KRAS and pancreatic ductal adenocarcinoma: Pancreatic ductal adenocarcinoma (PDAC) has been reported to be an NRG1 fusion-enriched tumor; the overall incidence of NRG1 + PDAC is estimated to be 0.48% [11], and the incidence of NRG1 + PDAC seems to be enriched in KRAS-wild-type PDAC [24, 25].