Mutation in KRAS and BRAF Genes in Helicobacter pylori-Infected Patients with Gastric Cancer and Peptic Ulcer

Helicobacter pylori are the main cause of various gastroduodenal diseases. It is estimated that approximately half of the planet population is infected with H. pylori. KRAS and BRAF genes are the targets of genetic changes in H. pylori-infected patients with gastric cancer (GC) and peptic ulcer (PU). The high frequency of these mutations represents their high potential as a biomarker in early diagnosis of GC. The current study aimed at evaluating the frequency of KRAS (Kirsten Rat Sarcoma) and BRAF (BRAF proto-oncogene) gene mutation status in H. pylori-infected patients with GC and PU. The current cross-sectional and descriptive study was conducted on 80 paraffin-embedded sections including 40 gastric adenocarcinoma and 40 PU tissue samples. The samples were collected from April 2017 to March 2018. H. pylori were identified and confirmed in all samples using the IHC (immunohistochemical) method and the histopathology of all PU and GC tissue samples was available. After DNA extraction from paraffin-embedded sections, and polymerase chain reaction, KRAS and BRAF gene mutations were assessed using the direct sequencing method, and the correlation of mutations and clinicopathological characteristics was also studied. KRAS mutation was observed in codon 12 (n = 7; 17.5%) and BRAF mutation in codon V600 (n = 4; 10%) in patients with GC. No KRAS and BRAF mutations were observed in patients with PU. Results of the current study also showed that the majority of the examined samples belonged to male patients (70%) and female patients constituted 30% of the samples; patients mean age was 48.95 ± 12.11 years. No significant correlation was observed between the mutations and pathological manifestations (age, gender, and tumor grade). KRAS and BRAF gene mutations were revealed in H. pylori-infected patients with GC.