Abstract
Tumor markers are defined as antigens specifically expressed in tumor cells or tissues that can be utilized for pathological diagnosis. Here we propose that host immune and/or inflammatory cells could be used as tumor markers because they could predict the biological malignancy of tumors. First we showed that CD8+ T cells infiltrated within cancer cell nests in colorectal cancer could be a novel prognostic factor as revealed by both uni− and multivariate analyses; the more CD8+ cells, the better the survival rate. This was also a clinicopathological demonstration of anti−tumor immunity. Next we showed that macrophages along the invasive margin could function to suppress hematogenous metastasis because these cells were smaller in number in cases with simultaneous or metachronous hematogenous metastasis. These macrophages expressed costimulatory molecules B7−2, HLA−DR, CD40, and CD11c, sharing a phenotype with dendritic cells, representative antigen presenting cells. This suggests their involvement in tumor immunity. Our data indicate that lymphocytes and macrophages could influence the biological malignancy of colorectal cancer.
