In this study, we assessed the performance of competitive allele-specific TaqMan PCR (castPCR) and digital PCR (dPCR) for the detection of selected KRAS, TP53, SMAD4, and CDKN2A mutations in matched primary tumor tissue and preoperative plasma samples from patients undergoing upfront surgical resection for PDAC. This evidence concerns the gene CDKN2A and neoplasm.