Association of microRNA-93, 190, 200b and receptor status in core biopsies from stage III breast cancer patients.

Oncologists now favor more personalized treatment strategies in breast cancer patients. Gene expression analysis has been widely used, but less is known about epigenetic factors, for example, microRNAs (miRNAs). The aim of this study was to determine the relationship between selected miRNAs and receptor status in core biopsies sampled before preoperative chemotherapy in stage III locally advanced breast cancer (LABC) patients. In 37 LABC core biopsies, three miRNAs per sample were analyzed: hsa-miR-93-5p, hsa-miR-190a, and hsa-miR-200b-3p, and hsa-miR-103a-3p as an endogenous control (TaqMan(®) RT-PCR; Applied Biosystems). Receptor status was determined by a dedicated pathologist. The Mann-Whitney U, Shapiro-Wilk, and Levene's tests were used to compare related samples. Levels of miRNA-93 differed significantly in core biopsies of LABC patients with different expressions of ER (estrogen receptor) and PR (progesterone receptor). Higher levels of miRNA-93 were found in ER-negative (p=0.0027) and PR-negative patients (p=0.0185). Levels of miRNA-190 and 200b did not differ significantly in core biopsies of LABC patients who expressed ER and PR differently (p=0.7727, p=0.9434, p=0.6213, and p=0.1717). Levels of miRNA-93, 190, and 200b were not significantly different in core biopsies of LABC patients with different HER2 (human epidermal growth factor 2) expressions (p=0.8013, p=0.2609, and p=0.3222). The assessment of core biopsy miRNA profiles and receptor-based subtypes may identify new signaling pathways for improved breast cancer classification.