[New Classification for Advanced Colorectal Cancer Using CancerPlex®Genomic Tests].

: Recently, targeted drugs have been developed for the treatment of colorectal cancer(CRC). Among targets, it is well known that KRAS mutations are associated with resistance to epidermal growth factor receptor(EGFR)monoclonal antibodies. However, response rates using anti-EGFR monotherapy for CRC were less than 20-30% in previous clinical studies. Thus, because the RAS/MAP2K/MAPK and PI3K/AKT pathways are associated with CRC resistance to chemotherapy, we analyzed gene mutations in Stage IV CRC patients using a genomic test(CancerPlex®). Medical records were reviewed for 112 patients who received treatment for CRC between 2007 and 2015 in Niigata University Medical and Dental Hospital or Niigata Cancer Center Hospital. There were 66 male and 46 female patients, and their median age was 62.5(range, 30-86) years. Cluster analyses were performed in 110 non-hypermutated Japanese CRC patients using Euclidean distance and Ward's clustering method, and 6 typical groups were identified. Among these, patients with all wild-type actionable genes benefited from anti-EGFR therapies. The expense of targeted drugs warrants consideration of cost-effectiveness during treatment decision-making for advanced CRC patients. To this end, based on the genetic information on CRC, it is possible to develop precision medicine using CancerPlex®.