NRAS and KRAS testing by a new diagnostic method to detect point mutations in colorectal cancer specimens: Clart-NRAS iKRAS.

e22159 Background: RAS family mutation status is an important potential clinical variable for treatment visitation in metastatic colon cancer (mCRC). Around 40% of colorectal tumors carry mutations in KRAS exon 2 (codons 12 and 13) which is a negative predictor of response to anti-EGFR therapies. Recent studies extend the range of mutations to include KRAS exons 3 and 4 or NRAS exons 2, 3 as negative response outcome predictors to anti-EGFR-containing therapy. Here, we present a novel diagnostic assay based upon multiplex ARMS-PCR and microarray detection system (CLART technology) to identify infrequent KRAS and NRAS mutations in formalin fixed paraffin embedded CRC specimens. Methods: We designed specific ARMS-primers and hybridization probes for detecting Q61H (183 A>C), K117N (351 A>C), K117N (351 A>T), A146T and A146V mutations in KRAS; and G12D, Q61H (183 A>T), Q61L, Q61N and Q61R mutations in NRAS. Clinical testing was performed using 33 clinical samples which contained the targets of this assay. Mo...