LAUSR

INTRODUCTION Breast cancer can be classified into five subtypes based on variations in the status of three hormonal receptors that are responsible for the cancer's heterogeneity: estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). These classifications influence the choice of therapies (either neoadjuvant or adjuvant), and the range of prognoses, from good (luminal A subtype) to poor (triple-negative cancers). OBJECTIVE The aim of the study was to compare the serum concentration of selected miRNAs (miRNA-21, miRNA-10b, and miRNA-200c) between in two groups of breast cancer patients with differing ER, PR, and HER2 statuses. MATERIALS AND METHODS The study was performed on two groups of patients. One group (TNBC) consisted of patients with triple-negative cancer, and the other group (ER(+)/PR(+)) was comprised of patients with positive ER and PR receptors. RESULTS The mean level of miRNA-200c was significantly higher in the ER(+)/PR(+) group than in the TNBC group (p < 0.05). No statistically significant difference was found between the two groups with regard to the mean levels of miRNA-21 or miRNA-10b. CONCLUSION The level of miRNA-200c was lower in triple-negative patients when compared with the levels in the study's ER/PR positive group.