PTEN and esophageal squamous cell carcinoma: Ma et al. [35] investigated the role of microRNA-21 (miR-21) and its regulation on phosphatase and tensin homolog deleted from chromosome-10 (PTEN) in esophageal cancer and demonstrated that miR-21 was overexpressed in vitro and ESCC patients, and promoted cell proliferation by targeting PTEN at posttranscriptional level.