GNAS and tubular adenocarcinoma: Previous studies had reported that when the gastric subtype transformed into malignant tumor, it mainly developed into invasive tubular adenocarcinoma that had much poorer prognosis than the invasive adenocarcinoma originating from the nongastric type.[18,19] In addition, pancreatic ductal adenocarcinoma might mainly arise in the pancreas with benign gastric-type IPMN, in the absence of GNAS mutations.[18,20] In our study, 71.4% of the gastric subtype invasive IPMNs were tubular adenocarcinoma, which was close to the pancreatobiliary subtype (77.8%) and the intestinal subtype (66.7%).