CD8A and cancer: Several previous studies have shown that the high-grade density of CD8+ T cells in cancer cell nests was correlated with prognosis [49], and the presence of tumor infiltrating lymphocytes (TILs) was able to predict a better survival as an independent prognostic factor in various types of cancers including malignant melanoma [50], ovarian cancer [51], breast cancer [52], oral squamous cell carcinoma [53], esophageal cancer [54], and colon cancer [55].