Associations of red and processed meat intake with major molecular pathological features of colorectal cancer.

Red and processed meat is an established risk factor for colorectal cancer (CRC). However, exact mechanisms to explain the associations remain unclear. Few studies have investigated the association with CRC by molecular tumor features, which could provide relevant information on associated molecular pathways. In this population-based case-control study from Germany (DACHS), 2449 cases and 2479 controls provided information on risk factors of CRC and completed a food frequency questionnaire. Multivariable logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CI) for the associations between meat intake and risk of CRC by molecular pathologic features and specific subtypes. Red and processed meat intake was associated with increased risk of colorectal (>1 time/day vs ≤1 time/week OR 1.66, 95% CI 1.34-2.07), colon and rectal cancer. Among the single molecular tumor features investigated, the results were similar for associations of red and processed meat with CRC risk by microsatellite instability, CpG island methylator phenotype, BRAF, oestrogen receptor-β and p53 status. Red and processed meat intake was associated less strongly with risk of KRAS-mutated CRC (OR >1 time/day vs ≤1 time/week: 1.49, 95% CI 1.09-2.03) than with risk of KRAS-wildtype CRC (OR 1.82, 95% CI 1.42-2.34; p heterogeneity 0.04). These results support an association between red and processed meat and CRC risk similar for subsites of CRC and most of the investigated major molecular pathological features. Potential differences were observed in more specific subtype analyses. Further large studies are needed to confirm these results and to help further elucidate potential underlying mechanisms.