GPX1 and pancreatic ductal adenocarcinoma: The relationship between GPX1 and resistance remains less clear and appears to have some tissue-dependence; with increased activity promoting resistance in Non-Small Cell Lung Cancer (NSCLC) and breast carcinoma while lower GPX1 expression drives gemcitabine resistance in pancreatic ductal adenocarcinoma (PDAC) [[25], [26], [27]].