HHLA2 and familial pancreatic carcinoma: Interestingly, Yan et al26 reported HHLA2 expression in inflamed ducts in peritumoural tissues in 10% of pancreatic cancer patients, while normal duct epithelial cells do not express HHLA-2, suggesting that inflammation can induce HHLA-2 expression on pancreatic ductal epithelial cells.