Based on those theories, we speculate that although CD8+ T-lymphocyte content was higher in cases of CRC with advanced stage, poorer differentiation, and higher Ki67 expression, significantly fewer CD8+ T lymphocytes actually exerted anti-tumor effects because of the continuous cancer antigen stimulation, transformation of CD8+ T-cell subtypes, serious immune dysfunction and rejection. This evidence concerns the gene CD8A and colorectal carcinoma.