Clinical significance of combined tumour-infiltrating lymphocytes and microsatellite instability status in colorectal cancer: a systematic review and network meta-analysis.

BACKGROUND: Microsatellite instability (MSI) status and tumour-infiltrating lymphocytes (TIL) are established prognostic factors in colorectal cancer. Previous studies evaluating the combination of TIL and MSI status identified distinct colorectal cancer subtypes with unique prognostic associations. However, these studies were often limited by sample size, particularly for MSI-high (MSI-H) tumours, and there is no comprehensive summary of the available evidence. We aimed to review the literature to compare the survival outcomes associated with the subtypes derived from the integrated MSI-TIL classification in patients with colorectal cancer. METHODS: In this systematic review and network meta-analysis, we searched PubMed, Embase, Scopus, and the Cochrane Library without language restrictions, for articles published between Jan 1, 1990, and March 13, 2024. Patient cohorts comparing different combinations of TIL (high or low) and MSI status (MSI or microsatellite stable [MSS]) in patients with surgically resected colorectal cancer were included. Studies were excluded if they focused on neoadjuvant therapy or on other immune markers such as B cells or macrophages. Methodological quality assessment was done with the Newcastle-Ottawa scale; data appraisal and extraction was done independently by two reviewers. Summary estimates were extracted from published reports. The primary outcomes were overall survival, disease-free survival, and cancer-specific survival. A frequentist network meta-analysis was done to compare hazard ratios (HRs) and 95% CI for each outcome. The MSI-TIL subgroups were prognostically ranked based on P-score, bias, magnitude, and precision of associations with each outcome. The protocol is registered with PROSPERO (CRD42023461108). FINDINGS: Of 302 studies initially identified, 21 studies (comprising 14 028 patients) were included in the systematic review and 19 (13 029 patients) in the meta-analysis. Nine studies were identified with a low risk of bias and the remaining ten had a moderate risk of bias. The MSI-TIL-high (MSI-TIL-H) subtype exhibited longer overall survival (HR 0·45, 95% CI 0·34-0·61; I2=77·7%), disease-free survival (0·43, 0·32-0·58; I2=61·6%), and cancer-specific survival (0·53, 0·43-0·66; I2=0%), followed by the MSS-TIL-H subtype for overall survival (HR 0·53, 0·41-0·69; I2=77·7%), disease-free survival (0·52, 0·41-0·64; I2=61·6%), and cancer-specific survival (0·55, 0·47-0·64; I2=0%) than did patients with MSS-TIL-low tumours (MSS-TIL-L). Patients with the MSI-TIL-L subtype had similar overall survival (0·88, 0·66-1·18; I2=77·7%) and disease-free survival (0·93, 0·69-1·26; I2=61·6%), but a modestly longer cancer-specific survival (0·72, 0·57-0·90; I2=0%) than did the MSS-TIL-L subtype. Results from the direct and indirect evidence were strongly congruous. INTERPRETATION: The findings from this network meta-analysis suggest that better survival was only observed among patients with TIL-H colorectal cancer, regardless of MSI or MSS status. The integrated MSI-TIL classification should be further explored as a predictive tool for clinical decision-making in early-stage colorectal cancer. FUNDING: German Research Council (HO 5117/2-2).

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.

Excess weight, polygenic risk score and findings of colorectal neoplasms at screening colonoscopy.

INTRODUCTION: Excess weight is an established risk factor for colorectal cancer (CRC). However, evidence is lacking on how its impact varies by polygenic risk at different stages of colorectal carcinogenesis. METHODS: We assessed the individual and joint associations of body mass index (BMI) and polygenic risk scores (PRSs) with findings of colorectal neoplasms among 4,784 participants of screening colonoscopy. Adjusted odds ratios (aORs) for excess weight derived by multiple logistic regression were converted to genetic risk equivalents (GREs) to quantify the impact of excess weight compared to genetic predisposition. RESULTS: Overweight and obesity (BMI 25-<30 and ≥30 kg/m2) were associated with increased risk of any colorectal neoplasm (aOR [95% CI] 1.26 [1.09-1.45] and 1.47 [1.24-1.75]). Obesity was associated with increased risk of advanced colorectal neoplasm (aOR [95% CI] 1.46 [1.16-1.84]). Dose-response relationships were seen for the PRS (stronger for advanced neoplasms than any neoplasms), with no interaction with BMI, suggesting multiplicative effects of both factors. Obese participants with a PRS in the highest tertile had a 2.3-fold (95% CI 1.7-3.1) and 2.9-fold (95%CI 1.9-4.3) increased risk of any colorectal neoplasm and advanced colorectal neoplasm, respectively. The aOR of obesity translated into a GRE of 38, meaning that its impact was estimated to be equivalent to the risk caused by 38 percentiles higher PRS for colorectal neoplasm. CONCLUSION: Excess weight and polygenic risk are associated with increased risk of colorectal neoplasms in a multiplicative manner. Maintaining normal weight is estimated to have an equivalent effect as having 38 percentiles lower PRS.

Longer Interval Between First Colonoscopy With Negative Findings for Colorectal Cancer and Repeat Colonoscopy.

Importance: For individuals without a family history of colorectal cancer (CRC), colonoscopy screening every 10 years is recommended to reduce CRC incidence and mortality. However, debate exists about whether and for how long this 10-year interval could be safely expanded. Objective: To assess how many years after a first colonoscopy with findings negative for CRC a second colonoscopy can be performed. Design, Setting, and Participants: This cohort study leveraged Swedish nationwide register-based data to examine CRC diagnoses and CRC-specific mortality among individuals without a family history of CRC. The exposed group included individuals who had a first colonoscopy with findings negative for CRC at age 45 to 69 years between 1990 and 2016. The control group included individuals matched by sex, birth year, and baseline age (ie, the age of their matched exposed individual when the exposed individual's first colonoscopy with findings negative for CRC was performed). Individuals in the control group either did not have a colonoscopy during the follow-up or underwent colonoscopy that resulted in a CRC diagnosis. Up to 18 controls were matched with each exposed individual. Individuals were followed up from 1990 to 2018, and data were analyzed from November 2022 to November 2023. Exposure: A first colonoscopy with findings negative for CRC, defined as a first colonoscopy without a diagnosis of colorectal polyp, adenoma, carcinoma in situ, or CRC before or within 6 months after screening. Main Outcomes and Measures: The primary outcomes were CRC diagnosis and CRC-specific death. The 10-year standardized incidence ratio and standardized mortality ratio were calculated to compare risks of CRC and CRC-specific death in the exposed and control groups based on different follow-up screening intervals. Results: The sample included 110 074 individuals (65 147 females [59.2%]) in the exposed group and 1 981 332 (1 172 646 females [59.2%]) in the control group. The median (IQR) age for individuals in both groups was 59 (52-64) years. During up to 29 years of follow-up of individuals with a first colonoscopy with findings negative for CRC, 484 incident CRCs and 112 CRC-specific deaths occurred. After a first colonoscopy with findings negative for CRC, the risks of CRC and CRC-specific death in the exposed group were significantly lower than those in their matched controls for 15 years. At 15 years after a first colonoscopy with findings negative for CRC, the 10-year standardized incidence ratio was 0.72 (95% CI, 0.54-0.94) and the 10-year standardized mortality ratio was 0.55 (95% CI, 0.29-0.94). In other words, the 10-year cumulative risk of CRC in year 15 in the exposed group was 72% that of the 10-year cumulative risk of CRC in the control group. Extending the colonoscopy screening interval from 10 to 15 years in individuals with a first colonoscopy with findings negative for CRC could miss the early detection of only 2 CRC cases and the prevention of 1 CRC-specific death per 1000 individuals, while potentially avoiding 1000 colonoscopies. Conclusions and Relevance: This cohort study found that for the population without a family history of CRC, the 10-year interval between colonoscopy screenings for individuals with a first colonoscopy with findings negative for CRC could potentially be extended to 15 years. A longer interval between colonoscopy screenings could be beneficial in avoiding unnecessary invasive examinations.

Utilization of colorectal cancer screening tests across European countries: a cross-sectional analysis of the European health interview survey 2018-2020.

Background: Colorectal cancer (CRC) screening has been shown to reduce CRC incidence and mortality, and most European countries have started to implement CRC screening programs in the past 20 years. Consequently, this study aimed to estimate the utilization of fecal tests and colonoscopy, as well as investigate factors associated with their utilization based on specific screening program characteristics in European countries. Methods: We analyzed data from the European Health Interview Survey 2018-2020 to determine the utilization of fecal tests [guaiac-based fecal occult blood test (gFOBT) or fecal immunochemical test (FIT)] within the preceding 2 years or colonoscopy within the preceding 10 years among people aged 50-74 years, based on the type of screening offered in each country. Using multivariable logistic regression and sub-group meta-analysis, factors associated with screening use were determined. Findings: The analyses included data from 129,750 respondents across 29 European countries, with participant counts ranging from 1511 individuals in Iceland to 11,755 individuals in Germany. Unit response rates ranged from 22% to 88%. The use of either test was highest among countries with fully rolled-out programs with fecal tests [from 37.7% (867/2379) in Croatia to 74.9% (2321/3085) in Denmark] and in countries offering colonoscopy as an alternative screening method [from 26.2% (854/3329) in Greece to 75.4% (1192/1760) in Luxembourg]. We observed the lowest utilization of either test in countries with no program or small-scale programs [6.3% (195/3179) in Bulgaria to 34.2% (722/2144) in Latvia]. Across all types of screening offers, younger age, being without a partner, low education, rural residence, and living in large households were associated with lower utilization, as were poor lifestyle scores and prolonged periods without physician consultation. Interpretation: Our findings point to large disparities and much room for improvement in CRC screening offers and utilization across Europe. Funding: There was no funding source for this study.

Genome-wide interaction study of dietary intake of fibre, fruits, and vegetables with risk of colorectal cancer.

BACKGROUND: Consumption of fibre, fruits and vegetables have been linked with lower colorectal cancer (CRC) risk. A genome-wide gene-environment (G × E) analysis was performed to test whether genetic variants modify these associations. METHODS: A pooled sample of 45 studies including up to 69,734 participants (cases: 29,896; controls: 39,838) of European ancestry were included. To identify G × E interactions, we used the traditional 1--degree-of-freedom (DF) G × E test and to improve power a 2-step procedure and a 3DF joint test that investigates the association between a genetic variant and dietary exposure, CRC risk and G × E interaction simultaneously. FINDINGS: The 3-DF joint test revealed two significant loci with p-value <5 × 10-8. Rs4730274 close to the SLC26A3 gene showed an association with fibre (p-value: 2.4 × 10-3) and G × fibre interaction with CRC (OR per quartile of fibre increase = 0.87, 0.80, and 0.75 for CC, TC, and TT genotype, respectively; G × E p-value: 1.8 × 10-7). Rs1620977 in the NEGR1 gene showed an association with fruit intake (p-value: 1.0 × 10-8) and G × fruit interaction with CRC (OR per quartile of fruit increase = 0.75, 0.65, and 0.56 for AA, AG, and GG genotype, respectively; G × E -p-value: 0.029). INTERPRETATION: We identified 2 loci associated with fibre and fruit intake that also modify the association of these dietary factors with CRC risk. Potential mechanisms include chronic inflammatory intestinal disorders, and gut function. However, further studies are needed for mechanistic validation and replication of findings. FUNDING: National Institutes of Health, National Cancer Institute. Full funding details for the individual consortia are provided in acknowledgments.

The underestimated preventive effects of flexible sigmoidoscopy screening: re-analysis and meta-analysis of randomized trials.

Flexible sigmoidoscopy (FS), which is less invasive, resource intensive and costly than colonoscopy, is among the recommended screening options for colorectal cancer (CRC). Four large randomized trials consistently reported statistically significant, albeit modest effects of screening by FS on CRC incidence. However, their effect estimates included cancers that were already prevalent at recruitment and could not have been prevented by screening. We performed a re-analysis and meta-analysis of two of the trials (including the largest one) to estimate reduction of truly incident cases by a single FS offered between 55 and 64 years of age among the "at risk study population" without prevalent CRC at recruitment. In meta-analyses of data reported after more than 15 years of follow-up, relative risk (95% CI) in intention-to-screen and per-protocol analyses were 0.71 (0.66-0.76) and 0.59 (0.55-0.65) for any CRC, and 0.52 (0.47-0.57) and 0.34 (0.30-0.39) for distal CRC, respectively. These results indicate much stronger effects than those suggested by the original reports and imply that a single screening FS can prevent approximately two out of three distal incident CRC cases within 15 + years of follow-up.

Genetic risk impacts the association of menopausal hormone therapy with colorectal cancer risk.

BACKGROUND: Menopausal hormone therapy (MHT), a common treatment to relieve symptoms of menopause, is associated with a lower risk of colorectal cancer (CRC). To inform CRC risk prediction and MHT risk-benefit assessment, we aimed to evaluate the joint association of a polygenic risk score (PRS) for CRC and MHT on CRC risk. METHODS: We used data from 28,486 postmenopausal women (11,519 cases and 16,967 controls) of European descent. A PRS based on 141 CRC-associated genetic variants was modeled as a categorical variable in quartiles. Multiplicative interaction between PRS and MHT use was evaluated using logistic regression. Additive interaction was measured using the relative excess risk due to interaction (RERI). 30-year cumulative risks of CRC for 50-year-old women according to MHT use and PRS were calculated. RESULTS: The reduction in odds ratios by MHT use was larger in women within the highest quartile of PRS compared to that in women within the lowest quartile of PRS (p-value = 2.7 × 10-8). At the highest quartile of PRS, the 30-year CRC risk was statistically significantly lower for women taking any MHT than for women not taking any MHT, 3.7% (3.3%-4.0%) vs 6.1% (5.7%-6.5%) (difference 2.4%, P-value = 1.83 × 10-14); these differences were also statistically significant but smaller in magnitude in the lowest PRS quartile, 1.6% (1.4%-1.8%) vs 2.2% (1.9%-2.4%) (difference 0.6%, P-value = 1.01 × 10-3), indicating 4 times greater reduction in absolute risk associated with any MHT use in the highest compared to the lowest quartile of genetic CRC risk. CONCLUSIONS: MHT use has a greater impact on the reduction of CRC risk for women at higher genetic risk. These findings have implications for the development of risk prediction models for CRC and potentially for the consideration of genetic information in the risk-benefit assessment of MHT use.

Tissue-specific genetic variation suggests distinct molecular pathways between body shape phenotypes and colorectal cancer.

It remains unknown whether adiposity subtypes are differentially associated with colorectal cancer (CRC). To move beyond single-trait anthropometric indicators, we derived four multi-trait body shape phenotypes reflecting adiposity subtypes from principal components analysis on body mass index, height, weight, waist-to-hip ratio, and waist and hip circumference. A generally obese (PC1) and a tall, centrally obese (PC3) body shape were both positively associated with CRC risk in observational analyses in 329,828 UK Biobank participants (3728 cases). In genome-wide association studies in 460,198 UK Biobank participants, we identified 3414 genetic variants across four body shapes and Mendelian randomization analyses confirmed positive associations of PC1 and PC3 with CRC risk (52,775 cases/45,940 controls from GECCO/CORECT/CCFR). Brain tissue-specific genetic instruments, mapped to PC1 through enrichment analysis, were responsible for the relationship between PC1 and CRC, while the relationship between PC3 and CRC was predominantly driven by adipose tissue-specific genetic instruments. This study suggests distinct putative causal pathways between adiposity subtypes and CRC.

Longitudinal associations of polypharmacy and frailty with major cardiovascular events and mortality among more than half a million middle-aged participants of the UK Biobank.

BACKGROUND: Studies of the associations of polypharmacy and frailty with adverse health outcomes in middle-aged adults are limited. Furthermore, a potentially stronger association of polypharmacy with adverse health outcomes in frail than in non-frail adults is of interest. OBJECTIVE: To evaluate associations of frailty (assessed using a frailty index) and polypharmacy (defined as taking five or more drugs) with major cardiovascular events, cancer incidence, all-cause, cardiovascular disease-specific, and cancer-specific mortality. METHODS: Cox proportional hazards regression models were used to analyze 501,548 participants of the UK Biobank cohort study aged 40-69 years who were followed up for an average of 12 years. RESULTS: The prevalence of pre-frailty and frailty were 43.2 % and 2.3 %, respectively, and that of polypharmacy was 18.3 %. Although strongly associated with each other, frailty and polypharmacy were independently, statistically significantly associated with major cardiovascular events, cardiovascular disease-specific, and all-cause mortality. In addition, the hazard ratios of polypharmacy were stronger among (pre-)frail than non-frail study participants. No profound associations with cancer incidence and cancer mortality were observed. No sex and age differences were observed. CONCLUSIONS: This large cohort study showed that polypharmacy and frailty are independent risk factors for major cardiovascular events, cardiovascular disease-specific and all-cause mortality in both middle-aged (40-64 years) and older people (≥ 65 years). In addition, the hazard ratios of polypharmacy were stronger among (pre-)frail than non-frail study participants. This underlines the need to avoid polypharmacy as far as possible not only in older but also in middle-aged subjects (40-64 years), especially if they are pre-frail or frail.

Personality and the use of cancer screenings - Results of the German National Cohort.

Objective: To determine the association between personality characteristics and use of different cancer screenings. Methods: We used data from the German National Cohort (NAKO; mean age was 53.0 years (SD: 9.2 years)) - a population-based cohort study. A total of 132,298 individuals were included in the analyses. As outcome measures, we used (self-reported): stool examination for blood (haemoccult test, early detection of bowel cancer), colonoscopy (screening for colorectal cancer), skin examination for moles (early detection of skin cancer), breast palpation by a doctor (early detection of breast cancer), x-ray examination of the breast ("mammography", early detection of breast cancer), cervical smear test, finger examination of the rectum (early detection of prostate cancer), and blood test for prostate cancer (determination of Prostate-Specific Antigen level). The established Big Five Inventory-SOEP was used to quantify personality factors. It was adjusted for several covariates based on the Andersen model. Unadjusted and adjusted multiple logistic regressions were computed. Results: A higher probability of having a skin examination for moles, for example, was associated with a higher conscientiousness (OR: 1.07, p < 0.001), higher extraversion (OR: 1.03, p < 0.001), higher agreeableness (OR: 1.02, p < 0.001), lower openness to experience (OR: 0.98, p < 0.001) and higher neuroticism (OR: 1.07, p < 0.001) among the total sample. Depending on the outcome used, the associations slightly varied. Conclusions: Particularly higher levels of extraversion, neuroticism and conscientiousness are associated with the use of different cancer screenings. Such knowledge may help to better understand non-participation in cancer screening examinations from a psychological perspective.

Cigarette smoking and e-cigarette use induce shared DNA methylation changes linked to carcinogenesis.

Tobacco use is a major modifiable risk factor for adverse health outcomes, including cancer, and elicits profound epigenetic changes thought to be associated with long-term cancer risk. While electronic cigarettes (e-cigarettes) have been advocated as harm reduction alternatives to tobacco products, recent studies have revealed potential detrimental effects, highlighting the urgent need for further research into the molecular and health impacts of e-cigarettes. Here, we applied computational deconvolution methods to dissect the cell- and tissue-specific epigenetic effects of tobacco or e-cigarette use on DNA methylation (DNAme) in over 3,500 buccal/saliva, cervical, or blood samples, spanning epithelial and immune cells at directly and indirectly exposed sites. The 535 identified smoking-related DNAme loci (CpGs) clustered into four functional groups, including detoxification or growth signaling, based on cell type and anatomical site. Loci hypermethylated in buccal epithelial cells of smokers associated with NOTCH1/RUNX3/growth factor receptor signaling also exhibited elevated methylation in cancer tissue and progressing lung carcinoma in situ lesions, and hypermethylation of these sites predicted lung cancer development in buccal samples collected from smokers up to 22 years prior to diagnosis, suggesting a potential role in driving carcinogenesis. Alarmingly, these CpGs were also hypermethylated in e-cigarette users with a limited smoking history. This study sheds light on the cell type-specific changes to the epigenetic landscape induced by smoking-related products.

Contributions of early detection and cancer prevention to colorectal cancer mortality reduction by screening colonoscopy: a validated modelling study.

BACKGROUND AND AIMS: Screening colonoscopy, recommended every ten years, reduces mortality from colorectal cancer (CRC) by early detection of prevalent but undiagnosed CRC, as well as by prevention of CRC by removal of precursor lesions. The aim of this study was to assess the relative contribution of both components to total CRC mortality reduction over time. METHODS: Using a validated multistate Markov model, we simulated hypothetical cohorts of 100,000 individuals aged 55-64 with and without use of screening at baseline. Main outcomes included proportions of prevented CRC deaths arising from (asymptomatic) CRC already prevalent at baseline and from newly developed CRC during 15-years of follow-up, and mortality rate ratios of screened versus unscreened groups over time. RESULTS: Early detection of prevalent cases accounted for 52%, 30% and 18% of deaths prevented by screening colonoscopy within 5, 10 and 15 years, respectively. Relative reduction of mortality was estimated to be much larger for mortality from incident cancers than for mortality from cancers that were already present and early detected at screening endoscopy and for total CRC mortality (i.e., 88% versus 67% and 79% within 10 years from screening). CONCLUSIONS: Reduction of CRC mortality mainly arises from early detection of prevalent cancers during the early years after screening colonoscopy, but prevention of incident cases accounts for the majority of prevented deaths in the longer run. Prevention of incident cases leads to sustained strong reduction of colorectal cancer mortality, possibly warranting an extension of screening intervals.

Cancer-specific risk prediction with a serum microRNA signature.

We recently derived and validated a serum-based microRNA risk score (miR-score) that predicted colorectal cancer (CRC) occurrence with very high accuracy within 14 years of follow-up in a population-based cohort study from Germany (ESTHER cohort). Here, we aimed to evaluate associations of the CRC-specific miR-score with the risk of developing other common cancers, including female breast cancer (BC), lung cancer (LC), and prostate cancer (PC), in the ESTHER cohort. MicroRNAs (miRNAs) were profiled by quantitative real-time PCR in serum samples collected at baseline from randomly selected incident cases of BC (n = 90), LC (n = 88), and PC (n = 93) and participants without diagnosis of CRC, LC, BC, or PC (controls, n = 181) until the end of the 17-year follow-up. Multivariate logistic regression models were used to evaluate the associations of the miR-score with BC, LC, and PC incidence. The miR-score showed strong inverse associations with BC and LC incidence [odds ratio per 1 standard deviation increase: 0.60 (95% confidence interval [CI] 0.43-0.82), p = 0.0017, and 0.64 (95% CI 0.48-0.84),p = 0.0015, respectively]. Associations with PC were not statistically significant but pointed in the positive direction. Our study highlights the potential of serum-based miRNA biomarkers for cancer-specific risk prediction. Further large cohort studies aiming to investigate, validate, and optimize the use of circulating miRNA signatures for cancer risk assessment are warranted.

Body size and risk of colorectal cancer molecular defined subtypes and pathways: Mendelian randomization analyses.

BACKGROUND: Obesity has been positively associated with most molecular subtypes of colorectal cancer (CRC); however, the magnitude and the causality of these associations is uncertain. METHODS: We used Mendelian randomization (MR) to examine potential causal relationships between body size traits (body mass index [BMI], waist circumference, and body fat percentage) with risks of Jass classification types and individual subtypes of CRC (microsatellite instability [MSI] status, CpG island methylator phenotype [CIMP] status, BRAF and KRAS mutations). Summary data on tumour markers were obtained from two genetic consortia (CCFR, GECCO). FINDINGS: A 1-standard deviation (SD:5.1 kg/m2) increment in BMI levels was found to increase risks of Jass type 1MSI-high,CIMP-high,BRAF-mutated,KRAS-wildtype (odds ratio [OR]: 2.14, 95% confidence interval [CI]: 1.46, 3.13; p-value = 9 × 10-5) and Jass type 2non-MSI-high,CIMP-high,BRAF-mutated,KRAS-wildtype CRC (OR: 2.20, 95% CI: 1.26, 3.86; p-value = 0.005). The magnitude of these associations was stronger compared with Jass type 4non-MSI-high,CIMP-low/negative,BRAF-wildtype,KRAS-wildtype CRC (p-differences: 0.03 and 0.04, respectively). A 1-SD (SD:13.4 cm) increment in waist circumference increased risk of Jass type 3non-MSI-high,CIMP-low/negative,BRAF-wildtype,KRAS-mutated (OR 1.73, 95% CI: 1.34, 2.25; p-value = 9 × 10-5) that was stronger compared with Jass type 4 CRC (p-difference: 0.03). A higher body fat percentage (SD:8.5%) increased risk of Jass type 1 CRC (OR: 2.59, 95% CI: 1.49, 4.48; p-value = 0.001), which was greater than Jass type 4 CRC (p-difference: 0.03). INTERPRETATION: Body size was more strongly linked to the serrated (Jass types 1 and 2) and alternate (Jass type 3) pathways of colorectal carcinogenesis in comparison to the traditional pathway (Jass type 4). FUNDING: Cancer Research UK, National Institute for Health Research, Medical Research Council, National Institutes of Health, National Cancer Institute, American Institute for Cancer Research, Brigham and Women's Hospital, Prevent Cancer Foundation, Victorian Cancer Agency, Swedish Research Council, Swedish Cancer Society, Region Västerbotten, Knut and Alice Wallenberg Foundation, Lion's Cancer Research Foundation, Insamlingsstiftelsen, Umeå University. Full funding details are provided in acknowledgements.

Automated curation of large-scale cancer histopathology image datasets using deep learning.

BACKGROUND: Artificial intelligence (AI) has numerous applications in pathology, supporting diagnosis and prognostication in cancer. However, most AI models are trained on highly selected data, typically one tissue slide per patient. In reality, especially for large surgical resection specimens, dozens of slides can be available for each patient. Manually sorting and labelling whole-slide images (WSIs) is a very time-consuming process, hindering the direct application of AI on the collected tissue samples from large cohorts. In this study we addressed this issue by developing a deep-learning (DL)-based method for automatic curation of large pathology datasets with several slides per patient. METHODS: We collected multiple large multicentric datasets of colorectal cancer histopathological slides from the United Kingdom (FOXTROT, N = 21,384 slides; CR07, N = 7985 slides) and Germany (DACHS, N = 3606 slides). These datasets contained multiple types of tissue slides, including bowel resection specimens, endoscopic biopsies, lymph node resections, immunohistochemistry-stained slides, and tissue microarrays. We developed, trained, and tested a deep convolutional neural network model to predict the type of slide from the slide overview (thumbnail) image. The primary statistical endpoint was the macro-averaged area under the receiver operating curve (AUROCs) for detection of the type of slide. RESULTS: In the primary dataset (FOXTROT), with an AUROC of 0.995 [95% confidence interval [CI]: 0.994-0.996] the algorithm achieved a high classification performance and was able to accurately predict the type of slide from the thumbnail image alone. In the two external test cohorts (CR07, DACHS) AUROCs of 0.982 [95% CI: 0.979-0.985] and 0.875 [95% CI: 0.864-0.887] were observed, which indicates the generalizability of the trained model on unseen datasets. With a confidence threshold of 0.95, the model reached an accuracy of 94.6% (7331 classified cases) in CR07 and 85.1% (2752 classified cases) for the DACHS cohort. CONCLUSION: Our findings show that using the low-resolution thumbnail image is sufficient to accurately classify the type of slide in digital pathology. This can support researchers to make the vast resource of existing pathology archives accessible to modern AI models with only minimal manual annotations.

Regression-based Deep-Learning predicts molecular biomarkers from pathology slides.

Deep Learning (DL) can predict biomarkers from cancer histopathology. Several clinically approved applications use this technology. Most approaches, however, predict categorical labels, whereas biomarkers are often continuous measurements. We hypothesize that regression-based DL outperforms classification-based DL. Therefore, we develop and evaluate a self-supervised attention-based weakly supervised regression method that predicts continuous biomarkers directly from 11,671 images of patients across nine cancer types. We test our method for multiple clinically and biologically relevant biomarkers: homologous recombination deficiency score, a clinically used pan-cancer biomarker, as well as markers of key biological processes in the tumor microenvironment. Using regression significantly enhances the accuracy of biomarker prediction, while also improving the predictions' correspondence to regions of known clinical relevance over classification. In a large cohort of colorectal cancer patients, regression-based prediction scores provide a higher prognostic value than classification-based scores. Our open-source regression approach offers a promising alternative for continuous biomarker analysis in computational pathology.

Differences in polygenic score distributions in European ancestry populations: implications for breast cancer risk prediction.

The 313-variant polygenic risk score (PRS313) provides a promising tool for breast cancer risk prediction. However, evaluation of the PRS313 across different European populations which could influence risk estimation has not been performed. Here, we explored the distribution of PRS313 across European populations using genotype data from 94,072 females without breast cancer, of European-ancestry from 21 countries participating in the Breast Cancer Association Consortium (BCAC) and 225,105 female participants from the UK Biobank. The mean PRS313 differed markedly across European countries, being highest in south-eastern Europe and lowest in north-western Europe. Using the overall European PRS313 distribution to categorise individuals leads to overestimation and underestimation of risk in some individuals from south-eastern and north-western countries, respectively. Adjustment for principal components explained most of the observed heterogeneity in mean PRS. Country-specific PRS distributions may be used to calibrate risk categories in individuals from different countries.