Yang W, et al. - Researchers performed this prospective cohort study to determine whether calcium intake is associated with colorectal cancer risk according to tumor immunity status, and to provide additional insights into the role of calcium in colorectal carcinogenesis. They used immunohistochemical and computer-assisted image analysis to assess the densities of tumor-infiltrating T-cell subsets (CD3+, CD8+, CD45RO (PTPRC)+, or FOXP3+ cell) in 736 cancer cases that developed among 136,249 individuals in two cohorts. Findings revealed an association of total calcium intake with a multivariable HR of 0.55 (comparing ≥ 1,200 vs < 600 mg/day) for CD8+ T-cell-low, but not for CD8+ T-cell-high tumors (HR=1.02). Likewise, the analogous HRs for calcium for low vs high T-cell infiltrated tumors were 0.63 and 0.89 for CD3+; 0.58 and 1.04 for CD45RO+; and 0.56 and 1.10 for FOXP3+. However, there were no statistically significant differences by subtypes defined by T-cell density. Findings suggest that, via modulation of T-cell function, calcium may play a possible role in cancer immunoprevention.