High Frequency of Codon 12 but not Codon 13 and 61 K-ras Gene Mutations in Invasive Ductal Carcinoma of Breast in a South Indian Population

Background: Ras genes are thought to play an important role in human cancer since they have been foundto be activated frequently in several types of tumors including breast cancer, where the overall incidence ofK-RAS oncogene activation is 0-10%. Evaluation of K-RAS gene not only for mutational frequency but also formutation types in this downstream signaling gene pathway is necessary to determine the mechanisms of action.The present study was conducted to test the hypothesis that K-RAS activation is involved in breast cancer riskof south Indian population. Materials and
Methods: A total of 70 paired pathologically confirmed tumor andnon-tumor tissues from the same breast cancer patients were analysed for most common K-RAS mutationsof codon 12,13 and 61 by polymerase chain reaction followed by restriction digestion and direct nucleotidesequencing method.
Results: We found that a high rate of homozygous and heterozygous mutations of codon 12,but not codon 13 and 61, may influence the invasive ductal carcinoma of breast risk in this study.
Conclusions:Our study indicated that only codon 12 may be involved in initiating breast carcinogenesis in India.