Expression Profiling Of Differential CircRNAs In Breast Cancer

Background: According to the latest worldwide cancer data in 2020 released by the World Health Organization's International Cancer Research Center,new cases of breast cancer have surpassed lung cancer to become the world's largest cancer.According to a study published on the 14 th Shanghai International Breast Cancer Forum,among the 20,085 breast cancer patients who underwent breast cancer surgery,the five-year disease-free survival rate in stages 0–III was 85.5%,the overall five-year survival rate of breast cancer was as high as 97.9%,and the five-year average survival rates for stage II and III patients were 75% and 61%,respectively.Therefore,in order to improve the cure rate and quality of life of breast cancer patients,the early diagnosis and treatment of breast cancer has become several important.In addition,a large number of studies have proved that many diseases and malignant tumors are closely related to cyclic RNA,thus potentially becoming new potential biomarkers of breast cancer.Methods:(1)High-throughput sequencing technique was used to screen breast cancer and its corresponding para-cancer tissues to obtain differentially expressed circ RNA,and circ RNA with expression level more than 2 times and not reported in the literature was selected as the target gene;Then gene sample theory and path analysis are carried out to predict possible functions;And the cyclic RNA-miRNA interaction is predicted;(2)A breast cancer tissue sample was collected,and the expression level of a target gene in a paired para-cancer tissue was verified by using a qRT-PCR technology.Results:(1)A total of 337 differentially expressed circ RNA in breast can cer tissues were screened out by high-throughput sequencing technique,and Hsa?circ?0016599 was finally selected as the target CIRCRNA according to the screening criteria;(2)The results of gene sample theory and path analysis prediction suggested that the differently expressed circRNA was related to the occur rence,development,proliferation,differentiation of tumors as well as the canceration and apoptosis of cells.(3)The cyclic RNA-miRNA interaction predicts that the five most binding target miRNA sites of hsa?circ?0016599 are hsa-miR-29b-2-5p;hsa-miR-570-5p;hsa-miR-1197;hsa-miR-627-5p;hsa-miR-605-3p,in combination with these miRNAs,thus playing a "miRNA sponge" role.(4)RT-qPCR assay showed that the expression of hsa?circ?0016599 in breast cancer tissues was significantly up-regulated compared with that in the adjacenttis sues(up-regulation rate was 61.5%)with significant difference(P < 0.001),which was consistent with the result of high-throughput sequencing.Conclusion: The results of high-throughput sequencing technique and RT-qPCR indicated that hsa?circ?0016599 was significantly up-regulated in breast cancer tissues as compared with its adjacent tissues.The differently expressed circRNA in breast cancer may play roles in metabolism,transcription process and multiple functional pathways,which provides new clues for further understanding the occurrence and development of breast cancer;Hsa?circ?0016599 can be used as a potential biomarker in the diagnosis of breast cancer.