EGFR and KRAS Mutations in Non-Small Cell Lung Cancers: A Pilot Study from Turkey
S Bircan, H Baloglu, Z Kucukodaci, A Bircan. Suleyman Demirel University Faculty of Medicine, Isparta, Turkey; Gulhane Medical Academy Haydarpasa Teaching Hospital, Istanbul, Turkey
Background: Mutation profile of the MAPK pathway in non-small cell lung cancers (NSCLC) shows wide variations because of many factors including geographic and ethnic background. There is no data denoting EGFR and KRAS mutations of NSCLC cases about Turkey in the literature. We aimed to screen the frequency and the types of EGFR and KRAS mutations in a sample group of NSCLC cases in Turkey, and we compared our data to the available literature to realize weather geographic and ethnic factors has any implication.
Design: Fourteen adenocarcinomas (AC), 11 squamous cell carcinomas (SCC) were screened for EGFR exon 19 and 21, and KRAS exon 2. Pure tumor tissues from formalin fixed paraffin embedded tumor tissues were used for DNA extraction. After PCR amplifications, sequence data were analyzed and compared to the literature findings according to frequency, site and type of mutations detected.
Results: We found 11 (44%) cases with EGFR mutations (exon 19; n=8 and exon 21; n=5) and 6 (24%) cases with KRAS mutations in NSCLC cases. For EGFR exon 19, we detected frame or frame shift deletion type mutation in all cases. For EGFR exon 21, 3 cases were found with L858R mutation (CTG>CGG) and in 2 cases deletion type mutations were detected. While all 5 cases were revealing codon 12 mutations (3 patients G>T; 1 patient T>C; 1 patient G>A), only one case was detected with codon 13 mutation (G>T) in KRAS gene. As the histological types, in AC group, 5 cases with EGFR (exon 19; n=3 and exon 21; n=3) and 3 cases with KRAS exon 2 mutations were detected. Mutations in the SCC group were distributed as 5 exon 19 and 2 exon 21, and 3 KRAS mutations. Additionally, KRAS and EGFR mutations were observed together only in 3 patients (2AC and 1SCC), and EGFR 19 and 21 mutations were detected together only in 2 cases (1AC, 1SCC).
Conclusions: The mutation frequency and the site profiles of KRAS in our small series of Turkish non-small cell lung cancer patients were found quite similar to those seen in the western countries. However, the EGFR mutations were distinctive in terms of frequency, than the westerns, and were quite similar to that of East Asian.
Tuesday, March 23, 2010 9:30 AM
Poster Session III # 255, Tuesday Morning