Gene Mutation Profile of Pancreatic Cancer in Japanese Patients and Its Association with Prognosis

Gene Mutation Profile of Pancreatic Cancer in Japanese Patients and Its Association with Prognosis

Annals of Oncology 25 (Supplement 5): v44–v74, 2014 doi:10.1093/annonc/mdu435.79 Oral Session (Oral presentations categorized by each organ) O2 9 5...

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Annals of Oncology 25 (Supplement 5): v44–v74, 2014 doi:10.1093/annonc/mdu435.79

Oral Session (Oral presentations categorized by each organ) O2

9

5

Hideyuki Hayashi1,2,3, Hideki Ueno1, Yasunari Sakamoto1, Shunsuke Kondo1, Chigusa Morizane1, Kazuaki Shimada4, Hitoshi Ichikawa5, Nobuyoshi Hiraoka6, Takashi Kohno2, Takuji Okusaka1 1 Department of Hepatobiliary and Pancreatic Oncology, National Cancer Center Hospital 2 Division of Genome Biology, National Cancer Center Research Institute 3 Department of Gastroenterology and Hepatology, Hokkaido University Graduate School of Medicine 4 Department of Hepatobiliary and Pancreatic Surgery, National Cancer Center Hospital 5 Division of Genetics, National Cancer Center Research Institute 6 Division of Molecular Pathology, National Cancer Center Research Institute

abstracts

Background: Activating KRAS mutations are the major driver gene aberrations of pancreatic cancer and are present in over 90% of patients with pancreatic cancer. On the other hand, aberrations of the CDKN2A, TP53, and SMAD4 genes are also frequent

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GENE MUTATION PROFILE OF PANCREATIC CANCER IN JAPANESE PATIENTS AND ITS ASSOCIATION WITH PROGNOSIS

events in pancreatic carcinogenesis. We constructed a mutation profile of pancreatic cancer-associated genes. Additionally, we analyzed the relationship between gene mutations and clinicopathological factors. Methods: Genomic DNA samples were extracted from fresh frozen surgical specimens obtained from 100 patients (98 with pancreatic ductal adenocarcinoma, 2 with adenosquamous carcinoma) who underwent radical operations for pancreatic cancer at the National Cancer Center Hospital between March 2005 and June 2012. Next-generation sequencer-based targeted deep sequencing was performed using a Cancer Panel reagent that covers representative cancer-related genes (50 genes, 190 hot spots). Results: Mutations were detected in 97% of the cases, and the average number of mutations per tumor sample was 1.6. The most frequently mutated genes were KRAS (96%), TP53 (42%), SMAD4 (13%), and CDKN2A (7%) in our cohort. The known druggable mutations that were detected were GNAS (1%), PIK3CA (1%), and KIT (1%). Among the patients who underwent radical operations followed by adjuvant chemotherapy (71 patients), the survival of patients who had 0 to 2 mutations in the 4 major driver genes (KRAS, TP53, SMAD4, and CDKN2A) was significantly longer than that of patients who had 3 or more mutations (median overall survival, 40.0 months vs. 12.6 months, P = 0.0020). A multivariate Cox proportional hazard model analysis showed that a low number of mutations among these 4 genes was significantly associated with a better prognosis. Conclusions: KRAS, TP53, SMAD4, and CDKN2A were the most frequently mutated genes in Japanese patients with pancreatic cancer. The number of mutations among these 4 genes as detected using targeted deep sequencing may be a useful biomarker for the prediction of postoperative outcomes.