Evaluation of microRNA-155 as a diagnostic serum-based biomarker in patients with breast cancer

Abstract

Background Breast cancer (BC) is the most common cancer among Egyptian women, and its early detection is accompanied with decreased mortality rates. MicroRNAs (miRNAs) are small noncoding RNA molecules that regulate gene expression and affect cancer development. The expression level of miRNA-155 is up-regulated in BC and correlates with its invasive properties, offering a great potential as a noninvasive biomarker for BC screening. Objective The aim of this study is to evaluate the role of miRNA-155 as an early diagnostic serum-based biomarker of BC. Patients and methods This study was conducted on 30 patients newly diagnosed with BC and associated 20 healthy women as a control group. Serum level of miRNA-155 was measured for all studied cases using real-time quantitative PCR technique. Results MiRNA-155 expression was up-regulated in serum of patients with BC compared with control group (P<0.001). Serum miRNA-155 expression significantly differed with cancer stage and its expression directly increased with advancing cancer stage. A comparative study of the miRNA-155 expression between control group and positive and negative metastatic lymph nodes (LNs) subgroups demonstrates a highly significant difference. MiRNA-155, in terms of fold change, is highest in positive LNs metastatic subgroup, with a mean of 19.63, followed by 4.29 in negative LNs metastasis subgroup, and lowest in the control group, with a mean of 1.06 (P<0.001). Conclusion The results validate miRNA-155 as a promising diagnostic and even a prognostic marker in cases of BC.

Keywords

• breast cancer
• early diagnosis of breast cancer
• microrna-155