Increased Expression of MicroRNA-155 in the Serum of Women with Early-Stage Breast Cancer

Objective: Because most patients with breast cancer are diagnosed at an advanced disease stage and because prospects for significant improvement in their survival result from early diagnosis, there is a premium on identifying soluble biomarkers that reveal early disease. Recently, a new class of gene-expression regulators known as microRNAs (miRs), which are encoded by miR genes, have emerged and have been linked to various types of cancer. We investigated whether serum micro-RNA 155 (miR-155) could differentiate earlystage breast cancer or the lack thereof in women. Methods: We collected serum samples from 20 female patients recently diagnosed with breast cancer and from 10 healthy women. Quantitative polymerase chain reaction (qPCR) was used to quantify the level of miR-155 expression in all samples. Results: The level of miR-155 expression was significantly higher in the serum of the women with early-stage breast cancer than in that of the healthy control subjects. Conclusion: MiR-155 is significantly elevated in the serum of patients with breast cancer and can be a potential noninvasive molecular marker for early-stage breast cancer screening.