TGFB1 and carcinoma: The pivotal role of αVβ6 integrin in latent TGF-β activation in carcinoma is concluded from several lines of evidence: firstly, KAT-4 cells activated latent TGF-β and transferred the active growth factor to target cells by an αVβ6-dependent process; Capan-2 cells, however, were unable to activate latent TGF-β unless they were co-cultured with human F99 fibroblasts.