Although some tumor cells do not express MHC-II, it has previously been shown that CD4+ T cells can still mediate rejection of these MHC-II-deficient tumors through indirect mechanisms and there is also evidence for the development of a CD4+ T cell anti-tumor memory compartment in breast cancer patients and in the B16 melanoma mouse model (198, 207–209). The gene discussed is CD4; the disease is melanoma.