CD4 and neoplasm: T cell responses have been measured and have been found to be relevant also in other models of oncogene addiction, as in a recent study demonstrating that CD4+ T cells are required for tumor regression upon inactivation of the MYC or BCR–aBL oncogenes in mouse models of T cell acute lymphoblastic lymphoma and pro-B cell leukemia, respectively (Rakhra et al., 2010).