Clinical significance of monitoring KRAS in tissue and plasma of pancreatic cancer patients.

Abstract

745 Background: KRAS monitoringprovides valuable information for early diagnosis and prediction of treatment outcome in colorectal cancer. KRASmutation is observed in only half of colon cancer patients, whereas it is detected in 90% of pancreatic cancer patients. Therefore, investigating tumor DNA in plasma by KRAS monitoringmay be even more valuablein pancreatic cancerpatients. In this study, we elucidated the clinicalsignificance of KRASmonitoring in pancreatic cancer patients during treatment. Methods: KRASin tumor tissues was analyzed for mutations by Scorpion ARMS or RASKET in 83 patients with pancreatic tumors. KRASin plasma was analyzed for mutations(G12D, G12V, G12C, G12A, G12S, G12R, G13D, Q61L, and Q61H) using droplet digital polymerase chain reaction in 88 patients who underwent the curative surgery (N = 45) or the chemotherapy (N = 33) and who had KRAS mutation in their tissues. Results: KRASmutation in tumor tissues was detected in 74 of 83 patients (89.2%). These 74 patients showed significantly poorer prognosis (MST; 32) than the seven patients without mutation (p = 0.03), whose MST were 193. Monitoring of KRASin plasma revealed KRASmutation in 35 of 88 patients (39.8%). In patients who underwent the chemotherapy (N = 33), 2years OS of patients who detected KRASmutation in plasma (N = 23) was 16.4% and them which not detected it (N = 10) was 53.3% (p = 0.18). But in the curative resection group (N = 45), 3years OS of patients who detected KRASmutation in plasma (N = 12) was 16.7% and them which not detected it (N = 33) was 68.2% (p = 0.00). Conclusions: KRASmutation in tissue and plasma could be a valuable predictive and prognostic biomarker in pancreatic cancer patients.