In many types of cancers, TGF-β1 is overexpressed by carcinoma cells (Ronnov-Jessen et al, 1996; Rowley, 1998), and it has been proposed previously that the expression of this cytokine by breast and prostate carcinoma cells induces reactive stroma (Ronnov-Jessen et al, 1996; Rowley, 1998; Webber et al, 1999). This evidence concerns the gene TGFB1 and cancer.