CDH1 (also known as epithelial cadherin (E-cadherin), a member of the cadherin- catenin complex, is an example in which pathogenic variants can lead to CLP and/or gastric cancer. The human CDH1 gene consists of 16 exons that span 100 kb. Classical cadherins are a family of single-span transmembrane domain glycoproteins that primarily mediate calcium-dependent cell–cell adhesion, which are differentially expressed throughout the body. Cadherins are single-membrane-spanning proteins with a divergent extracellular domain of five repeats and a conserved cytoplasmic domain. Much experimental evidence suggests that the CDH1 is a tumor suppressor and alterations in its expression are linked with multiple tumor types and its clinicopathological features. Loss of CDH1 is used for the diagnosis and prognosis of epithelial cancers.