Yasuyuki Suzuki

Purpose KRAS , P16 , TP53 , and SMAD4/DPC4 mutations are common in pancreatic ductal adenocarcinoma (PDAC). The study aimed to evaluate the association between gene mutations in pre‐treatment endoscopic ultrasound‐guided fine needle aspiration (EUS‐FNA) samples and clinical outcomes of patients with PDAC. Methods There were 43 patients with resectable (R) PDAC and 41 patients with borderline resectable (BR) PDAC. CDKN2A/p16 , TP53 , and SMAD4/DPC4 were evaluated through immunohistochemistry (IHC) of pretreatment EUS‐FNA ( n = 84) and resected specimens ( n = 71). All patients received neoadjuvant therapy. Results IHC of EUS‐FNA specimens revealed p16 loss in 61 (73%), abnormal p53 in 61 (73%), and Smad4 loss in 38 (45%) patients. Abnormal p53 was associated with a lower resection rate ( p = .017). Abnormal p53 and Smad4 loss were associated with recurrence within 6 months post‐pancreatectomy ( p = .03, p = .03, respectively). Univariate Cox regression analysis was conducted to reveal that abnormal p53 ( p = .07), p16 loss and abnormal p53 ( p = .04), and Smad4 and p16 loss ( p = .03) were associated with poor prognosis. Conclusions Pre‐treatment abnormal labeling of p53 in EUS‐FNA specimen was associated with a lower resection rate and an early recurrence in R or BR PDAC cases.