In another study, the presence of stromal fibroblasts increased pancreatic cancer cell expression of a set of genes linked to tumor cell invasion, including cyclooxygenase 2 (COX-2)/prostaglandin-endoperoxide synthase 2 (PTGS2), hyaluronan synthase 2 (HAS2), and matrix metalloproteinase-1 (MMP-1) [50]. This evidence concerns the gene PTGS2 and familial pancreatic carcinoma.