Abstract

Introduction: Papillary thyroid carcinoma (PTC) with metastasis has a poor prognosis and requires effective prognostic markers. Because long non-coding ribonucleic acid (lncRNA) HCG4 is abnormally expressed in thyroid cancer, this study investigated its prognostic value for PTC and its regulatory mechanisms. Material and methods: This study included 128 patients with PTC. The prognostic value of HCG4 was assessed using Kaplan–Meier curves. COX analysis was used to identify prognostic factors affecting PTC. HCG4 and miR-146b-5p levels in tissues and cells were assessed using real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR). Cell proliferation was detected using a cell counting kit (CCK-8 kit). Cell invasion and migration were assessed using a Transwell assay. The binding relationship between HCG4 and miR-146b-5p was detected using dual-luciferase reporter (DLR). Results: HCG4 levels were reduced in PTC tissues, and cells compared with normal tissues, while miR-146b-5p levels were increased. PTC patients with low HCG4 levels demonstrated lower 5-year survival rates, and HCG4 also serves as an independent protective prognostic factor for PTC. HCG4 negatively regulates the level of miR-146b-5p. HCG4 overexpression inhibits cell proliferation, invasion, and migration abilities of the cells. These abilities were restored by increasing the level of miR-146b-5p. Therefore, increasing HCG4 could reduce the level of miR-146b-5p, thereby alleviating PTC development. Conclusions: HCG4 demonstrates favorable prognostic value. Overexpression of HCG4 can reduce the level of miR-146b-5p, inhibit the survival rate and invasiveness of PTC cells, and thereby potentially alleviate the progression of PTC.