Hossein Ayatollahi - Cancer Molecular Pathology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
Alireza Tavassoli - Endoscopic and Minimally Invasive Surgery Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
Amir Hossein Jafarian - Dept. of Pathology, Cancer Molecular Pathology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
Amin Alavi - Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran

Background & objective: KRAS mutations are reported in many types of cancers including pancreas, lung, colon, breast, and gastric (GC). High frequency of KRAS mutation is observed in the pancreas, colon, and lung cancers; they commonly arise in codon 12 and 13 of exon 2. Due to the lack of information about the frequency of KRAS mutations in the Northeast of Iran, the current study aimed at evaluating KRAS frequency in cases with GC in this region. Methods: A total of120 formalin-fixed, paraffin-embedded blocks of patients with GC were assessed. The assays to detect KRAS in codon 12 and 13 were obtained through the peptide nucleic acid (PNA)-clamp. Results: Totally 87 male and 33 female patients were analyzed in the current study. The mean age of the subjects was 55 years. The most common tumoral fragment was located on the body with 48 cases (40%) and the less frequent was related to fondues with six cases (5%). Of the 120 GC samples, 16 (13.3%) cases had codon 12 KRAS mutation, and 16.7% had codon 13 mutations. There were no significant relationships between gender, age, and KRAS mutations in the studied specimens. Conclusion: In conclusion, the overall frequency of KRAS codon 12 and 13 mutations in GC was 30% in the current study population. Frequency of KRAS codon 12 and 13 mutations had significant correlation with tumors location. Different pathogenic mechanisms are suggested for GC according to tumor location. The current study results may be an important diagnostic tool for physicians managing atrophic gastritis.

KRAS, Codon 12 and 13, Gastric Cancer