Clinical Validation of Newly Developed Multiplex Kit Using Luminex xMAP Technology for Detecting Simultaneous RAS and BRAF Mutations in Colorectal Cancer: Results of the RASKET-B Study

• Published in: Neoplasia (New York, N.Y.) N.Y.), 2018-12, Vol.20 (12), p.1219-1226
• Main Authors: Taniguchi, Hiroya, Okamoto, Wataru, Muro, Kei, Akagi, Kiwamu, Hara, Hiroki, Nishina, Tomohiro, Kajiwara, Takeshi, Denda, Tadamichi, Hironaka, Shuichi, Kudo, Toshihiro, Satoh, Taroh, Yamanaka, Takeharu, Abe, Yukiko, Fukushima, Yoshiyuki, Yoshino, Takayuki
• Format: Article
• Language: English
• Subjects: Colorectal cancer; Colorectal carcinoma; Deoxyribonucleic acid; DNA; Metastases; Mutation; Mutation rates; Paraffin; Patients
• ISSN: 1476-5586; 1522-8002; 1476-5586
• DOI: 10.1016/j.neo.2018.10.004

Detection of RAS and BRAF mutations is essential to determine the optimal treatment strategy for metastatic colorectal cancer (CRC). We prospectively evaluated the MEBGEN RASKET-B KIT (RASKET-B), a novel multiplex kit, simultaneously detecting 48 types of RAS mutations and the BRAF V600E mutation using Luminex xMAP technology. The aim was to obtain market approval for RASKET-B as an in vitro diagnostic (IVD) option in Japan. Genomic DNA was extracted from 302 formalin-fixed paraffin-embedded tissues obtained from CRC patients. The primary endpoints were the concordance rate (CR) between the results from RASKET-B and the previously approved IVD kit (RASKET) for RAS mutations, and CR between the results from RASKET-B and direct sequencing (DS) for BRAF mutations. The secondary endpoints included the CR between RASKET-B and DS for RAS mutations and between RASKET-B and the pyrosequencing (PYRO) for the BRAF V600E mutation. Among the 302 samples, 142 RAS mutations (47%) and 18 BRAF V600E mutations (6.0%) were detected by RASKET-B. All mutations detected in the recruited patients were mutually exclusive. Both RAS and BRAF mutation rates were statistically higher in right-sided than left-sided CRC. The CR between RASKET-B and RASKET for RAS gene and RASKET-B and DS for BRAF V600E mutation was 100% for both (95% CI: 99%-100%). The results from RASKET-B were also highly concordant with DS for RAS (97.4%) and with PYRO for the BRAF (V600E) gene (99.7%). RASKET-B thus provides rapid, precise, and simultaneous detection of RAS and BRAF mutations in CRC.