The MAPK-ERK, as well as PI3K-AKT signaling transduction pathway, represents a pivotal function in tumorigenesis. Genetic alterations of potential tumor-driven genes, for instance, KRAS, BRAF, NRAS, and PIK3CA can result in uncontrolled cell proliferation and progression. The main aims of the study were not only to identify the prevalence of KRAS, BRAF, NRAS, PIK3CA molecular modifications but also to evaluate the relationship between gene changes and clinical and/or pathological characteristics of 251 Vietnamese colorectal cancer. Genetic abnormalities on KRAS, BRAF, NRAS, and PIK3CA were detected through the utility of Realtime PCR, Pyrosequencing, and Direct sequencing methods, respectively. The frequency of KRAS, BRAF, NRAS, and PIK3CA mutations were 34.3%, 6.4%, 7.2%, and 17.5%, in turn. KRAS mutation was mutually exclusive against that of NRAS and BRAF mutations in CRC. BRAF, as well as RAS/RAF mutations, were more usual in older age. A significant association between PIK3CA mutations and age together with differentiation of CRC was determined. In addition, PIK3CA mutation tended to coexist with KRAS but not with NRAS and BRAF mutation. Our results indicate the information of molecular markers that contribute to self-sufficient oncogenic mechanisms in the carcinogenesis of CRC.
Key words: KRAS, NRAS, BRAF, PIK3CA mutations, colorectal cancer (CRC)
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