Long non-coding RNA CASC15 is upregulated in hepatocellular carcinoma and facilitates hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer, accounting for one-sixth of all malignant tumors, and the mortality rate of HCC ranks second among all cancer-related deaths. Increasing evidence has recently shown that long non-coding RNAs (lncRNAs) play an important role in cancer occurrence and progression, including HCC. Cancer susceptibility candidate 15 (CASC15), a lncRNA, has been reported to be involved in melanoma progression and phenotype switching. However, the function of CASC15 in human HCC is still unknown. In the present study, we evaluated expression of CASC15 and its potential functions in HCC. The expression of CASC15 in HCC tissues was quantitated by the reverse-transcription quantitative polymerase chain reaction, which showed that CASC15 was overexpressed in 59% (48/82) of HCC tissues compared with corresponding adjacent normal tissues, and the CASC15 expression level was significantly correlated with metastasis (P=0.012), tumor size (P=0.037), and TNM stage (P=0.013). Kaplan-Meier survival curves showed that high CASC15 expression was associated with poor prognosis in HCC patients (P<0.05). Moreover, a knockdown model of CASC15 was established, which showed that CASC15 significantly impaired HCC cell proliferation, migration, and invasion. CASC15 knockdown also induced cell apoptosis in vitro and impaired tumor growth in vivo. In conclusion, CASC15 plays an important role in the progression of HCC, acting as an oncogene. High expression of CASC15 is correlated with a poor prognosis, suggesting that CASC15 may be a predictive biomarker of HCC.