The immune system is increasingly recognized as a critical factor in ovarian cancer outcomes [188] and consists of both innate immunity (mediated, in part, by macrophages, NK leukocytes, complement, dendritic cells [DCs], MDSCs) and adaptive immunity (mediated, in part, by CD8+ cytotoxic T cells [Tc], CD4+ helper T cells [Th], thymic and peripheral regulatory T cells [Treg], T helper 17 (Th17) effector cells, CD3 + CD56+ NK-like T cells, B cells) [189]. The gene discussed is CD4; the disease is ovarian cancer.