MTHFD1L and familial pancreatic carcinoma: Next, we tested the expression level of circ-MTHFD1L in human pancreatic cancer cell lines (8988, AsPC-1, BxPC-3, PANC-1, SW1990) and normal human pancreatic duct epithelial cells (HPDE), and we found Compared with normal human pancreatic duct epithelial cells, circ-MTHFD1L was significantly upregulated in pancreatic cancer cells (Fig. 1I).