Clinicopathological characteristics and mutational profile of KRAS and NRAS in Tunisian patients with sporadic colorectal cancer.

BACKGROUND/AIM Colorectal cancer (CRC) is a major public health problem worldwide and in Tunisia due to its increasing incidence. KRAS and NRAS mutations have become a pivotal part of CRC diagnosis, given their association to treatment resistance with anti-epidermal growth factor receptor (EGFR) monoclonal antibodies. We aim to screen for mutations in KRAS and NRAS genes in Tunisian patients with CRC and to explore their correlations with clinicopathological features. MATERIALS & METHODS AmoyDx KRAS and NRAS mutation real-time PCR kits were used to screen for mutations in KRAS (exon 2) and NRAS (exons 2, 3 and 4) in 96 CRC tumors. RESULTS KRAS exon 2 mutations were found in 41.7% (40/96) of the patients. Codon 12 most abundant mutations were G12D and G12V followed by G12A, while G13D is the predominant mutation in codon 13. KRAS exon 2 mutations were associated with older patients (p = 0.029), left-sided tumors (p = 0.037) and greater differentiation (p = 0.044). The prevalence rate of NRAS mutations was 7.3%, mostly in exon 2. These mutations were associated with early stages (p = 0.039) and the absence of lymph node metastasis (p = 0.045). CONCLUSION It can be inferred from this study that Tunisian CRC patients have a similar frequency of KRAS and NRAS mutations compared to those observed in other populations. Consequently, screening for KRAS and NRAS mutation is crucial to orientate the therapies and the selection of an appropriate candidate, avoiding patients? unnecessary toxicity and costs.