Qayyum A, Nagi AH, Khadim MT, Naveed AK, Jehan S, Majeed A, Sabar MF, Suhail Razak.
Absence of KRAS mutations in codons 12, 13 in colorectal adenocarcinoma from northern Pakistan.
Biomedica Jan ;32(3):155-9.

Background and objectives:KRAS mutations have been studied in various malignancies in many researches conducted on various populations.The objective of this research was to document the KRAS oncogenic mutation pattern particularly in codons 12 and 13 in Northern Pakistani patients of colorectal adenocarcinoma (CRA) presented in Armed Forces Institute of Pathology (AFIP) Rawalpindi. Place and Duration of Study: Armed Forces Institute of Pathology (AFIP), Rawalpindi. Research was completed in approximately four years from 2011 to 2015. Methods: It was a cross – sectional study with non-probability convenience sampling performed in a period from January 2010 to April 2015. A total of 181 cases of CRA who underwent intestinal resection were studied. Sections from both tumor and normal intestine for control purpose were prepared. DNA was extracted and PCR was performed with specific primers. Amplified PCR products of 50 samples were analyzed on 1.5% agarose gel. DNA sequencing was done in Centre for Applied Molecular Biology, Lahore. Results: Among the samples, 75% were males and 25% females with age ranging from 15 to 90 years (mean age 54.68 ± 16.89 years). Higher average age was found to have high tendency to acquire colorectal adenocarcinoma and rectosigmoid was found to be the most important site. Tumors were mostly exophytic, moderately differentiated with majority showing no lymphovascular invasion. No KRAS oncogenic mutation was seen including codons 12 and 13. Conclusion: The KRAS gene mutations in codon 12 and 13 are either absent in CRA patients of northern area of Pakistan or their frequency may be very low.These cases may be due to mutations of some other genes or because of some non-genetic environmental factors.

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