The diagnostic power of circulating micro ribonucleic acid 34a in combination with cancer antigen 15-3 as a potential biomarker of breast cancer.

To investigate the circulating levels of microRNA-34a (miRNA-34a) as a novel non-invasive biomarker of breast cancer (BC). Methods: The case-control study was conducted at the Department of Chemistry and Biochemistry, College of Medicine, Al-Nahrain University, Baghdad, Iraq, from December 2018 to April 2019. Real-time quantitative polymerase chain reaction has been employed to analyze miRNA-34a expression in the samples of serum from 90 participants (30 patients with BC 30 patients with benign breast tumors and 30 control subjects) after RNA extraction and reverse transcription. Cancer antigen 15-3 (CA15-3) and carcinoembryonic antigen (CEA) were measured by ELISA. Additionally, we analyzed the receiver operating characteristic curves of various markers, including miRNA -34a, CA15-3, and CEA, to assess the diagnostic power of each marker. Results: The expression of miRNA-34a has been significantly lower in the group of breast cancer compared with that in the group of control, and miRNA-34a expression has been significantly reduced in the group of benign breast tumor compared as that in the group of control. Receiver operating characteristics analysis showed a very good discriminative power of combined miRNA-34a and CA15-3 (specificity=77.7%; sensitivity=83.3% and areas under the curve =0.842) for BC patients. Conclusion: MicroRNA-34a expression is significantly decreased in the patients' serum with the cancer of breast, and miRNA-34a can be employed as a potential non-invasive molecular marker for the early diagnosis of BC.