TGFB1 and neoplasm: TS/A exerts a suppressive effect on the host immune response through several mechanisms, such as a selective loss of STAT5a/b expression in T and B lymphocytes [26], the production of transforming growth factor β1 (TGF-β1) [18], the induction of regulatory T cells [27], natural killer resistance [36] and the production of colony stimulating factors (CSFs) that deeply subvert hematopoiesis [14,15], giving rise to splenomegaly, leucocytosis and to tumor-infiltrating myeloid-derived suppressor cells (MDSC) [29,33,53].