Homologous to the poliovirus receptor (PVR/CD155), the Nectin immunoglobulin superfamily comprises four known isoforms, Nectin 1, 2, 3 and 4 (also designated TSLC1). TSLC1 is encoded by a tumor-suppressor gene in human non-small-cell lung cancer mapping to chromosome 11q23.2. The TSLC1 protein is an N-linked membrane glycoprotein that co-localizes with the Actin filament-binding protein, afadin, at cadherin-based adherens junctions in MDCKII epithelial cells. TSLC1 also interacts with the tumor-suppressor gene product DAL-1 (for differentially expressed in adenocarcinoma of the lung protein 1) to target Actin rearragement and cellular motility. TSLC1 may also form homodimers that function in homophilic, intracellular adhesion. TSLC1 expression is reduced or absent in a number of characterized cancer cell lines including A549. In prostate and breast cancer, as well as in pancreatic ductal adenocarcinoma, the TSLC1 promoter is commonly silenced by hypermethylation. Unlike other Nectins, which are more widely expressed, TSLC1 is mainly expressed in the placenta.