To examine whether TM4SF1 regulated DDR1 expression in pancreatic cancer cell lines, we transfected siRNA into cells and found that the down-regulation of TM4SF1 could decrease the mRNA and protein expression levels of DDR1 in PANC-1 and AsPC-1 (Fig. 2A,B). This evidence concerns the gene DDR1 and familial pancreatic carcinoma.