SERPINB5 and familial pancreatic carcinoma: One of these genes is the serine protease inhibitor SERPINB5 (Maspin), that has been reported as completely unmethylated in 87% of pancreatic cancer cell lines (20/23), 94% of xenografts (32/34) and hypomethylated in 86% of primary pancreatic adenocarcinomas (6/7), with an inverse correlation between methylation and mRNA expression level [57].