Antigen presentation in the tumor context may favor Treg expansion: in a mouse model of spontaneous prostate cancer, an efficient Treg induction/expansion occurred only when TCR-transgenic, antigen-specific CD4 T cells encountered the cognate antigen expressed in the context of prostate cancer cells, rather than non-transformed cells or viral vector-infected cells (91). This evidence concerns the gene CD4 and prostate carcinoma.