Long noncoding RNAs can serve as oncogenes or tumor suppressors in human cancer; however, their biological functions and underlying mechanism in hepatocarcinogenesis are largely unknown. Here, we report a novel tumor suppressor long noncoding RNA on chromosome 8p12 (termed TSLNC8 ) that is frequently deleted and down‐regulated in hepatocellular carcinoma (HCC) tissues. The loss of TSLNC8 is highly associated with the malignant features of HCC and serves as a prognostic indicator for HCC patients. TSLNC8 significantly suppresses the proliferation and metastasis of HCC cells in vitro and in vivo . TSLNC8 exerts its tumor suppressive activity by competitively interacting with transketolase and signal transducer and activator of transcription 3 (STAT3) and modulating the STAT3‐Tyr705 and STAT3‐Ser727 phosphorylation levels and STAT3 transcriptional activity, thus resulting in inactivation of the interleukin‐6–STAT3 signaling pathway in HCC cells. Conclusion: TSLNC8 is a promising prognostic predictor for patients with HCC, and the TSLNC8–transketolase–STAT3 axis is a potential therapeutic target for HCC treatment. (H epatology 2018;67:171‐187).

Long noncoding RNA TSLNC8 is a tumor suppressor that inactivates the interleukin‐6/STAT3 signaling pathway