Hamada T, et al. - Considering the evidence indicating the carcinogenic and immunosuppressive effects of cigarette smoking, researchers examined a differential association of smoking status with risk of colorectal carcinoma subclassified by densities of CD3+ cells, CD8+ cells, CD45RO (PTPRC)+ cells, or FOXP3+ cells during follow-up of 134,981 participants (3,490,851 person-years) in the Nurses’ Health Study and Health Professionals Follow-up Study. Overall, the investigators documented 729 rectal and colon cancer cases with available data on T-cell densities in tumor microenvironment. Outcomes revealed that increased colorectal cancer risk by smoking was stronger for tumors with lower T-lymphocyte response, suggesting an interplay of smoking and immunity in colorectal carcinogenesis.