Determination of circulating microrna-155, let-7C, microrna-21 levels as A non-invasive biomarker in differential diagnosis and prognosis of idiopathic granulomatous mastitis and breast cancer

Idiopathic granulomatous mastitis (IGM) is a benign breast disease that clinically mimics breast cancer (BC). MicroRNAs (miRNAs) play important role in the development and prognosis of various diseases including cancer. In recent studies, miRNAs have been recommended as biomarkers in the diagnosis of diseases. Phosphatase and tensin homolog (PTEN) is a tumor suppressor gene that regulates many cellular functions such as cell growth, proliferation, and is regulated by miRNAs. In this study, it was aimed to determine and evaluate circulating miR-155, let-7c, miR-21 and PTEN levels in order to be used in differential diagnosis of patients with IGM and BC. 45 patients with BC, 50 patients with IGM and 48 healthy volunteers were included in the study. Serum miRNA levels were measured by RT-PCR and PTEN levels by ELISA. Fold changes of miRNAs were calculated by 2-ΔΔCt method. Serum miR-21 expression was significantly higher in BC (fold change=2.42) and IGM group (fold change=1.33) compared to control (p<0.001). Serum miR-155 and let-7c expression levels were significantly lower in both groups compared to the control group (p<0.001). MiR-21 expression in BC was significantly higher than IGM (fold change=1.976) (p<0.001). PTEN levels in BC were significantly higher than IGM (p<0.001); significantly lower than the control group (p<0.001); IGM group was significantly lower than control group (p<0.001). Moderate negative correlation was found between PTEN and miR-21 expression level in BC (r=-0.490;p<0.001). In the differential diagnosis of BC and IGM, serum miR-21 (AUC=0.806;p<0.001) and PTEN (AUC=0.877;p<0.001) levels were found to be statistically significant. In addition to radiological data, serum miR-21 and PTEN levels may be non-invasive biomarkers that can help differentiate IGM from BC. The results of the study will lead to future studies in the differential diagnosis of IGM and BC.