CD8A and neoplasm: Given that CD4+ T and CD8+ T cells, but not B cells, were highly infiltrated in ATO-treated tumors (Figures 4F and 4G), we explored the indispensability of CD4+ and CD8+ T cells, which are two key immune cell subsets that coordinate antitumor immune responses,32 in the tumor suppression function of the reactivated p53-R279W.