TGFB1 and neoplasm: Instead, in pre-BCG tumors with Th1-profiled TILs, other immunosuppressive mechanisms, such as secretion of TGF-β, PGE2, IL-10, and IL-6, as well as accumulation of myeloid-derived suppressor cells, tumor-associated macrophages, and regulatory T cells, could contribute to creating a highly tolerogenic TME [31].