A Panel of Serum Noncoding RNAs for the Diagnosis and Monitoring of Response to Therapy in Patients with Breast Cancer

Background: The aim of this study was to identify a panel of serum noncoding RNAs (ncRNAs) as potential diagnostic and prognostic biomarkers for breast cancer. Material/Methods: Patients with breast cancer (n= 30), and normal controls (n= 0) were included in the 'training set.' A 'validation set' included cases of breast cancer (n=128) and controls (n=77). All cases provided blood samples for serum analysis. All cases of breast cancer were confirmed histologically and were staged. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) was used to detect the expression of 11 candidate ncRNAs, including long noncoding RNAs (lncRNAs) and microRNAs (miRNAs), in the serum. The expression of the panel of ncRNAs was further analyzed following surgery or chemotherapy. Results: The four ncRNAs identified in the serum of patients with breast cancer included let-7a, miR-155, miR-574-5p, and metastasis-associated lung adenocarcinoma transcript 1 (MALAT1). Analysis based on the risk score showed that the panel of these four ncRNAs could effectively distinguish between patients with breast cancer and the control group. For the training set and the validation set, analysis of the receiver-operating characteristic (ROC) curve showed that the areas under the curve (AUCs) were 0.960 and 0.968, respectively. Also, the serum expression levels of the four ncRNAs differed in the pre-treatment and the post-treatment patients with breast cancer, with levels of miR-155 showing a significant decrease following chemotherapy. Conclusions: A panel of serum ncRNAs, including let-7a, miR-155, miR-574-5p, and MALAT1, was shown to be present in patients with breast cancer.