As the most important immunoglobulin in humoral immunity, IgG can specifically recognize antigens, activate the complement killing mechanism, and enhance the phagocytosis and killing effect of macrophages on tumor cells, while IgM can effectively activate complement-mediated phagocytosis and killing function of phagocytes, and IgA mainly plays a mucosal protection role. The gene discussed is CD79A; the disease is neoplasm.