Pancreas. 2015 Apr;44(3):484-92. doi: 10.1097/MPA.0000000000000280.

Low frequency of KRAS mutation in pancreatic ductal adenocarcinomas in Korean patients and its prognostic value.

Kwon MJ¹, Jeon JY, Park HR, Nam ES, Cho SJ, Shin HS, Kwon JH, Kim JS, Han B, Kim DH, Choi YL.

Author information

¹From the Departments of *Pathology and †Surgery, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang; Departments of ‡Pathology and §Surgery, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul; ¡¬Department of Hematological Oncology, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang; and ¶Laboratory of Cancer Genomics and Molecular Pathology, Samsung Biomedical Research Institute, Samsung Medical Center, #Department of Pathology, Samsung Medical Center, Sungkyunkwan University College of Medicine, and **Samsung Advanced Institute for Health Sciences & Technology, Sungkyunkwan University School of Medicine, Seoul, Korea.

Abstract

OBJECTIVES:

Low prevalence and prognostic relevance of KRAS mutations in Korean pancreatic ductal adenocarcinomas (PDACs) need to be validated with sensitive detection method.

METHODS:

Peptide nucleic acid (PNA)-mediated polymerase chain reaction (PCR) clamping was used to precisely detect KRAS mutation in 72 paraffinized tumor samples and was validated by pancreatic cell lines to compare the efficiency of direct sequencing.

RESULTS:

The PNA-mediated PCR clamping detected mutant allele proportions of as low as 0.5% against a background of wild-type DNA and was 20-fold more sensitive than direct sequencing through the validation of pancreatic cell lines. Peptide nucleic acid-mediated PCR clampingdetected KRAS mutations in 47.2% of 72 PDACs. Low tumor cellularity and low PCR amplification efficiency led to be undetected or failed by direct sequencing in pancreatic paraffinized samples.KRAS mutations were an independent worse prognostic factor predicting a reduced progression-free survival rate in the postoperative chemotherapy group.

CONCLUSIONS:

Peptide nucleic acid clamp real-time PCR was a sensitive method for detecting KRAS status in paraffinized PDAC samples. We identified a low KRAS mutation rate among the Korean PDAC patients using PNA clamp real-time PCR, potentially implicating epidemiological characteristics. The low KRAS mutation rate and its prognostic role may suggest the further survival benefit in Korean PDAC patients.