PTPN9 promotes cell proliferation and invasion in Eca109 cells and is negatively regulated by microRNA-126.

Protein tyrosine phosphatase non-receptor type 9 (PTPN9), also named PTP-MEG2, is an important member of the protein tyrosine phosphatase family that is involved in variety of human diseases. However, the role of PTPN9 in esophageal squamous cell carcinoma (ESCC) remains to be established. The present evaluated the potential effect and underlying mechanism of action of PTPN9 in ESCC. Immunohistochemistry was performed to detect PTPN9 protein expression in 84 ESCC tumor specimens and 30 normal esophageal tissues. The association between positive expression of PTPN9 and clinicopathological features and prognosis was analyzed. The prognostic role of PTPN9 was further investigated using multivariate regression analysis. PTPN9-small interfering RNA and microRNA (miR-126)-mimics were transfected into Eca109 cells to construct PTPN9 silencing and an miR-126 ectopic expression cell model. Reverse transcription-quantitative polymerase chain reaction, western blot analysis, cell counting kit-8, Transwell assays and flow cytometry were used to investigate the role of PTPN9 in the process of ESCC progression and its potential downstream signaling pathway. Immunohistochemical analysis revealed that PTPN9 was upregulated in ESCC tumor specimens compared with normal esophageal tissues. The χ