Hereditary diffuse gastric cancer in a Japanese family with CDH1 mutation three case reports

BackgroundGermline pathogenic variants in the E-cadherin gene CDH1 cause hereditary diffuse gastric cancer (HDGC), which is an autosomal dominant cancer syndrome, accounting for 1-3% of all gastric cancers. HDGC harboring a CDH 1 variant is extremely rare in Japan.MethodIn this study we report the clinical courses of three cases with HDGC from a single Japanese family.ResultsThe proband exhibited advanced and metastatic gastric cancer, and was found to have a previously reported heterozygous frameshift variant in CDH1 (NM_004360.3:c.1009_1010del:p.Ser337Phefs*12). Five at-risk relatives underwent presymptomatic molecular testing after careful genetic counseling, and three were molecularly diagnosed as positive for the variant. Esophagogastroduodenoscopy was performed in these relatives revealing abnormal small pale mucosal patches, small ulcerative lesion and no abnormal findings. Moreover, random and targeted biopsies were compatible with pathological diagnosis of HDGC in the three cases, all of which underwent total prophylactic gastrectomy.ConclusionIt is critical for the assessment and management of HDGC patients to be actively offered a multidisciplinary and familial-oriented approach. Notably, genetic screening in suspected individuals and familial members is a determining piece for a higher detection rate and the identification of clinical relevant mutations in both low and high-incidence gastric cancer countries.

Automated summary

This study reports the clinical courses of three cases with hereditary diffuse gastric cancer in a Japanese family. One patient had advanced and metastatic gastric cancer and was found to have a known heterozygous frameshift variant in the CDH1 gene. Genetic testing for relatives revealed three positive cases, all of whom underwent total prophylactic gastrectomy after abnormal findings in endoscopy.