SUN-029 Circular RNA Profile of Parathyroid Neoplasms: Analysis of Co-Expression Networks of Circular RNAs and mRNAs

Circular RNAs (circRNAs) are a recently identified class of non-coding RNAs participating in multiple biological process and tumor progress. However, the expression of circRNAs in parathyroid carcinoma (PCa) and parathyroid adenoma (PAd) remains unknown. The expression profile of circRNAs was assessed by microarray in tissues of 6 parathyroid carcinomas, 6 adenomas and 4 normal parathyroid glands. A circRNA-mRNA network was constructed to explore the possible significance of circRNAs in the parathyroid carcinoma. Moremore, the expression of circRNAs and corresponding mRNAs were validated in a cohort of parathyroid neoplasms by quantitative reverse transcription polymerase chain reaction (RT-qPCR). Compared to the normal parathyroid, the differentially expressed circRNAs were as many as 5310 in PCa and 1055 in PAd. Among these differentially expressed circRNAs, the expression of four circRNAs, including hsa_ circRNA_0035563 (p=0.006), hsa_circRNA_0017545 (p=0.009), hsa_circRNA_0001687 (p=0.005) and hsa_circRNA_0075005 (p=0.001), and four mRNAs (MYC, FSCN1, ANXA2 and AKR1C3) was then confirmed by RT-qPCR. Consequently, hsa_circ_0075005 was the most promising diagnostic marker to distinguish PCa from PAd, with the AUC value of 0.770 (p=0.001) via receiver operator characteristic curve analysis. Furthermore, high expression level of hsa_circ_0035563 was found to be related with the CDC73 mutations (p=0.022), as well as the disease recurrence in the patients with PCa (p=0.042). In conclusion, this is the first study to reveal the expression profile of circRNAs in parathyroid neoplasms. The hsa_circ_0075005 and MYC mRNA may be used as novel diagnostic markers for PCa. High expression level of hsa_circ_0035563 was found to be related with the CDC73 mutations and disease recurrence in the patients with PCa, but the detailed molecular mechanisms of their pathogenic contribution are still in need of further investigation.