Association of KRAS G12D mutation with outcome in patients with pancreatic cancer after surgery.

Abstract

221 Background: The frequency of KRAS gene mutations in pancreatic adenocarcinoma is high and most mutations occur in codon 12 and 13. However, the association of KRAS mutation status with clinical outcome of pancreatic cancer patients after surgery is not clearly understood. The aim of present study was to clarify whether presence of mutation in KRAS is of prognostic significance, and to determine whether the different type of KRAS mutation have different impact on clinical outcome in pancreatic cancer. Methods: A total of 62 pancreatic adenocarcinoma tissues from patients underwent curative surgery were analyzed for KRAS mutation. DNA was extracted from the tissue microarray. The domain containing the KRAS gene codons 12 and 13 was amplified by PCR, and KRAS mutation was detected by loop hybrid mobility shift assay (LH-MSA). Results: KRAS mutation was detected in 41 of 62 tumors (66.1%). Mutations of KRAS codon 12 and codon 13 were detected in 37 of 62 tumors (59.7%) and in 4 of 62 tumors (6.5%), respectively. G12D mutation were detected in 35.5% (22/62) and G12V mutation in 19.4% (12/62) of all. The patients with KRAS mutations had a significantly shorter overall survival (OS) (log rank, p=0.0375) and disease free survival (DFS) (p=0.0175). When the type of mutation were evaluated, G12D mutation was significantly associated with both shorter OS (p=0.0410) and DFS (p=0.0214), whereas G12V mutation was associated with neither OS (p=0.6727) nor DFS (p=0.9854). Conclusions: The presence of KRAS mutation was significantly associated with poor outcome of pancreatic cancer patients after surgery. A specific mutation G12D demonstrated significant association with shorter OS and DFS in pancreatic cancer. The different type of KRAS mutation might have different impact on clinical outcome in pancreatic cancer.