Notably, this pro-metastatic effect of ITGA1 was much less apparent in the absence of TGFβ/collagen pre-treatment and co-xenografting (Supplemental Fig. 6), demonstrating a TGFβ/collagen microenvironment-specific role for ITGA1 in pancreatic cancer progression. This evidence concerns the gene TGFB1 and familial pancreatic carcinoma.