[Current Status and Prospects of the Comprehensive Cancer Genome Profiling].

In June 2019, 2 comprehensive cancer genome profiling(CGP)tests were approved with reimbursement, and are now available at designated hospitals stratified to 3 layers on the basis of their roles. The reimbursement-approved CGP tests were restricted to patients with solid tumors that have progressed on standard chemotherapy, rare tumors, or tumors of unknown primary, and perform primary structure analysis of cancer genome on several hundred genes at a time using next generation sequencer. In tumor molecular board, appropriate treatments were recommended based on the interpretation made for results of CGP. Because 2 CGP tests differ functionally in terms of the sample requirements, the target gene sets, and items to be reported, results need to be evaluated carefully. Although the detection rate of genomic alterations in CGP tests is high, the number of cases lead to treatments consistent with genomic alterations is limited. Improving this ratio will be the key for Japanese precision oncology to meet the full potential of the CGP tests.

Two independent families with strongly suspected hereditary diffuse gastric cancer based on the probands' endoscopic findings.

Hereditary diffuse gastric cancer (HDGC) is the most famous of hereditary gastric cancer syndromes with an autosomal dominant inheritance pattern, and its diagnosis can be made by identifying a pathogenic germline variant in CDH1. We report two independent families that were strongly suspected of having HDGC based on endoscopic findings (multiple tiny, pale areas) obtained in the probands; the probands were pathologically diagnosed as having signet ring cell carcinoma (SRCC) and were genetically confirmed to have a pathogenic CDH1 germline variant. Although the updated International Gastric Cancer Linkage Consortium (IGCLC)'s clinical guidelines for HDGC (2015) state that screening/surveillance endoscopy should be performed (Cambridge protocol), the endoscopic findings obtained in the two presently reported families suggest that pale areas should be suspected as indicating the presence of SRCCs, and biopsies should be performed in addition to obtaining a precise family history in cases suspected of having HDGC.