RESUMO
BACKGROUND: Breast cancer (BC) is one of the most prevalent cancers in developing and developed countries among women worldwide. Mammography is one of the superior methods for BC detection, but it carries up to 20% false-negative results, especially in early cases. Histological examination of tissue biopsies and fine-needle aspiration cytology are invasive techniques. Hence, minimally invasive markers are needed for the improved detection of BC. microRNAs, small, noncoding, single-stranded RNAs functioning as tumor suppressor genes or oncogenes, are attractive biomarkers for early detection. This study aimed to examine the serum levels of miR21 and miR10b in patients with BC especially in the early stages compared to healthy controls to evaluate their potential use as BC biomarkers. METHODS: This study included 90 females who were divided into two groups. Group I included 70 patients with BC and was subdivided into group Ia with 40 nonmetastatic BC patients and group Ib with 30 metastatic BC patients. Group II included 20 apparently healthy females as a control group. Serum miR21 and miR10b as biomarkers and miR16 as a housekeeping gene were evaluated using real-time polymerase chain reaction. RESULTS: The median levels of miR10b and miR21 were statistically significantly upregulated in the sera of patients with BC compared to healthy controls (P = 0.001). Receiver operating characteristic curve analyses demonstrated that serum levels of miR10b and miR21 were useful biomarkers for distinguishing between patients with BC and the control group, with an area under the curve (AUC) of 0.991 with 97.1% sensitivity and 100% specificity at a cutoff of 3.1 for miR10b and an AUC of 0.965 with 95.7% sensitivity and 85% specificity at a cutoff of 1.7 for miR21. Regarding the early stages of BC, the median levels of the fold change of serum miR21 and miR10b were statistically significantly higher in patients with BC (stages I and IIa) than in the control group (P < 0.001). CONCLUSIONS: Both miR21 and miR10b have valuable diagnostic roles in detecting the early stages of BC.
