The Profile of MicroRNA Expression and a Group of Genes in Breast Cancer: Relationship to Tumor Progression and Immunohistochemical Status

A current approach of oncogenomics is the search for genes with expression that makes it possible to specify the type of breast cancer (BC) and the prognosis of the disease due to different tumor status. By real-time PCR analysis on a 41 BC samples set, the relationship between mRNA expression levels of five tumor-associated genes (BCL6, CHL1, AXL, ACSL1, TGFB2) and seven potentially regulatory microRNAs (miR-132-3p, miR-137, miR-148a-3p, miR-219-5p, miR-24-2-5p, miR-339-3p, miR-375) to clinical and pathological parameters of tumors and immunohistochemical status was characterized. A decrease in the expression level of CHL1 and AXL and an increase in the expression level of BCL6 revealed in the late stages of breast cancer were shown. In addition, stages III and IV of breast cancer are associated with an increase in the miR-339-3p expression level, and lymph node metastases are associated with a decrease in the miR-148a-3p expression level. It was noted that a high rate of Ki-67 proliferation is related to an increase in the miR-375 expression level. Tumors that do not express the progesterone receptor (PR) show decreased expression levels of BCL6, miR-375, and miR-24-2-5p. A decreased expression level of BCL6 was also observed in breast cancer with a negative estrogen receptor (ER–) status. In breast cancer samples with a negative HER2 status, a statistically significant decreased expression level of the gene TGFB2 and miR-219-5p was noted, and also a decreased expression level of TGFB2 was found in luminal A of BC. Thus, we identified possibly new molecular indicators of breast cancer progression and biomarkers that can be useful in the differential diagnosis of the molecular subtype of breast cancer.