PTRH2 and esophageal squamous cell carcinoma: To test whether Bit1 downregulation affected cell growth in ESCC, MTT assay and nude mice xenografts were utilized to investigate the effects of Bit1 knockdown on cell growth in ESCC, we found that Bit1 downregulation markedly suppressed cell growth in vitro and in vivo, implying Bit1 functions tumor suppressor in ESCC.