Higher circular RNA_0015278 correlates with absence of extrathyroidal invasion, lower pathological tumor stages, and prolonged disease‐free survival in papillary thyroid carcinoma patients

BACKGROUND: Circular RNA_0015278 (circ_0015278) inhibits the progression of several cancers and is greatly reduced in papillary thyroid carcinoma (PTC) tissues compared with benign thyroid lesions by microarray profiling. This study aimed to further investigate the correlation of circ_0015278 with tumor characteristics and prognosis in PTC patients. METHODS: Totally, 206 PTC patients who underwent tumor resection were retrospectively enrolled; subsequently, circ_0015278 expression in their tumor and adjacent tissues was detected by reverse transcriptional‐quantitative polymerase chain reaction. Besides, disease‐free survival (DFS) and overall survival (OS) were calculated. RESULTS: Circ_0015278 was reduced in tumor tissues compared with adjacent tissues (p < 0.001), and receiver operating characteristic analysis showed that it well discriminated tumor tissues from adjacent tissues (area under curve: 0.903, 95% confidence interval: 0.874–0.932). Besides, higher tumor circ_0015278 expression was correlated with absence of extrathyroidal invasion (p = 0.036), lower pathological tumor (pT) stage (p = 0.05), pathological node (pN) stage (p = 0.002), and pathological tumor‐node‐metastasis (pTNM) stage (p = 0.001). Moreover, higher tumor circ_0015278 expression was associated with a reduced relapse rate (p = 0.011), but not mortality rate (p = 0.110); meanwhile, it was also correlated with prolonged DFS (p = 0.017), but not OS (p = 0.136). Additionally, multivariate Cox's regression analyses showed that higher tumor circ_0015278 expression independently associated with favorable DFS (p = 0.026, hazard ratio = 0.529). CONCLUSION: Circ_0015278 is reduced in tumor tissues, while its’ higher expression in tumor correlates with absence of extrathyroidal invasion, lower pT, pN, and pTNM stage, as well as prolonged DFS in PTC patients.