As for protein level, flow cytometry was utilized to test CD45RO fluorescence intensity of CD8+ T lymphocytes (Figure 3H) and statistical data showed that Median Fluorescence Intensity (MFI) of CD45RO decreased in CD8+ T cells from ccRCC tissues (p < 0.0010) (Figure 3I). Here, CD8A is linked to nonpapillary renal cell carcinoma.