CD8A and neoplasm: Antigen-specific memory T cells are classified into central memory (Tcm) and effector memory T cells (Tem) subsets, and Tem subsets (CD3+CD8+CD62L-CD44+) located in lymphoid and non-lymphoid tissues can respond quickly when exposed to the same tumor antigen and provide immediate protections by producing cytokines (e.g., TNF-α and IFN-γ).