PCDH20 and esophageal squamous cell carcinoma: PCDH20 inhibited non-small cell lung cancer cell (18) and hepatocellular cancer cell (19) but frequently downregulated due to promotor hypermethylation; furthermore, we discovered distinctive PCDH20 expression in adult esophageal tissues and paired cancer tissues; however, the role of PCDH20 in ESCC has never been reported.