Smoking and Risk of Colorectal Cancer Sub-Classified by Tumor-Infiltrating T Cells

Identification of potential mediators of the relationship between body mass index and colorectal cancer: a Mendelian randomization analysis

BACKGROUND

Colorectal cancer (CRC) is the third-most-common cancer worldwide and its rates are increasing. Elevated body mass index (BMI) is an established risk factor for CRC, although the molecular mechanisms behind this association remain unclear. Using the Mendelian randomization (MR) framework, we aimed to investigate the mediating effects of putative biomarkers and other CRC risk factors in the association between BMI and CRC.

METHODS

We selected as mediators biomarkers of established cancer-related mechanisms and other CRC risk factors for which a plausible association with obesity exists, such as inflammatory biomarkers, glucose homeostasis traits, lipids, adipokines, insulin-like growth factor 1 (IGF1), sex hormones, 25-hydroxy-vitamin D, smoking, physical activity (PA) and alcohol consumption. We used inverse-variance weighted MR in the main univariable analyses and performed sensitivity analyses (weighted-median, MR-Egger, Contamination Mixture). We used multivariable MR for the mediation analyses.

RESULTS

Genetically predicted BMI was positively associated with CRC risk [odds ratio per SD (5 kg/m2) = 1.17, 95% CI: 1.08-1.24, P-value = 1.4 × 10-5] and robustly associated with nearly all potential mediators. Genetically predicted IGF1, fasting insulin, low-density lipoprotein cholesterol, smoking, PA and alcohol were associated with CRC risk. Evidence for attenuation was found for IGF1 [explained 7% (95% CI: 2-13%) of the association], smoking (31%, 4-57%) and PA (7%, 2-11%). There was little evidence for pleiotropy, although smoking was bidirectionally associated with BMI and instruments were weak for PA.

CONCLUSIONS

The effect of BMI on CRC risk is possibly partly mediated through plasma IGF1, whereas the attenuation of the BMI-CRC association by smoking and PA may reflect confounding and shared underlying mechanisms rather than mediation.

Effect of smoking-related features and 731 immune cell phenotypes on esophageal cancer: a two-sample and mediated Mendelian randomized study

Introduction

Numerous observational studies have indicated that smoking is a substantial risk factor for esophageal cancer. However, there is a shortage of research that delves into the specific causal relationship and potential mediators between the two. Our study aims to validate the correlation between smoking-related traits and esophageal cancer while exploring the possible mediating effects of immune factors.

Methods

Initially, we conducted bidirectional univariate Mendelian Randomization (MR) analyses to forecast the causal effects linking smoking-related traits and esophageal cancer. Subsequently, we employed a two-step MR analysis to scrutinize immune cell phenotypes that could mediate these effects. Finally, the coefficient product method was employed to determine the precise mediating impact. Additionally, we have refined our sensitivity analysis to ensure the reliability of the outcomes.

Results

After analysis, Smoking status: Never had a significant negative association with the incidence of esophageal cancer (inverse-variance weighted (IVW) method, p=1.82e-05, OR=0.10, 95%CI=0.04~0.29). Ever smoked (IVW, p=1.49e-02, OR=4.31, 95%CI=1.33~13.94) and Current tobacco smoking (IVW, p=1.49e-02, OR=4.31, 95%CI=1.33~13.94) showed the promoting effect on the pathogenesis of esophageal cancer. Through further examination, researchers discovered 21 immune cell phenotypes that have a causal relationship with esophageal cancer. After careful screening, two immune cell phenotypes were found to have potential mediating effects. In particular, it was observed that in the case of the preventive effect of Smoking status: Never on esophageal cancer, the absolute count of CD62L plasmacytoid dendritic cells mediated a reduction of 4.21%, while the mediating effect of CD27 in CD20-CD38-B cells was -4.12%. In addition, sensitivity analyses did not reveal significant heterogeneity or level pleiotropy.

Conclusion

The study provides new evidence for the causal relationship between smoking-related features and esophageal cancer and proposes immune factors with potential mediating effects. However, this finding needs to be further demonstrated by more extensive clinical studies.

Dietary Patterns and Lifestyle Factors Associated with the Risk of Colorectal Cancer: A Hospital-Based Case-Control Study among Malaysians

Background

This study aimed to examine the association between dietary patterns, lifestyle factors, and colorectal cancer (CRC) risk among the Malaysian population.

Methods

We recruited 100 patients and 100 controls from two selected government hospitals. Principal component analysis was used to identify dietary patterns using a 123-item semiquantitative food frequency questionnaire. Tobacco smoking and alcohol consumption questionnaires were modified from the WHO STEPS Survey questionnaire. Physical activity levels were assessed using the revised Global Physical Activity questionnaire. Associations between dietary patterns, lifestyle factors and CRC risk were assessed using logistic regression with SPSS version 24.0.

Results

Three dietary patterns were derived from factor analysis: i) vegetables; ii) meat, seafood and processed food; and iii) grains and legumes. High vegetable diet intake was independently and significantly associated with an 81% decreased risk of CRC (odds ratio [OR]: 0.19; 95% confidence interval [CI]: 0.08, 0.46). Both recreational-related physical activity (OR: 2.04; 95% CI: 1.14, 3.64) and vigorous physical activity (OR: 2.06; 95% CI: 1.13, 3.74) are significantly associated with decreased risk of CRC. Increasing the number of cigarettes smoked (≥ 16 cigarettes) per day significantly increased the odds of developing CRC (OR: 2.58; 95% CI: 1.95, 6.75). The duration of alcohol consumption cessation was inversely associated with CRC risk (OR: 2.52; 95% CI: 2.30, 10.57).

Conclusion

The protective effects of a fruit and vegetable diet, and a healthy lifestyle can be used to develop interventions that help reduce the risk of CRC in the Malaysian population.

Clinical significance of Bacteroides fragilis as a potential prognostic factor in colorectal cancer

INTRODUCTION

Bacteroides fragilis (B. fragilis) is considered to act in an anti-inflammatory manner on the intestinal tract. On the contrary, enterotoxigenic B. fragilis (ETBF), a subtype of B. fragilis, produces an enterotoxin (BFT; B. fragilis toxin), leading to asymptomatic chronic infections and colonic tumor formation. However, the impact of B. fragilis and ETBF on the clinical outcome of colorectal cancer (CRC) remains unclear. We aim to assess whether their presence affects the outcome in patients with CRC after curative resection.

METHODS

We obtained 197 pairs of matched formalin-fixed paraffin-embedded samples from cancerous and adjacent non-cancerous tissues of patients with pathological stage (pstage) II and III CRC after curative resection. The presence of B. fragilis and ETBF were estimated using real-time polymerase chain reaction, and recurrence-free survival (RFS) and overall survival (OS) of the patients were analyzed.

RESULTS

16S rRNA for B. fragilis and bft DNA were detected in 120 (60.9%) and 12 (6.1%) of the 197 patients, respectively. B. fragilis-positive patients had better RFS than B. fragilis-negative patients, although that was not statistically significant. In subgroup analysis, better outcomes on RFS were observed in the presence of B. fragilis in pstage II and left-sided CRC. The association of B. fragilis positivity on OS was accentuated in the depth of T4 subgroup. No significant differences were observed in RFS and OS between ETBF and non-toxigenic B. fragilis.

CONCLUSIONS

Our findings suggest that the presence of B. fragilis is associated with better outcomes in patients with pstage II and III CRC after curative resection.

Dissecting the pathogenic effects of smoking and its hallmarks in blood DNA methylation on colorectal cancer risk

BACKGROUND

Tobacco smoking is suggested as a risk factor for colorectal cancer (CRC), but the complex relationship and the potential pathway are not fully understood.

METHODS

We performed two-sample Mendelian randomisation (MR) analyses with genetic instruments for smoking behaviours and related DNA methylation in blood and summary-level GWAS data of colorectal cancer to disentangle the relationship. Colocalization analyses and prospective gene-environment interaction analyses were also conducted as replication.

RESULTS

Convincing evidence was identified for the pathogenic effect of smoking initiation on CRC risk and suggestive evidence was observed for the protective effect of smoking cessation in the univariable MR analyses. Multivariable MR analysis revealed that these associations were independent of other smoking phenotypes and alcohol drinking. Genetically predicted methylation at CpG site cg17823346 [ZMIZ1] were identified to decrease CRC risk; while genetically predicted methylation at cg02149899 would increase CRC risk. Colocalization and gene-environment interaction analyses added further evidence to the relationship between epigenetic modification at cg17823346 [ZMIZ1] as well as cg02149899 and CRC risk.

DISCUSSION

Our study confirms the significant association between tobacco smoking, DNA methylation and CRC risk and yields a novel insight into the pathogenic effect of tobacco smoking on CRC risk.

Association of cigarette smoking with risk of colorectal cancer subtypes classified by gut microbiota

INTRODUCTION

Both cigarette smoking and gut microbiota play important roles in colorectal carcinogenesis. We explored whether the association between smoking and colorectal cancer (CRC) risk varies by gut microbial enterotypes and how smoking-related enterotypes promote colorectal carcinogenesis.

METHODS

A case-control study was conducted. Fecal microbiota was determined by 16S rDNA sequencing. The cases with CRC or adenoma were subclassified by gut microbiota enterotypes. Multivariate analyses were used to test associations between smoking and the odds of colorectal neoplasm subtypes. Mann-Whitney U tests were used to find differential genera, genes, and pathways between the subtypes.

RESULTS

Included in the study were 130 CRC patients (type I: n=77; type II: n=53), 120 adenoma patients (type I: n=66; type II: n=54), and 130 healthy participants. Smoking increased the odds for type II tumors significantly (all p for trend <0.05) but not for type I tumors. The associations of smoking with increased odds of colorectal neoplasm significantly differed by gut microbiota enterotypes (p<0.05 for heterogeneity). An increase in carcinogenic bacteria (genus Escherichia shigella) and a decrease in probiotics (family Lachnospiraceae and Ruminococcaceae) in type II tumors may drive disease progression by upregulating oncogenic signaling pathways and inflammatory/oxidative stress response pathways, as well as protein phospholipase D1/2, cytochrome C, and prostaglandin-endoperoxide synthase 2 expression.

CONCLUSIONS

Smoking was associated with a higher odds of type II colorectal neoplasms but not type I tumors, supporting a potential role for the gut microbiota in mediating the association between smoking and colorectal neoplasms.

A common cancer at an uncommon age

The etiology of early-onset colorectal cancer needs to be understood to tackle rising incidence.

Genome-wide Interaction Study with Smoking for Colorectal Cancer Risk Identifies Novel Genetic Loci Related to Tumor Suppression, Inflammation, and Immune Response

BACKGROUND

Tobacco smoking is an established risk factor for colorectal cancer. However, genetically defined population subgroups may have increased susceptibility to smoking-related effects on colorectal cancer.

METHODS

A genome-wide interaction scan was performed including 33,756 colorectal cancer cases and 44,346 controls from three genetic consortia.

RESULTS

Evidence of an interaction was observed between smoking status (ever vs. never smokers) and a locus on 3p12.1 (rs9880919, P = 4.58 × 10-8), with higher associated risk in subjects carrying the GG genotype [OR, 1.25; 95% confidence interval (CI), 1.20-1.30] compared with the other genotypes (OR <1.17 for GA and AA). Among ever smokers, we observed interactions between smoking intensity (increase in 10 cigarettes smoked per day) and two loci on 6p21.33 (rs4151657, P = 1.72 × 10-8) and 8q24.23 (rs7005722, P = 2.88 × 10-8). Subjects carrying the rs4151657 TT genotype showed higher risk (OR, 1.12; 95% CI, 1.09-1.16) compared with the other genotypes (OR <1.06 for TC and CC). Similarly, higher risk was observed among subjects carrying the rs7005722 AA genotype (OR, 1.17; 95% CI, 1.07-1.28) compared with the other genotypes (OR <1.13 for AC and CC). Functional annotation revealed that SNPs in 3p12.1 and 6p21.33 loci were located in regulatory regions, and were associated with expression levels of nearby genes. Genetic models predicting gene expression revealed that smoking parameters were associated with lower colorectal cancer risk with higher expression levels of CADM2 (3p12.1) and ATF6B (6p21.33).

CONCLUSIONS

Our study identified novel genetic loci that may modulate the risk for colorectal cancer of smoking status and intensity, linked to tumor suppression and immune response.

IMPACT

These findings can guide potential prevention treatments.

Lifetime Exposure to Cigarette Smoke and Risk of Ovarian Cancer by T-cell Tumor Immune Infiltration

BACKGROUND

Exposure to cigarette smoke, particularly in early life, is modestly associated with ovarian cancer risk and may impact systemic immunity and the tumor immune response. However, no studies have evaluated whether cigarette smoke exposure impacts the ovarian tumor immune microenvironment.

METHODS

Participants in the Nurses' Health Study (NHS) and NHSII reported on early life exposure to cigarette smoke and personal smoking history on questionnaires (n = 165,760). Multiplex immunofluorescence assays were used to measure markers of T cells and immune checkpoints in tumor tissue from 385 incident ovarian cancer cases. We used Cox proportional hazards models to evaluate HRs and 95% confidence intervals (CI) for developing ovarian tumors with a low (<median) or high (≥median) immune cell percentage by cigarette exposure categories.

RESULTS

Women exposed versus not to cigarette smoke early in life had a higher risk of developing ovarian cancer with low levels of T cells overall (CD3+: HR: 1.54, 95% CI: 1.08-2.20) and recently activated cytotoxic T cells (CD3+CD8+CD69+: HR: 1.45, 95% CI: 1.05-2.00). These findings were not statistically significant at the Bonferroni-corrected P value of 0.0083. Adult smoking was not significantly associated with tumor immune markers after Bonferroni correction.

CONCLUSIONS

These results suggest early life cigarette smoke exposure may modestly increase risk of developing ovarian tumors with low abundance of total T cells and recently activated cytotoxic T cells.

IMPACT

Future research should focus on understanding the impact of exposures throughout the life course on the ovarian tumor immune microenvironment.

Proceedings of the fifth international Molecular Pathological Epidemiology (MPE) meeting

Cancer heterogeneities hold the key to a deeper understanding of cancer etiology and progression and the discovery of more precise cancer therapy. Modern pathological and molecular technologies offer a powerful set of tools to profile tumor heterogeneities at multiple levels in large patient populations, from DNA to RNA, protein and epigenetics, and from tumor tissues to tumor microenvironment and liquid biopsy. When coupled with well-validated epidemiologic methodology and well-characterized epidemiologic resources, the rich tumor pathological and molecular tumor information provide new research opportunities at an unprecedented breadth and depth. This is the research space where Molecular Pathological Epidemiology (MPE) emerged over a decade ago and has been thriving since then. As a truly multidisciplinary field, MPE embraces collaborations from diverse fields including epidemiology, pathology, immunology, genetics, biostatistics, bioinformatics, and data science. Since first convened in 2013, the International MPE Meeting series has grown into a dynamic and dedicated platform for experts from these disciplines to communicate novel findings, discuss new research opportunities and challenges, build professional networks, and educate the next-generation scientists. Herein, we share the proceedings of the Fifth International MPE meeting, held virtually online, on May 24 and 25, 2021. The meeting consisted of 21 presentations organized into the three main themes, which were recent integrative MPE studies, novel cancer profiling technologies, and new statistical and data science approaches. Looking forward to the near future, the meeting attendees anticipated continuous expansion and fruition of MPE research in many research fronts, particularly immune-epidemiology, mutational signatures, liquid biopsy, and health disparities.

The Burden of Early-Onset Colorectal Cancer and Its Risk Factors from 1990 to 2019: A Systematic Analysis for the Global Burden of Disease Study 2019

Simple Summary

In this cross-sectional study, the global incidence, death, and DALY rates of early-onset colorectal cancer (CRC) increased from 1990 to 2019, with large variations in the regional and national levels. A low-milk or low-calcium diet and alcohol use were the leading possible risk factors in 2019. The importance of high body mass index and high fasting plasma glucose increased among both males and females from 1990 to 2019, while the importance of smoking and a low-fiber diet decreased among both sexes, but especially among females. These findings provide policymakers with an accurate quantification of the burden of early-onset CRC, and may help to identify and target high-risk individuals to mitigate the burden of early-onset CRC.

Abstract

Background: The incidence of early-onset colorectal cancer (CRC) diagnosed before age 50 has been increasing over the past decades. Hence, we examined the global, regional, and national burden of early-onset CRC and its risk factors from 1990 to 2019. Methods: Using data from the Global Burden of Disease (GBD) Study 2019, we reported the incidence, deaths, and disability-adjusted life-years (DALYs) attributable to the risk factors of early-onset CRC. All estimates were reported with 95% uncertainty intervals (UIs). Results: The global numbers of early-onset CRC for incidence, deaths, and DALYs in 2019 were 225,736 (95% UI, 207,658 to 246,756), 86,545 (80,162 to 93,431), and 4,259,922 (3,942,849 to 4,590,979), respectively. Despite large variations at the regional and national levels, the global incidence rate, death rate, and DALY rate increased from 1990 to 2019. Diets low in milk, diets low in calcium, and alcohol use were the leading risk factors in 2019. From 1990 to 2019, a high body mass index and high fasting plasma glucose ranked remarkably higher among males and females, while smoking and diets low in fiber ranked lower among both sexes, with a more profound change among females. Conclusions: Despite large variations in regional and national levels, the global incidence rate, death rate, and DALY rate increased during the past three decades. These findings may provide policymakers with an accurate quantification of the burden of early-onset CRC and targeted identification of those most at risk to mitigate the burden of early-onset CRC.

Cancer as microenvironmental, systemic and environmental diseases: opportunity for transdisciplinary microbiomics science

Cancer is generally regarded as a localised disease, with the well-established role of the tumour microenvironment. However, the realm of cancer goes beyond the tumour microenvironment, and cancer should also be regarded as a systemic and environmental disease. The exposome (ie, the totality of exposures), which encompasses diets, supplements, smoking, alcohol, other lifestyle factors, medications, etc, likely alters the microbiome (inclusive of bacteria, viruses, archaea, fungi, parasites, etc) and immune system in various body sites and influences tumour phenotypes. The systemic metabolic/inflammatory status, which is likely influenced by exposures and intestinal physiological changes, may affect tissue microenvironment of colorectum and any other organs. Germline genomic factors can modify disease phenotypes via gene-by-environment interactions. Although challenges exist, it is crucial to advance not only basic experimental research that can analyse the effects of exposures, microorganisms and microenvironmental components on tumour evolution but also interdisciplinary human population research that can dissect the complex pathogenic roles of the exposome, microbiome and immunome. Metagenomic, metatranscriptomic and metabolomic analyses should be integrated into well-designed population research combined with advanced methodologies of artificial intelligence and molecular pathological epidemiology. Ideally, a prospective cohort study design that enables biospecimen (such as stool) collection before disease detection should be considered to address reverse causation and recall biases. Robust experimental and observational research together can provide insights into dynamic interactions between environmental exposures, microbiota, tumour and immunity during carcinogenesis processes, thereby helping us develop precision prevention and therapeutic strategies to ultimately reduce the cancer burden.

Integrative genomic analysis reveals low T-cell infiltration as the primary feature of tobacco use in HPV-positive oropharyngeal cancer

Although tobacco use is an independent adverse prognostic feature in HPV(+) oropharyngeal squamous cell carcinoma (OPSCC), the biologic features associated with tobacco use have not been systematically investigated. We characterized genomic and immunologic features associated with tobacco use through whole exome sequencing, mRNA hybridization, and immunohistochemical staining in 47 HPV(+) OPSCC tumors. Low expression of transcripts in a T cell-inflamed gene expression profile (TGEP) was associated with tobacco use at diagnosis and lower overall and disease-free survival. Tobacco use was associated with an increased proportion of T > C substitutions and a lower proportion of expected mutational signatures, but not with increases in mutational burden or recurrent oncogenic mutations. Our findings suggest that rather than increased mutational burden, tobacco's primary and clinically relevant association in HPV(+) OPSCC is immunosuppression of the tumor immune microenvironment. Quantitative assays of T cell infiltration merit further study as prognostic markers in HPV(+) OPSCC.

A high density of PD-L1-expressing immune cells is significantly correlated with favorable disease free survival in nonmetastatic colorectal cancer

The impact of immune cells (ICs) expressing various markers remains poorly understood in nonmetastatic colorectal cancer patients who have undergone colectomy. Here, we aimed to clarify the correlation between IC density and clinical parameters and survival.Programmed death protein-1 (PD-1), programmed cell death protein ligand-1 (PD-L1), clusters of differentiation (CD)-3, CD-8, and CD45RO immunostaining was performed for 421 patients using tissue microarray and automatic counting. Tumor stroma area immune density was assessed in comparison to clinical histological factors and surgical outcomes.High-density CD-8 expression was significantly associated with current smoking habits or a smoking history (P = .006). High-density of PD-1 expression was correlated with Lynch syndrome patients (P < .001) and with patients who did not consume alcohol (P = .034). A significant decrease in CR45RO expression density was associated with aging (P = .002 and r = -0.014), and high-density CD-3, CD-8, and PD-1 expression was significantly associated with right colon tumor location (P < .001). High CD-3 and PD-L1 expression was significantly associated with early tumor T-staging (P = .018 and P = .002). High-density PD-1 expression was significantly correlated with mucinous type adenocarcinoma (P = .027) and poor differentiation (P < .001). For treatment outcomes, multivariate analysis confirmed that patients exhibiting high-density PD-L1 expression possessed significantly longer disease free survival (adjusted hazard ratio: 0.752, 95% confidence interval [CI]: 0.61-0.92, P = .006) and overall survival (adjusted hazard ratio: 0.872, 95% CI: 0.75-1.91, P = .064)Significantly varied density in IC subsets was related to distinct demographic or clinic-histological factors. The presence of high-density PD-L1-expressing ICs is an independent favorable prognostic factor for disease free survival and overall survival among stage I to III colorectal cancer patients.

Smoking and Incidence of Colorectal Cancer Subclassified by Tumor-Associated Macrophage Infiltrates

BACKGROUND

Biological evidence indicates that smoking can influence macrophage functions and polarization, thereby promoting tumor evolution. We hypothesized that the association of smoking with colorectal cancer incidence might differ by macrophage infiltrates.

METHODS

Using the Nurses' Health Study and the Health Professionals Follow-up Study, we examined the association of smoking with incidence of colorectal cancer subclassified by macrophage counts. Multiplexed immunofluorescence (for CD68, CD86, IRF5, MAF, and MRC1 [CD206]) combined with digital image analysis and machine learning was used to identify overall, M1-polarized, and M2-polarized macrophages in tumor. We used inverse-probability-weighted multivariable Cox proportional hazards regression models to control for potential confounders and selection bias because of tissue data availability. All statistical tests were 2-sided.

RESULTS

During follow-up of 131 144 participants (3 648 370 person-years), we documented 3092 incident colorectal cancer cases, including 871 cases with available macrophage data. The association of pack-years smoked with colorectal cancer incidence differed by stromal macrophage densities (Pheterogeneity = .003). Compared with never smoking, multivariable-adjusted hazard ratios (95% confidence interval) for tumors with low macrophage densities were 1.32 (0.97 to 1.79) for 1-19 pack-years, 1.31 (0.92 to 1.85) for 20-39 pack-years, and 1.74 (1.26 to 2.41) for 40 or more pack-years (Ptrend = .004). In contrast, pack-years smoked was not statistically significantly associated with the incidence of tumors having intermediate or high macrophage densities (Ptrend > .009, with an α level of .005). No statistically significant differential association was found for colorectal cancer subclassified by M1-like or M2-like macrophages.

CONCLUSIONS

The association of smoking with colorectal cancer incidence is stronger for tumors with lower stromal macrophage counts. Our findings suggest an interplay of smoking and macrophages in colorectal carcinogenesis.

Polymorphisms in IL-17A Gene and Susceptibility of Colorectal Cancer in Bangladeshi Population: A Case-Control Analysis

OBJECTIVE

Interleukin-17A (IL-17A) genetic polymorphisms are associated with multiple cancer types, including colorectal cancer (CRC). However, no previous study was performed in the Bangladeshi population to evaluate the association. Our study aimed to find the association between two IL-17A variants (rs10484879 C/A and rs3748067 G/A) and susceptibility of CRC.

METHODS AND MATERIALS

This retrospective case-control study comprised 292 CRC patients and 288 age, sex, and BMI matched healthy volunteers. Genotyping of both variants was done by the tetra-primer ARMS-PCR method, and the results were analyzed by the SPSS software package (version-25.0).

RESULTS

Logistic regression analysis indicated that in case of IL-17A rs10484879 polymorphism, AC and AA genotype carriers showed 2.44- and 3.27-times significantly increased risk for CRC development (OR = 2.44, P = .0008 and OR = 3.27, P = .0133, individually). A significant association was also observed for AC + AA genotype (OR = 2.58, P = .0001). Again, over-dominant and allelic model revealed statistically significant link to CRC risk (OR = 2.13, P = .0035 and OR = 2.22, P = .001). For rs3748067 polymorphism, AG and AA genotype carriers showed 2.30- and 2.45-times enhanced risk for CRC (OR = 2.30, P = .005 and OR = 2.45, P = .031). A statistically significant association was also observed for AG + AA genotype (OR = 2.35, P = .001), over-dominant model (OR = 2.05, P = .014), and allelic model (OR = 2.11, P = .0004).

CONCLUSION

This study highlights that IL-17A rs10484879 and rs3748067 polymorphisms may be associated with CRC development. However, further functional research with larger samples may reveal more statistically significant outcomes.

Impacts of Cigarette Smoking on the Tumor Immune Microenvironment in Esophageal Squamous Cell Carcinoma

Objective: Cigarette smoking is a carcinogenic factor for esophageal cancer and evidence also indicates its effects on tumor microenvironment in patients with esophageal squamous cell carcinoma (ESCC). Materials and Methods: In our study, we demonstrated nine immune infiltrating cells and markers in non-smokers and smokers of 189 non-drinking ESCC patients with multiplex fluorescent immunohistochemistry (mflHC) staining and multispectral imaging. The impacts of cigarette smoking on tumor microenvironment and patient prognosis were also analyzed. Results: Among 189 ESCC patients of non-drinker, 86 patients was current smokers, while 34 males and 59 females were non-smokers and 10 former-smokers. Among 34 male non-smokers and 83 smokers, distinct immune infiltrating cells, with increased DCs in stromal regions (P=0.033), elevated infiltration of Treg cells in intraepithelial regions (P=0.010) and reduced activate cytotoxic T lymphocytes (aCTLs) in both intraepithelial (P=0.021) and stromal regions (P=0.017), were observed in tumor specimens of smoking males, implying an immune suppressed response during cigarette smoke exposure. For smoking characters, the level of stromal tumor-associated macrophages (TAMs) infiltration was correlated with smoking year after age adjusted (r_s =0.352, P=0.002). Though cigarette smoking did not alter the expression of programmed death ligand 1 (PD-L1) in epithelial cells or TAMs in tumor specimens, higher expression of PD-L1 predicted a worse survival in non-smokers but not smokers. Conclusions: Our findings indicated smoking may impair T cell-mediated immune response and supported the possible impacts of cigarette smoking in PD-L1 related research and therapy of ESCC.

Global colorectal cancer burden in 2020 and projections to 2040

As the third most common malignancy and the second most deadly cancer, colorectal cancer (CRC) induces estimated 1.9 million incidence cases and 0.9 million deaths worldwide in 2020. The incidence of CRC is higher in highly developed countries, and it is increasing in middle- and low-income countries due to westernization. Moreover, a rising incidence of early-onset CRC is also emerging. The large number of CRC cases poses a growing global public health challenge. Raising awareness of CRC is important to promote healthy lifestyle choices, novel strategies for CRC management, and implementation of global screening programs, which are critical to reducing CRC morbidity and mortality in the future. CRC is a heterogeneous disease, and its subtype affiliation influences prognosis and therapeutic response. An accurate CRC subtype classification system is of great significance for basic research and clinical outcome. Here, we present the global epidemiology of CRC in 2020 and projections for 2040, review the major CRC subtypes to better understand CRC molecular basis, and summarize current risk factors, prevention, and screening strategies for CRC.

Evaluation of common genetic variants in vitamin E-related pathway genes and colorectal cancer susceptibility

Vitamin E is effective for preventing the risk of cancer. However, few studies have elucidated the mechanism of vitamin E in cancer occurrence. Herein, we aimed to identify the genetic variants in vitamin E-related pathway genes associated with colorectal cancer risk. We applied logistic regression models to assess the association between single-nucleotide polymorphisms (SNPs) in vitamin E-related pathway genes and colorectal cancer risk in the Chinese and European population. The false discovery rate (FDR) method was used to correct multiple comparisons. The mRNA and protein expression analysis were evaluated in public database and in-house RNA-Seq data. SCARB1 rs73227586 was identified significantly increased risk of colorectal cancer in the Chinese population (odd ratio (OR) = 1.46, 95% confidence interval (CI) = 1.22-1.75, P = 2.99 × 10^-5). This finding was further validated in the European population (OR = 1.11, 95% CI = 1.02-1.20, P = 1.44 × 10^-2). Additionally, the mRNA and protein expression of SCARB1 were markedly up-regulated in colorectal tumor tissues. Moreover, rs73227586 T allele could increase the minimum free energy (MFE) and weaken binding ability to transcription factor ELL2. Our findings indicated that SCARB1 may play a carcinogenic role in colorectal cancer. Genetic variants in vitamin E-related pathway genes may concern to be predictors of colorectal cancer risk.

Prospective Analyses of Lifestyle Factors Related to Energy Balance and Ovarian Cancer Risk by Infiltration of Tumor-Associated Macrophages

BACKGROUND

Lifestyle factors related to energy balance have been associated with ovarian cancer risk and influence the tumor immune microenvironment, including tumor-associated macrophages (TAM). However, no studies have assessed whether these factors differentially impact ovarian cancer risk by TAM densities.

METHODS

We conducted a prospective analysis in the Nurses' Health Studies to examine the associations of physical activity, sitting time, and a food-based empirical dietary inflammatory pattern (EDIP) score with invasive epithelial ovarian cancer risk by TAM density assessed by immunohistochemistry. We considered density of CD68 (marker of total TAMs) and CD163 (marker of pro-carcinogenic M2-type TAMs), and their ratios. We used multivariable Cox proportional hazards regression to calculate hazard ratios (HR) and 95% confidence intervals (CI) of exposures with risk of ovarian tumors with high versus low TAMs, including analyses stratified by body mass index.

RESULTS

Analyses included 312 incident ovarian cancer cases with TAM measurements. Physical activity, sitting time, and EDIP score were not differentially associated with ovarian cancer risk by TAM densities (P heterogeneity > 0.05). Among overweight and obese women, higher EDIP score was associated with increased risk of CD163 low-density tumors (HR comparing extreme tertiles, 1.57; 95% CI, 0.88-2.80; P trend = 0.01), but not CD163 high-density tumors (comparable HR, 1.16; 95% CI, 0.73-1.86; P trend = 0.24), though this difference was not statistically significant (P heterogeneity = 0.22).

CONCLUSIONS

We did not observe differential associations between lifestyle factors and ovarian cancer risk by TAM densities.

IMPACT

Future investigations examining the interplay between other ovarian cancer risk factors and the tumor immune microenvironment may help provide insight into ovarian cancer etiology.

Risk of Second Primary Malignancies Based on the Histological Subtypes of Colorectal Cancer

Background: Previous studies have revealed an increased risk of second primary malignancies (SPMs) after colorectal cancer (CRC); however, no previous investigation has quantified differences in the risk of SPMs based on the histological subtypes of first primary CRC.

Methods: Patients diagnosed with first primary CRC between 2000 and 2011 were identified from the Surveillance, Epidemiology, and End Results cancer registries. The patients were divided into three cohorts: classical adenocarcinoma (CA), mucinous adenocarcinoma (MA), and signet-ring cell carcinoma (SRCC). Standardized incidence ratios were calculated to assess the risk of SPMs among the patients.

Results: Overall risk of SPMs was significantly higher among patients with three histological subtypes of CRC than in the general population. The risk of esophagus cancer was significantly increased in SRCC. The risk of small intestine, colon and rectum, and corpus uteri cancers was high in three histological subtypes, with the highest risk observed in SRCC, followed by MA. Increased risks of second stomach, uterus, urinary bladder, kidney, and thyroid cancers were only observed in CA patients, while increased risk of second renal pelvis cancer was limited to MA patients. Furthermore, the high overall risk of SPMs in CA patients persisted regardless of clinicopathological factors. After surgery combined with chemotherapy treatment, CA patients were more prone to developing second small intestine, colon and rectum cancers than those treated with surgery only. A lower second prostate cancer risk was observed in rectal CA patients treated with surgery combined with radiotherapy than in patients treated with surgery only.

Conclusion: The present study revealed that the risk of developing SPMs after CRC varied based on the histological subtypes of the first primary CRC. Although the mechanisms underlying the observed patterns of SPM risk remain unknown, the study provided insights into future cancer surveillance based on the histological subtypes of CRC.

Emerging Role of Immunotherapy for Colorectal Cancer with Liver Metastasis

Colorectal cancer (CRC) is the third most common malignant tumor in the world and the second leading cause of cancer-related deaths, with the liver as the most common site of distant metastasis. The prognosis of CRC with liver metastasis is poor, and most patients cannot undergo surgery. In addition, conventional antitumor approaches such as chemotherapy, radiotherapy, targeted therapy, and surgery result in unsatisfactory outcomes. In recent years, immunotherapy has shown good prospects in the treatment of assorted tumors by enhancing the host's antitumor immune function, and it may become a new effective treatment for liver metastasis of CRC. However, challenges remain in applying immunotherapy to CRC with liver metastasis. This review examines how the microenvironment and immunosuppressive landscape of the liver favor tumor progression. It also highlights the latest research advances in immunotherapy for colorectal liver metastasis and identifies immunotherapy as a treatment regimen with a promising future in clinical applications.

Coffee Intake and Colorectal Cancer Incidence According to T-Cell Response

We hypothesized that the associations between coffee intake and colorectal cancer (CRC) incidence might differ by immune cell densities in CRC tissue. Using the Nurses’ Health Study and the Health Professionals Follow-up Study, we examined the association of coffee intake with incidence of CRC classified by intraepithelial or stromal T-cell subset densities by multiplex immunofluorescence assay for CD3, CD4, CD8, CD45RO (PTPRC), and FOXP3. We applied an inverse probability-weighted Cox proportional hazardsregression model to control for selection bias and potential confounders. During follow-up of 133 924 participants (3 585 019 person-years), we documented 3161 incident CRC cases, including 908 CRC cases with available data on T-cell densities in tumor tissue. The association between coffee intake and CRC was not statistically significantly different by intraepithelial or stroma T-cell subset (P_{heterogeneity} > .38). Hence, there is no sufficient evidence for differential effect of coffee intake on incidence of CRC subtypes classified by T-cell infiltrates.

Smoking Status at Diagnosis and Colorectal Cancer Prognosis According to Tumor Lymphocytic Reaction

Background

Smoking has been associated with worse colorectal cancer patient survival and may potentially suppress the immune response in the tumor microenvironment. We hypothesized that the prognostic association of smoking behavior at colorectal cancer diagnosis might differ by lymphocytic reaction patterns in cancer tissue.

Methods

Using 1474 colon and rectal cancer patients within 2 large prospective cohort studies (Nurses' Health Study and Health Professionals Follow-up Study), we characterized 4 patterns of histopathologic lymphocytic reaction, including tumor-infiltrating lymphocytes (TILs), intratumoral periglandular reaction, peritumoral lymphocytic reaction, and Crohn's-like lymphoid reaction. Using covariate data of 4420 incident colorectal cancer patients in total, an inverse probability weighted multivariable Cox proportional hazards regression model was conducted to adjust for selection bias due to tissue availability and potential confounders, including tumor differentiation, disease stage, microsatellite instability status, CpG island methylator phenotype, long interspersed nucleotide element-1 methylation, and KRAS, BRAF, and PIK3CA mutations.

Results

The prognostic association of smoking status at diagnosis differed by TIL status. Compared with never smokers, the multivariable-adjusted colorectal cancer-specific mortality hazard ratio for current smokers was 1.50 (95% confidence interval = 1.10 to 2.06) in tumors with negative or low TIL and 0.43 (95% confidence interval = 0.16 to 1.12) in tumors with intermediate or high TIL (2-sided P _interaction = .009). No statistically significant interactions were observed in the other patterns of lymphocytic reaction.

Conclusions

The association of smoking status at diagnosis with colorectal cancer mortality may be stronger for carcinomas with negative or low TIL, suggesting a potential interplay of smoking and lymphocytic reaction in the colorectal cancer microenvironment.

[Incidence of Colon Cancer Related to Cigarette Smoking and Alcohol Consumption in Adults with Metabolic Syndrome: Prospective Cohort Study]

PURPOSE

The purpose of this study was to identify the impact of cigarette smoking and alcohol consumption on the incidence of colon cancer in adults with metabolic syndrome.

METHODS

This study employed a longitudinal study design and utilized secondary data drawn from the Korean Genome and Epidemiology Study (KoGES). The data of a sample of 2,327 adults with metabolic syndrome tracked every two years from 2001 to 2014 were used in this study. Statistical data analyses of the frequency, number of cases per 100,000 person-years, log-rank test, Kaplan-Meier curve, and Cox's proportional hazards regression were performed using IBM SPSS statistics version 24.

RESULTS

During the observation period, the number of colon cancer cases was 46, and the total person-years were 252,444. The incidence of colon cancer was higher in current, over 10 pack-year smokers when compared to non-smokers (hazard ratio=3.38, 95% confidence interval=1.09~8.42).

CONCLUSION

Excessive and long-term smoking should be avoided to prevent colon cancer, especially in adults with metabolic syndrome, since it might exacerbate the risk factors of colon cancer. Particularly, health professionals need to provide individualized smoking cessation interventions to those at high risk of colon cancer.

α-Conotoxins Enhance both the In Vivo Suppression of Ehrlich carcinoma Growth and In Vitro Reduction in Cell Viability Elicited by Cyclooxygenase and Lipoxygenase Inhibitors

Several biochemical mechanisms, including the arachidonic acid cascade and activation of nicotinic acetylcholine receptors (nAChRs), are involved in increased tumor survival. Combined application of inhibitors acting on these two pathways may result in a more pronounced antitumor effect. Here, we show that baicalein (selective 12-lipoxygenase inhibitor), nordihydroguaiaretic acid (non-selective lipoxygenase inhibitor), and indomethacin (non-selective cyclooxygenase inhibitor) are cytotoxic to Ehrlich carcinoma cells in vitro. Marine snail α-conotoxins PnIA, RgIA and ArIB11L16D, blockers of α3β2/α6β2, α9α10 and α7 nAChR subtypes, respectively, as well as α-cobratoxin, a blocker of α7 and muscle subtype nAChRs, exhibit low cytotoxicity, but enhance the antitumor effect of baicalein 1.4-fold after 24 h and that of nordihydroguaiaretic acid 1.8-3.9-fold after 48 h of cell cultivation. α-Conotoxin MII, a blocker of α6-containing and α3β2 nAChR subtypes, increases the cytotoxic effect of indomethacin 1.9-fold after 48 h of cultivation. In vivo, baicalein, α-conotoxins MII and PnIA inhibit Ehrlich carcinoma growth and increase mouse survival; these effects are greatly enhanced by the combined application of α-conotoxin MII with indomethacin or conotoxin PnIA with baicalein. Thus, we show, for the first time, antitumor synergism of α-conotoxins and arachidonic acid cascade inhibitors.

Pet ownership and risk of dying from cancer: observation from a nationally representative cohort

We longitudinally examined the relationship between pet ownership and risk of dying from cancer in a nationally representative cohort of 13,725 adults in the Third National Health and Nutrition Examination Survey, 1988-1994. The vital status was followed through 31 December 2010. Women who owned pets (any type) presented one-year shorter survival time (15.88 years) than non-pet owner (16.83 years). A larger difference of survival time was particularly seen in bird owners (13.01 years) compared to non-bird owners (16.82 years). After adjusting for potential confounders, hazard ratio (HR) of dying from cancer associated with any type of pets was 1.08 (95% CI = 0.77-1.50) for men and 1.40 (1.01-1.93) for women. The association in women was presumably driven by owning birds [HR 2.41 (1.34-4.31)] or cats [HR 1.48 (0.97-2.24)]. Keeping birds and cats in the household was associated with an increased risk of dying from cancer, especially in women.

Andrographolide antagonizes the cigarette smoke-induced epithelial-mesenchymal transition and pulmonary dysfunction through anti-inflammatory inhibiting HOTAIR

In cells of the lung surface, cigarette smoke (CS) induces inflammatory and epithelial-mesenchymal transition (EMT), effects that are related to pulmonary dysfunction and Chronic obstructive pulmonary disease (COPD). However, the molecular mechanisms involved remain largely unknown, and potential therapeutic approaches are under development. In the present study, with cell culture and animal studies, we showed that CS exposure causes pulmonary dysfunction and airway remodeling with inflammatory cell infiltration. Consistent with these pulmonary lesions, the inflammatory factors interleukin-6 (IL-6) and interleukin-8 (IL-8) were increased in mice exposed to CS for 4 days. Accordingly, downstream signal transducer and activator of transcription 3 (STAT3) was activated, which up-regulated expression of the lncRNA HOTAIR, and enhancer of zeste homolog 2 (EZH2). In addition, CS exposure led to decreased levels of E-cadherin and to increased N-cadherin, vimentin, and α-SMA, indicating that the EMT was induced in mouse lung tissues. These effects, including increases of IL-6 and HOTAIR, were confirmed in human bronchial epithelial (HBE) cells treated with cigarette smoke extract (CSE). Finally, we established that, in HBE cells, andrographolide reversed the CSE-induced EMT via decreasing IL-6 levels and, in an animal model, prevented CS-induced lung inflammation and small airway remodeling, indicating that it has potential clinical application for CS-induced pulmonary dysfunction and COPD.

Integration of microbiology, molecular pathology, and epidemiology: a new paradigm to explore the pathogenesis of microbiome-driven neoplasms

Molecular pathological epidemiology (MPE) is an integrative transdisciplinary field that addresses heterogeneous effects of exogenous and endogenous factors (collectively termed 'exposures'), including microorganisms, on disease occurrence and consequences, utilising molecular pathological signatures of the disease. In parallel with the paradigm of precision medicine, findings from MPE research can provide aetiological insights into tailored strategies of disease prevention and treatment. Due to the availability of molecular pathological tests on tumours, the MPE approach has been utilised predominantly in research on cancers including breast, lung, prostate, and colorectal carcinomas. Mounting evidence indicates that the microbiome (inclusive of viruses, bacteria, fungi, and parasites) plays an important role in a variety of human diseases including neoplasms. An alteration of the microbiome may be not only a cause of neoplasia but also an informative biomarker that indicates or mediates the association of an epidemiological exposure with health conditions and outcomes. To adequately educate and train investigators in this emerging area, we herein propose the integration of microbiology into the MPE model (termed 'microbiology-MPE'), which could improve our understanding of the complex interactions of environment, tumour cells, the immune system, and microbes in the tumour microenvironment during the carcinogenic process. Using this approach, we can examine how lifestyle factors, dietary patterns, medications, environmental exposures, and germline genetics influence cancer development and progression through impacting the microbial communities in the human body. Further integration of other disciplines (e.g. pharmacology, immunology, nutrition) into microbiology-MPE would expand this developing research frontier. With the advent of high-throughput next-generation sequencing technologies, researchers now have increasing access to large-scale metagenomics as well as other omics data (e.g. genomics, epigenomics, proteomics, and metabolomics) in population-based research. The integrative field of microbiology-MPE will open new opportunities for personalised medicine and public health. Copyright © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.