A successful antitumor immune response requires the following key phases: (1) capture of tumor antigens (or epitopes) by antigen-presenting cells followed by presentation them to lymphocytes; (2) activation and expansion of CD4+ and/or CD8+ lymphocytes; (3) secretion of inflammatory cytokines by CD4+ lymphocytes and destruction of tumor cells by CD8+ lymphocytes with involvement of dendritic cells (DCs), natural killer (NK) cells, and macrophages [10,11]. The gene discussed is CD8A; the disease is neoplasm.