Observations that inflammatory cell density is higher in tumor tissue than in non-adjacent normal tissue in breast cancer patients [3] and that histologic distributions of CD4 and CD8 T cell subsets in, for instance liver metastases of colorectal cancer, can be correlated with clinical stage and outcome in colorectal cancer patients [4] emphasize that there is a topography to tumor control by the immune system. The gene discussed is CD4; the disease is colorectal cancer.