CEACAM5 and cancer: To verify that 5a-HSA can efficiently inhibit TGFβ activation mediated by αvβ6- or αvβ8-positive cancer cells, we investigated the effect of 5a-HSA, *HSA (a negative control protein), and peptide 5a and 2a (a negative control peptide) on TGFβ production by WEHI-164, TS/A, TRAMP-C2, 5M7101/GFP/CEA, and 5637 cancer cells.