P-383 Analysis of microsatellite and RAS/RAF status in Tunisian colorectal cancer series

Therapeutic strategies for colo-rectal relies on several parameters among which microsatellite (MS) and RAS/RAF status have important value. The aim of our study was to analyze combined MS in colorectal carcinoma (CCR). We a series 73 cases CCR with nodal/visceral metastasis. determined by immunohistochemistry. Molecular testing performed the RT-PCR automatized Idylla system. 67 were MS-proficient; 38 mutated : 30 KRAS mutated, 4 NRAS BRAF mutated. Six patients MS-deficient rectal carcinoma, 2 remaining colic wild type cases. Our found that MSI/RAS/RAF is rare (9.5%) meanwhile both MSS cases, representing worst prognostic group, represent 40%