Circulating Sex Hormones Are Associated With Gastric and Colorectal Cancers but Not Esophageal Adenocarcinoma in the UK Biobank

Use of 5-alpha reductase inhibitors and risk of gastrointestinal cancers in men with benign prostatic hyperplasia: A population-based cohort study

Pre-clinical evidence suggests that 5-alpha reductase inhibitors (5ARi's), prescribed in the treatment of benign prostatic hyperplasia, reduce colorectal and gastro-oesophageal cancer incidence via action on the male hormonal pathway. However, few studies to date have investigated this association at the population level. Our study aimed to investigate the risk of colorectal and gastro-oesophageal cancers with the use of 5ARi's. We conducted a retrospective cohort study of new users of 5ARi's and alpha-blockers among patients with benign prostatic hyperplasia in the UK Clinical Practice Research Datalink. Patients were followed until a first ever diagnosis of colorectal or gastro-oesophageal cancer, death from any cause or end of registration with the general practice or 31st of December 2017. Cox proportional hazards models with inverse probability of treatment weights were used to calculate weighted hazard ratios (HR) and 95% confidence intervals (CIs) of incident colorectal cancer or gastro-oesophageal cancer associated with the use of 5ARi's compared to alpha-blockers. During a mean follow-up of 6.6 years, we found no association between the use of 5ARi's and colorectal (HR: 1.13, 95% CI 0.91-1.41) or gastro-oesophageal (HR 1.14, 95% CI 0.76-1.63) cancer risk compared to alpha-blockers. Sensitivity analysis showed largely consistent results when varying lag periods, using multiple imputations, and accounting for competing risk of death. Our study found no association between the use of 5ARi's and risk of colorectal or gastro-oesophageal cancer in men with benign prostatic hyperplasia.

Sex hormones and risk of lung and colorectal cancers in women: a Mendelian randomization study

The roles of sex hormones such as estradiol, testosterone, and sex hormone-binding globulin (SHBG) in the etiology of lung and colorectal cancers in women, among the most common cancers after breast cancer, are unclear. This Mendelian randomization (MR) study evaluated such potential causal associations in women of European ancestry. We used summary statistics data from genome-wide association studies (GWASs) on sex hormones and from the Trøndelag Health (HUNT) Study and large consortia on cancers. There was suggestive evidence of genetically predicted 1-standard deviation increase in total testosterone levels being associated with a lower risk of lung non-adenocarcinoma (hazard ratio (HR) 0.60, 95% CI 0.37-0.98) in the HUNT Study. However, this was not confirmed by using data from a larger consortium. In general, we did not find convincing evidence to support a causal role of sex hormones on risk of lung and colorectal cancers in women of European ancestry.

Reproductive factors, hormonal interventions, and gastric cancer risk in the Stomach cancer Pooling (StoP) Project

BACKGROUND

Gastric cancer incidence is higher in men, and a protective hormone-related effect in women is postulated. We aimed to investigate and quantify the relationship in the Stomach cancer Pooling (StoP) Project consortium.

METHODS

A total of 2,084 cases and 7,102 controls from 11 studies in seven countries were included. Summary odds ratios (ORs) and 95% confidence intervals (CIs) assessing associations of key reproductive factors and menopausal hormone therapy (MHT) with gastric cancer were estimated by pooling study-specific ORs using random-effects meta-analysis.

RESULTS

A duration of fertility of ≥ 40 years (vs. < 20), was associated with a 25% lower risk of gastric cancer (OR = 0.75; 95% CI: 0.58-0.96). Compared with never use, ever, 5-9 years and ≥ 10 years use of MHT in postmenopausal women, showed ORs of 0.73 (95% CI: 0.58-0.92), 0.53 (95% CI: 0.34-0.84) and 0.71 (95% CI: 0.50-1.00), respectively. The associations were generally similar for anatomical and histologic subtypes.

CONCLUSION

Our results support the hypothesis that reproductive factors and MHT use may lower the risk of gastric cancer in women, regardless of anatomical or histologic subtypes. Given the variation in hormones over the lifespan, studies should address their effects in premenopausal and postmenopausal women. Furthermore, mechanistic studies may inform potential biological processes.

Sex differences in colorectal cancer: with a focus on sex hormone-gut microbiome axis

Sexual dimorphism has been observed in the incidence and prognosis of colorectal cancer (CRC), with men generally exhibiting a slightly higher incidence than women. Research suggests that this difference may be attributed to variations in sex steroid hormone levels and the gut microbiome. The gut microbiome in CRC shows variations in composition and function between the sexes, leading to the concept of 'microgenderome' and 'sex hormone-gut microbiome axis.' Conventional research indicates that estrogens, by promoting a more favorable gut microbiota, may reduce the risk of CRC. Conversely, androgens may have a direct pro-tumorigenic effect by increasing the proportion of opportunistic pathogens. The gut microbiota may also influence sex hormone levels by expressing specific enzymes or directly affecting gonadal function. However, this area remains controversial. This review aims to explore the differences in sex hormone in CRC incidence, the phenomenon of sexual dimorphism within the gut microbiome, and the intricate interplay of the sex hormone-gut microbiome axis in CRC. The objective is to gain a better understanding of these interactions and their potential clinical implications, as well as to introduce innovative approaches to CRC treatment.

Identification of phenomic data in the pathogenesis of cancers of the gastrointestinal (GI) tract in the UK biobank

Gastrointestinal (GI) cancers account for a significant incidence and mortality rates of cancers globally. Utilization of a phenomic data approach allows researchers to reveal the mechanisms and molecular pathogenesis of these conditions. We aimed to investigate the association between the phenomic features and GI cancers in a large cohort study. We included 502,369 subjects aged 37-73 years in the UK Biobank recruited since 2006, followed until the date of the first cancer diagnosis, date of death, or the end of follow-up on December 31st, 2016, whichever occurred first. Socio-demographic factors, blood chemistry, anthropometric measurements and lifestyle factors of participants collected at baseline assessment were analysed. Unvariable and multivariable logistic regression were conducted to determine the significant risk factors for the outcomes of interest, based on the odds ratio (OR) and 95% confidence intervals (CI). The analysis included a total of 441,141 participants, of which 7952 (1.8%) were incident GI cancer cases and 433,189 were healthy controls. A marker, cystatin C was associated with total and each gastrointestinal cancer (adjusted OR 2.43; 95% CI 2.23-2.64). In this cohort, compared to Asians, the Whites appeared to have a higher risk of developing gastrointestinal cancers. Several other factors were associated with distinct GI cancers. Cystatin C and race appear to be important features in GI cancers, suggesting some overlap in the molecular pathogenesis of GI cancers. Given the small proportion of Asians within the UK Biobank, the association between race and GI cancers requires further confirmation.

Genetic variants in primary cilia-related genes associated with the prognosis of first-line chemotherapy in colorectal cancer

BACKGROUND

Primary cilia are antenna-like organelles that conduct physical and chemical signals, which affect cell proliferation, migration, and differentiation. Some researchers have reported the correlation between primary cilia-related genes and prognosis of colorectal cancer (CRC).

METHODS

The association between single nucleotide polymorphisms (SNPs) of primary cilia-related genes and outcome after the first-line chemotherapy was explored by the Cox regression model. Expression qualitative trait locus (eQTL) analysis was performed to explore the impact of SNPs on gene expression. Tumor Immune Estimation Resource and TISIDB databases were used for investigating the relevance between ODF2L and tumor infiltration immune cells and immunomodulators.

RESULTS

We identified that rs4288473 C allele of ODF2L had poor progression-free survival (PFS) and overall survival (OS) of CRC patients in the additive model (adjusted HRPFS  = 1.39, 95% CI = 1.14-1.70, p = 1.36 × 10-3 , and adjusted HROS  = 1.31, 95% CI = 1.03-1.65, p = 2.62 × 10-2 ). The stratified analysis indicated that rs4288573 CC/CT genotype was involved with poor prognosis in the irinotecan-treated subgroup (PPFS  = 1.03 × 10-2 , POS  = 3.29 × 10-3 ). Besides, ODF2L mRNA expression level was notably up-regrated in CRC tissues. The C allele of rs4288573 was notably related to higher ODF2L mRNA expression levels based on eQTL analysis. Functionally, knockdown of ODF2L inhibited cell proliferation and decrease the chemoresistance of HCT-116 and DLD-1 cells to irinotecan.

CONCLUSION

Our study indicates that rs4288573 in ODF2L is a potential predictor of the chemotherapy prognosis of CRC.

Identification of plasma proteomic signatures associated with the progression of cardia gastric cancer and precancerous lesions

Objective

Considering that there are no effective biomarkers for the screening of cardia gastric cancer (CGC), we developed a noninvasive diagnostic approach, employing data-independent acquisition (DIA) proteomics to identify candidate protein markers.

Methods

Plasma samples were obtained from 40 subjects, 10 each for CGC, cardia high-grade dysplasia (CHGD), cardia low-grade dysplasia (CLGD), and healthy controls. Proteomic profiles were obtained through liquid chromatography-mass spectrometry (LC-MS/MS-based DIA proteomics. Candidate plasma proteins were identified by weighted gene co-expression network analysis (WGCNA) combined with machine learning and further validated by the Human Protein Atlas (HPA) database. The area under the receiver operating characteristic curve (AUC) was used to evaluate the performance of the biomarker panel.

Results

There was a clear distinction in proteomic features among CGC, CHGD, CLGD, and the healthy controls. According to the WGCNA, we found 42 positively associated and 164 inversely associated proteins related to CGC progression and demonstrated several canonical cancer-associated pathways. Combined with the results from random forests, LASSO regression, and immunohistochemical results from the HPA database, we identified three candidate proteins (GSTP1, CSRP1, and LY6G6F) that could together distinguish CLGD (AUC = 0.91), CHGD (AUC = 0.99) and CGC (AUC = 0.98) from healthy controls with excellent accuracy.

Conclusions

The panel of protein biomarkers showed promising diagnostic potential for CGC and precancerous lesions. Further validation and a larger-scale study are warranted to assess its potential clinical applications, suggesting a potential avenue for CGC prevention in the future.

Circulating hormones and risk of gastric cancer by subsite in three cohort studies

BACKGROUND

Obesity has been positively associated with gastric cancer. Excess fat impacts hormones, which have been implicated in carcinogenesis. We investigated obesity-related hormones and cardia gastric cancer (CGC) and non-cardia gastric cancer (NCGC) risk.

METHODS

Nested case-control studies were conducted within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort (61 CGCs, and 172 NCGCs and matched controls) and the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) study (100 CGCs and 65 NCGCs and matched controls); serum hormones were measured. In UK-Biobank (n = 458,713), we included 137 CGCs and 92 NCGCs. Sex-specific analyses were conducted. For EPIC and ATBC, odds ratios (ORs), and for UK-Biobank hazard ratios (HRs), were estimated using conditional logistic regression and Cox regression, respectively.

RESULTS

Insulin-like growth-factor-1 was positively associated with CGC and NCGC in EPIC men (ORper 1-SD increase 1.94, 95% CI 1.03-3.63; ORper 1-SD increase 1.63, 95% CI 1.05-2.53, respectively), with similar findings for CGC in UK-Biobank women (HRper 1-SD increase 1.76, 95% CI 1.08-2.88). Leptin in EPIC men and C-peptide in EPIC women were positively associated with NCGC (ORT3 vs. T1 2.72, 95% CI 1.01-7.34 and ORper 1-SD increase 2.17, 95% CI 1.19-3.97, respectively). Sex hormone-binding globulin was positively associated with CGC in UK-Biobank men (HRper 1-SD increase 1.29, 95% CI 1.02-1.64). Conversely, ghrelin was inversely associated with NCGC among EPIC and ATBC men (ORper 1-SD increase 0.53, 95% CI 0.34-0.84; ORper 1-SD increase 0.22, 95% CI 0.10-0.50, respectively). In addition, dehydroepiandrosterone was inversely associated with CGC in EPIC and ATBC men combined.

CONCLUSIONS

Some obesity-related hormones influence CGC and NCGC risk.

Sex-specific disparities of serum pepsinogen I in relation to body mass index

OBJECTIVES

The clinical significance of serum pepsinogen (PG) for screening gastric cancer has been a controversial topic. Serum PG I levels have been demonstrated to be correlated with age, sex, and the Helicobacter pylori (HP) infection. However, the underlying factors that influence serum PG I variations remain to be fully elucidated. We aimed to evaluate the impacts of sex and body mass index (BMI) on PG I in Chinese population.

METHODS

The cross-sectional study recruited 4,299 apparently healthy participants in Fujian Province. Serum PG levels were automatically measured using ELISA method. Serum H. pylori-IgG antibody was detected by the colloidal gold immunoassay. Clinical characteristics were obtained by questionnaire.

RESULTS

Totally, 2,263 participants who had tests of serum PG and anti-HP IgG antibody were enrolled. Increased BMI and serum uric acid were observed in males with low PG I value (<70 μg/L). Multiple logistic regression showed the presence of overweight was the independent risk factor for male participants with low PG I level (odds ratio [OR] 1.519; p=0.017). However, the association was not found in females.

CONCLUSIONS

Sex-specific association of serum low PG I with overweight was observed in the southeast coastal areas of China. Thus, effects of sexual dimorphism should not be ignored during the clinical utilization of serum PG I.

Genetic causal relationship between age at menarche and benign oesophageal neoplasia identified by a Mendelian randomization study

OBJECTIVE

The occurrence and development of oesophageal neoplasia (ON) is closely related to hormone changes. The aim of this study was to investigate the causal relationships between age at menarche (AAMA) or age at menopause (AAMO) and benign oesophageal neoplasia (BON) or malignant oesophageal neoplasia (MON) from a genetic perspective.

METHODS

Genome-wide association study (GWAS) summary data of exposures (AAMA and AAMO) and outcomes (BON and MON) were obtained from the IEU OpenGWAS database. We performed a two-sample Mendelian randomization (MR) study between them. The inverse variance weighted (IVW) was used as the main analysis method, while the MR Egger, weighted median, simple mode, and weighted mode were supplementary methods. The maximum likelihood, penalized weighted median, and IVW (fixed effects) were validation methods. We used Cochran's Q statistic and Rucker's Q statistic to detect heterogeneity. The intercept test of the MR Egger and global test of MR pleiotropy residual sum and outlier (MR-PRESSO) were used to detect horizontal pleiotropy, and the distortion test of the MR-PRESSO analysis was used to detect outliers. The leave-one-out analysis was used to detect whether the MR analysis was affected by single nucleotide polymorphisms (SNPs). In addition, the MR robust adjusted profile score (MR-RAPS) method was used to assess the robustness of MR analysis.

RESULTS

The random-effects IVW results showed that AAMA had a negative genetic causal relationship with BON (odds ratio [OR] = 0.285 [95% confidence interval [CI]: 0.130-0.623], P = 0.002). The weighted median, maximum likelihood, penalized weighted median, and IVW (fixed effects) were consistent with random-effects IVW (P < 0.05). The MR Egger, simple mode and weighted mode results showed that AAMA had no genetic causal relationship with BON (P > 0.05). However, there were no causal genetic relationships between AAMA and MON (OR = 1.132 [95%CI: 0.621-2.063], P = 0.685), AAMO and BON (OR = 0.989 [95%CI: 0.755-1.296], P = 0.935), or AAMO and MON (OR = 1.129 [95%CI: 0.938-1.359], P = 0.200). The MR Egger, weighted median, simple mode, weighted mode, maximum likelihood, penalized weighted median, and IVW (fixed effects) were consistent with a random-effects IVW (P > 0.05). MR analysis results showed no heterogeneity, the horizontal pleiotropy and outliers (P > 0.05). They were not driven by a single SNP, and were normally distributed (P > 0.05).

CONCLUSION

Only AAMA has a negative genetic causal relationship with BON, and no genetic causal relationships exist between AAMA and MON, AAMO and BON, or AAMO and MON. However, it cannot be ruled out that they are related at other levels besides genetics.

Testosterone therapy and cancer risks among men in the SEER-Medicare linked database

BACKGROUND

We examined associations between two forms of testosterone therapy (TT) and risks of seven cancers among men.

METHODS

SEER-Medicare combines cancer registry data from the Surveillance, Epidemiology, and End Results programme with Medicare claims. Our population-based case-control study included incident cancer cases diagnosed between 1992-2015: prostate (n = 130,713), lung (n = 105,466), colorectal (n = 56,433), bladder (n = 38,873), non-Hodgkin lymphoma (n = 17,854), melanoma (n = 14,241), and oesophageal (n = 9116). We selected 100,000 controls from a 5% random sample of Medicare beneficiaries and used logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

TT was associated with lower risk of distant-stage prostate cancer (injection/implantation OR = 0.72, 95% CI: 0.60-0.86; topical OR = 0.50, 95% CI: 0.24-1.03). We also observed inverse associations for distant-stage colorectal cancer (injection/implantation OR = 0.75, 95% CI: 0.62-0.90; topical OR = 0.11, 95% CI: 0.05-0.24). Risks of distant-stage colorectal and prostate cancers decreased with time after initiating TT by injection/implantation. By contrast, TT was positively associated with distant-stage melanoma (injection/implantation OR = 1.70, 95% CI: 1.37-2.11). TT was not associated with bladder cancer, oesophageal cancer, lung cancer or non-Hodgkin lymphoma.

CONCLUSION

TT was inversely associated with distant-stage prostate and colorectal cancers but was positively associated with distant-stage melanoma. These observations may suggest an aetiologic role for TT or the presence of residual confounding.

Sociodemographic disparities in gastric cancer and the gastric precancerous cascade: A population-based study

BACKGROUND

Gastric carcinogenesis is a multistep process initiating with chronic gastritis and progressing through atrophy, intestinal metaplasia, and dysplasia to carcinoma. This study aims to comprehensively investigate sociodemographic disparities in each stage of gastric carcinogenesis and estimate to what extent the inequalities could be ascribed to risk factors of gastric cancer (GC).

METHODS

We used the baseline data from a community-based study in China's high-risk areas, totalling 27094 participants. Gastric mucosa status was ascertained by endoscopy and biopsies. An overall socioeconomic status (SES) variable was generated by latent class analysis. We calculated relative risks (RRs) and 95% confidence intervals (CIs) using modified Poisson regression to assess associations of sociodemographic factors with each cascade stage. We estimated the percentage of the excess risk for neoplastic lesions among vulnerable populations that can be explained by established risk factors.

RESULTS

Age and sex showed associations with all gastric lesions, whose RRs increased with lesion progressing. Compared with individuals without schooling, the RRs of neoplastic lesions for people with primary, secondary, and post-secondary education were 0·86 (95% CI 0·76-0·97), 1·00 (95% CI 0·88-1·13), and 0·70 (95% CI 0·47-1·03), respectively. Participants with medium SES had a lower risk of neoplastic lesions than people in the low SES group (RR 0·83, 95% CI 0·74-0·93). GC risk factors could explain 33·6% of the excess risk of neoplastic lesions among men and a small proportion of the disparities among SES groups.

INTERPRETATION

Age and sex were essential sociodemographic factors for GC and precursor diseases. Individuals with low educational levels or SES were more likely to have neoplastic lesions. About one-third of the sex difference and a slight fraction of the socioeconomic inequalities could be attributed to included risk factors.

FUNDING

Sanming Project of Medicine in Shenzhen, National Natural Science Foundation, and Special Project of Bejing-Tianjin-Hebei Basic Research Cooperation.

Circulating Sex Hormone Levels and Colon Cancer Risk in Men: A Nested Case-Control Study and Meta-Analysis

BACKGROUND

Endogenous sex hormones may contribute to higher colorectal cancer incidence rates in men compared with women, but despite an increased number of studies, clear evidence is lacking.

METHODS

We conducted a comprehensive nested case-control study of circulating concentrations of sex hormones, sex hormone precursors, and sex hormone binding globulin (SHBG) in relation to subsequent colon cancer risk in European men. Concentrations were measured using liquid LC/MS-MS in prospectively collected plasma samples from 690 cases and 690 matched controls from the European Prospective Investigation into Cancer and Nutrition (EPIC) and the Northern Sweden Health and Disease Study (NSHDS) cohorts. Multivariable conditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI). In addition, we conducted a meta-analysis of previous studies on men.

RESULTS

Circulating levels of testosterone (OR, 0.68; 95% CI, 0.51-0.89) and SHBG (OR, 0.77; 95% CI, 0.62-0.96) were inversely associated with colon cancer risk. For free testosterone, there was a nonsignificant inverse association (OR, 0.83; 95% CI, 0.58-1.18). In a dose-response meta-analysis of endogenous sex hormone levels, inverse associations with colorectal/colon cancer risk were found for testosterone [relative risks (RR) per 100 ng/dL = 0.98; 95% CI, 0.96-1.00; I2 = 22%] and free testosterone (RR per 1 ng/dL = 0.98; 95% CI, 0.95-1.00; I2 = 0%).

CONCLUSIONS

Our results provide suggestive evidence for the association between testosterone, SHBG, and male colon cancer development.

IMPACT

Additional support for the involvement of sex hormones in male colon cancer.

Menopausal hormone therapy and risk of oesophageal adenocarcinoma in a population-based cohort study

BACKGROUND

Oesophageal adenocarcinoma is characterised by a strong male predominance. We aimed to test the hypothesis that menopausal hormonal therapy decreases the risk of oesophageal adenocarcinoma.

METHODS

This population-based cohort study included all women who used systemic menopausal hormonal therapy (exposed) in Sweden between 2005 and 2018. For each exposed participant, five randomly selected female age-matched non-users of menopausal hormonal therapy (unexposed) were included. Cox regression provided hazard ratios (HR) with 95% confidence intervals (CI) adjusted for age, smoking-related diagnoses, Helicobacter pylori eradication, use of non-steroidal anti-inflammatory drugs/aspirin, use of statins and hysterectomy.

RESULTS

The study included 296,964 users of menopausal hormonal therapy and 1,484,820 non-users. Ever-users of menopausal hormonal therapy had an overall decreased risk of oesophageal adenocarcinoma (HR 0.78, 95% CI 0.63-0.97), which remained unchanged after further adjustment for gastro-oesophageal reflux disease (HR 0.78, 95% CI 0.63-0.97) and obesity/diabetes (HR 0.79, 95% CI 0.63-0.98). Decreased HRs were indicated both in users of oestrogen only (HR 0.82, 95% CI 0.60-1.12) and oestrogen combined with progestogen (HR 0.75, 95% CI 0.56-1.00). The risk reduction was more pronounced in users younger than 60 years (HR 0.57, 95% CI 0.38-0.86).

CONCLUSIONS

Menopausal hormone therapy in women may decrease the risk of oesophageal adenocarcinoma.

Circulating Levels of Testosterone, Sex Hormone Binding Globulin and Colorectal Cancer Risk: Observational and Mendelian Randomization Analyses

BACKGROUND

Epidemiologic studies evaluating associations between sex steroid hormones and colorectal cancer risk have yielded inconsistent results. To elucidate the role of circulating levels of testosterone, and sex hormone-binding globulin (SHBG) in colorectal cancer risk, we conducted observational and Mendelian randomization (MR) analyses.

METHODS

The observational analyses included 333,530 participants enrolled in the UK Biobank with testosterone and SHBG measured. HRs and 95% confidence intervals (CI) were estimated using multivariable Cox proportional hazards models. For MR analyses, genetic variants robustly associated with hormone levels were identified and their association with colorectal cancer (42,866 cases/42,752 controls) was examined using two-sample MR.

RESULTS

In the observational analysis, there was little evidence that circulating levels of total testosterone were associated with colorectal cancer risk; the MR analyses showed a greater risk for women (OR per 1-SD = 1.09; 95% CI, 1.01-1.17), although pleiotropy may have biased this result. Higher SHBG concentrations were associated with greater colorectal cancer risk for women (HR per 1-SD = 1.16; 95% CI, 1.05-1.29), but was unsupported by the MR analysis. There was little evidence of associations between free testosterone and colorectal cancer in observational and MR analyses.

CONCLUSIONS

Circulating concentrations of sex hormones are unlikely to be causally associated with colorectal cancer. Additional experimental studies are required to better understand the possible role of androgens in colorectal cancer development.

IMPACT

Our results from large-scale analyses provide little evidence for sex hormone pathways playing a causal role in colorectal cancer development.See related commentary by Hang and Shen, p. 1302.

Sex Hormone and Colorectal Cancer: The Knowns and Unknowns

Sex hormones have been suggested as a contributor to gender disparity in incidence and mortality of colorectal cancer, but previous observational studies on endogenous sex hormones and colorectal cancer risk have led to contradictory results. Leveraging the large-scale UK biobank resource, Dimou and colleagues performed both observational and Mendelian randomization (MR) analyses to investigate the association of serum testosterone and sex hormone binding globulin concentrations with the risk of colorectal cancer. Although the findings provide little evidence for independent roles of the hormones in colorectal cancer, further interrogation of possible mediating effects of sex hormones on the causal pathways of colorectal cancer could deepen our understanding of colorectal cancer etiology and improve tailored prevention. While MR analysis is useful for inferring causality in observational studies, the current null results should be interpreted with caution because of insufficient statistical power and predefined assumptions of linearity. Moreover, given the widespread use of testosterone supplementation in older men to restore age-related decline of endogenous concentrations, large and long-term randomized controlled trials are required to clarify the effect of testosterone on colorectal cancer risk, which would provide critical evidence for health decision making.See related article by Dimou et al., p. 1336.

Risk prediction models for colorectal cancer: Evaluating the discrimination due to added biomarkers

Most risk prediction models for colorectal cancer (CRC) are based on questionnaires and show a modest discriminatory ability. Therefore, we aim to develop risk prediction models incorporating plasma biomarkers for CRC to improve discrimination. We assessed the predictivity of 11 biomarkers in 736 men in the Health Professionals Follow-up Study and 639 women in the Nurses' Health Study. We used stepwise logistic regression to examine whether a set of biomarkers improved the predictivity on the basis of predictors in the National Cancer Institute's (NCI) Colorectal Cancer Risk Assessment Tool. Model discrimination was assessed using C-statistics. Bootstrap with 500 randomly sampled replicates was used for internal validation. The models containing each biomarker generated a C-statistic ranging from 0.50 to 0.59 in men and 0.50 to 0.54 in women. The NCI model demonstrated a C-statistic (95% CI) of 0.67 (0.62-0.71) in men and 0.58 (0.54-0.63) in women. Through stepwise selection of biomarkers, the C-statistic increased to 0.70 (0.66-0.74) in men after adding growth/differentiation factor 15, total adiponectin, sex hormone binding globulin and tumor necrosis factor receptor superfamily member 1B (P for difference = 0.008); and increased to 0.62 (0.57-0.66) in women after further including insulin-like growth factor 1 and insulin-like growth factor-binding protein 3 (P for difference = .06). The NCI + selected biomarkers model was internally validated with a C-statistic (95% CI) of 0.73 (0.70-0.77) in men and 0.66 (0.61-0.70) in women. Circulating plasma biomarkers may improve the performance of risk factor-based prediction model for CRC.

Visceral Obesity, Metabolic Syndrome, and Esophageal Adenocarcinoma

Esophageal adenocarcinoma (EAC) represents an exemplar of obesity-associated carcinogenesis, with a progressive increase in EAC risk with increased body mass index. In this context, there is increased focus on visceral adipose tissue and associated metabolic dysfunction, including hypertension, diabetes mellitus and hyperlipidemia, or combinations of these in the metabolic syndrome. Visceral obesity (VO) may promote EAC via both directly impacting on gastro-esophageal reflux disease and Barrett's esophagus, as well as via reflux-independent effects, involving adipokines, growth factors, insulin resistance, and the microbiome. In this review these pathways are explored, including the impact of VO on the tumor microenvironment, and on cancer outcomes. The current evidence-based literature regarding the role of dietary, lifestyle, pharmacologic and surgical interventions to modulate the risk of EAC is explored.