Higher miR-21 expression in invasive breast carcinomas is associated with positive estrogen and progesterone receptor status in patients from Serbia

Abstract

MicroRNAs play essential role in breast carcinoma progression and invasion. Our principal goals were to assess clinicopathological and prognostic correlations of microRNA-21 (miR-21) expression levels in a group of 39 Serbian breast cancer patients with invasive lobular (ILC), ductal (IDC), or mixed (ILC-IDC) breast carcinomas and in order to discover the role of miR-21 in potential novel form of stratification of the patients with different estrogen receptor (ER) and progesterone receptor (PR) status. MiR-21 expression levels were measured by stem-loop real-time RT-PCR using TaqMan technology. ER, PR, human epidermal growth factor 2 receptor (Her-2), and proliferative index (Ki-67) were evaluated by immunohistochemistry. MiR-21 levels do not vary among ILC, IDC, and ILC-IDC subgroups. MiR-21 expression levels varied significantly in the age, tumor size, Ki-67, and different grade (p = 0.030, p = 0.036, p = 0.027 and p = 0.032, respectively) subgroups. ER+ and PR+ showed higher miR-21 levels than their negative receptor status paired groups ER- and PR- with p = 0.012 and p = 0.018, respectively. MiR-21 positively correlated with ER and PR status (p = 0.018, ρ = 0.379 and p = 0.034, ρ = 0.345, respectively). Our findings suggest that miR-21 emulates transitional form of expression and that the levels of expression might be useful for stratification of the patients with different receptor status with the purpose to seek for new therapy approaches especially for the patients with the lack of response to conventional endocrine therapy.

MicroRNAs Expression in Triple Negative vs Non Triple Negative Breast Cancer in Tunisia: Interaction with Clinical Outcome

“…In fact, it was described that miR-21 is involved in positive hormonal breast carcinoma especially in those expressing HER2 that upregulate miR-21 and, therefore, it is involved in positive hormonal breast cancer subtypes since it appeared to interact with the α ER pathway [33], [34], [35]. However, according to our results, we found that this microRNA is more expressed in the negative hormonal receptors among the Tunisian population.…”

microRNA Regulation in Estrogen Receptor-Positive Breast Cancer and Endocrine Therapy

“…Indeed, the development of targeted therapeutics to upregulate these particular tumor suppressor miRNAs may serve as a promising strategy to treat ER + breast cancer. In contrast, several oncomiRs have consistently been reported to be upregulated in ER + breast cancer, such as miR-10b and miR-21 [ 4 – 6 ]. In particular, the tumor suppressor PTEN , which dephosphorylates PIP 3 and in turn blocks PI3K/Akt signaling, is a direct target of many oncomiRs that are overexpressed in ER + breast cancer (Table 1 ).…”

MicroRNA-21 induces breast cancer cell invasion and migration by suppressing smad7 via EGF and TGF-β pathways

“…invasion and migration, as well as TGF-β-mediated invasion and migration in breast cancer cells and these effects were due to miR-21-induced downregulation of smad7. miR-21 is expressed at high levels in cancer cells in invasive breast cancers (35) and findings of previous studies (including our previous study) have shown that miR-21 plays an important role in breast cancer metastasis (36)(37)(38). In the present study, miR-21 was overexpressed in the plasma of patients with breast cancer, demonstrating that miR-21 plays an important role in cancer cell invasion and migration, as metastasis, indicating that plasma miR-21 levels may serve as a diagnostic marker in breast cancer.…”

“…Thus, miR-21 facilitated deleterious cross-talk between EGF and TGF-β in a manner that promotes breast cancer cell invasion and migration. Given that miR-21, EGFR and TGF-β are often overexpressed in breast cancers (12,18,20,26,35,39), these observations suggest that suppression of miR-21 may prevent invasion and possibly metastasis in breast cancers, while interrupting deleterious EGF-TGF-β interactions that have the potential to contribute to breast cancer cell proliferation in vivo.…”