Long noncoding RNAs (lncRNAs) have been reported to be involved in the development and progression of various human malignancies. However, the role of lncRNA CASC2 in hepatocellular carcinoma (HCC) remains mostly unknown. The aim of this study was to investigate the potential roles and underlying mechanisms of CASC2 in HCC progression. We found that CASC2 expressions were downregulated in HCC tissue samples and cell lines. The clinical assays revealed that lower levels of CASC2 were associated with the TNM stage, lymph node metastasis, and a poorer prognosis specific to HCC patients. Overexpression of CASC2 inhibited the proliferating, migratory, and invasion capacity of HCC cells. Bioinformatics analysis and the luciferase reporter assay revealed that CASC2 worked as a molecular sponge for miR-155. And CASC2 could upregulate SOCS1 expression by inhibiting miR-155 expression in HCC cells. Furthermore, SOCS1 inhibition partially inverses the suppression effect of cell proliferation, migration, and invasion regulated by CASC2 in Huh7 and HepG2 cells. Taken together, our findings identified CASC2 as a tumor suppressor to inhibit HCC development by regulating the miR-155/SOCS1 axis, and CASC2 might be a potential therapeutic target of HCC for future clinical treatment.Copyright © 2023 Ye Yuan et al.