CDH1 and gastric adenocarcinoma: 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).