Calcium intake and risk of colorectal cancer according to tumor infiltrating T cells
Menée à partir des données de 2 cohortes incluant au total 88 509 femmes et 47 740 hommes (durée de suivi : 32 ans), cette étude évalue l'association entre l'apport de calcium et le risque de cancer colorectal, selon la densité intratumorale de lymphocytes T
Calcium intake has been associated with a lower risk of colorectal cancer. Calcium signaling may enhance T cell proliferation and differentiation, and contribute to T-cell mediated antitumor immunity. In this prospective cohort study, we investigated the association between calcium intake and colorectal cancer risk according to tumor immunity status to provide additional insights into the role of calcium in colorectal carcinogenesis. The densities of tumour-infiltrating T-cell subsets (CD3+, CD8+, CD45RO (PTPRC)+, or FOXP3+ cell) were assessed using immunohistochemical and computer-assisted image analysis in 736 cancer cases that developed among 136,249 individuals in two cohorts. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards regression. Total calcium intake was associated with a multivariable HR of 0.55 (comparing ≥1200 vs. <600 mg/day, 95% CI, 0.36-0.84; ptrend=0.002) for CD8+ T-cell-low but not for CD8+ T-cell-high tumours (HR=1.02, 95%CI, 0.67-1.55; ptrend=0.47). Similarly, the corresponding HRs (95 CIs) for calcium for low vs. high T-cell infiltrated tumours were 0.63 (0.42-0.94; ptrend=0.01) and 0.89 (0.58-1.35; ptrend=0.20) for CD3+; 0.58 (0.39-0.87; ptrend=0.006) and 1.04 (0.69-1.58; ptrend =0.54) for CD45RO+; and 0.56 (0.36-0.85; ptrend=0.006) and 1.10 (0.72-1.67; ptrend=0.47) for FOXP3+, although the differences by subtypes defined by T cell density were not statistically significant. These potential differential associations generally appeared consistent regardless of sex, source of calcium intake, tumor location, and tumor microsatellite instability status. Our findings suggest a possible role of calcium in cancer immunoprevention via modulation of T cell function.