Low expression of long non-coding RNA GAS5 is associated with poor prognosis of patients with thyroid cancer.

The study aims to investigate the role of long non-coding RNA (lncRNA) GAS5 in the diagnosis and prognosis of patients suffering from thyroid cancer (TC). A total of 212 patients with TC and 61 patients with benign thyroid tumor were enrolled in the study. Quantitative real-time polymerase chain reaction (qRT-PCR) was applied to detect the lncRNA GAS5 expression in TC and benign tumor tissues. All TC patients were categorized into high-risk and low-risk groups according to the MACIS, AGES and AMES prognostic scoring system. A 5-year follow-up was conducted in order to determine the disease free survival (DFS) rates and overall survival (OS) rates. The associations between lncRNA GAS5 expression and prognosis of TC patients were analyzed by The Kaplan-Meier survival curves and the Cox regression models. There was a decrease in the lncRNA GAS5 expression in TC tissues in comparison to benign tumor tissues. Expression of lncRNA GAS5 showed significant association with tumor node metastasis (TNM) staging, lymph node metastasis and the multiple cancer foci of TC. AMES high-risk patients showed a decreased expression of lncRNA GAS5 expression than the AMES low-risk patients. The AGES and MACIS high-risk patients showed lower lncRNA GAS5 expression than low-risk patients. The survival rate of TC patients with high lncRNA GAS5 expression was higher than that of TC patients with low lncRNA GAS5 expression during the DFS and OS periods. Cox regression analysis indicated that lncRNA GAS5 expression, TNM staging, lymph node metastasis and multiple cancer foci were independent risk factors for poor prognosis in TC patients. LncRNA GAS5 may be closely related to the diagnosis and prognosis of TC.