KRAS and neoplasm: The possible mechanism of carcinogenesis is as follows: KRAS, TP53, CDKN2A, and SMAD4 mutations cause pancreatic intraepithelial neoplasia (PanIN), a precancerous lesion of PDAC, and epithelial-mesenchymal transition (EMT) occurs during the process of invasive growth of tumor cells, whereby pleiomorphic cells are formed, resulting in the development of ACP [43–46].