Prognostic significance of resident CD103+CD8+T cells in human colorectal cancer tissues

The prognostic significance and clinical implications of resident CD103⁺CD8⁺T cells in human colorectal cancer tissues still remains largely unexplored. In our present study, we aimed to characterize the resident CD8⁺T cells in human colorectal cancer tissues by using double staining of CD103 and CD8, and further evaluated the prognostic significance of resident CD8⁺T cells in colorectal cancer. We found that the OS rate of the colorectal cancer patients with higher infiltration of CD8⁺T cells, or with higher numbers of resident CD103⁺CD8⁺T cells, or with higher ratio of CD103⁺CD8⁺T cells over total CD8⁺T cells in cancer tissues was significantly better than that of the patients with lower infiltration of CD8⁺T cells, or with lower numbers of resident CD103⁺CD8⁺T cells, or with higher ratio of CD103⁺CD8⁺T cells over total CD8⁺T cells in cancer tissues, respectively. Moreover, higher infiltration of CD8⁺T cells in colorectal cancer tissues was significantly and inversely correlated with advanced TNM stage. Higher numbers of resident CD103⁺CD8⁺T cells in colorectal cancer tissues were significantly and inversely correlated with distant metastasis status. Higher ratio of CD103⁺CD8⁺T cells over total CD8⁺T cells in colorectal cancer tissues was significantly and inversely correlated with age status. The COX model analysis demonstrated that higher infiltration of CD8⁺T cells, higher numbers of resident CD103⁺CD8⁺T cells, or higher ratio of CD103⁺CD8⁺T cells over total CD8⁺T cells in colorectal cancer tissues, could serve as independent prognostic predictors for colorectal cancer patients. Taken together, our present study demonstrated the density of tumor infiltrating CD8⁺T cells or the numbers of resident CD103⁺CD8⁺T cells in colorectal tissues could be used as an important prognostic predictor for this malignancy.