.89%, both P < 0.05). The Th/Treg ratio was also significantly lower in patients with metastatic colorectal cancer than in health controls and patients with non-metastatic colorectal cancer (4.70 ± 1.72 vs 6.47 ± 2.54, 6.81 ± 4.09, both P < 0.05). There were no statistical differences in the proportions of CD8⁺ T cells, NK cells and B cells between patients with colorectal cancer and healthy controls.

CONCLUSION: Abnormal immune status was observed in patients with metastatic colorectal cancer.