CD8A and neoplasm: However, TCGA mainly uses bulk tissue samples, and therefore the data cannot be used to address key questions including how intertumoral and intratumoral heterogeneity develop, how tumor cells and various stromal cell types interact in the TIME, and how certain histological patterns within tumors such as the location of activate CD8+ T cells play an important role in modulating the malignant phenotypes of tumor cells [7,8,9].