Given that all CDH1-mutation driven HDGC are SRCCs, and the presence of gastric SRCC is a criterion for CDH1 testing, we employed the SEER database to estimate a postulated risk of secondary cancers among those with sporadic gastric SRCC relative to patients with either any other type of gastric cancer or conventional gastric adenocarcinomas (Table 5). This evidence concerns the gene CDH1 and Familial gastric cancer.