Down-regulation of traditional oncomiRs in plasma of breast cancer patients

Abstract

Deregulated expression of microRNAs has the oncogenic or tumor suppressor function in cancer. Since miRNAs in plasma are highly stable, their quantification could contribute to more precise cancer diagnosis, prognosis and therapy prediction. We have quantified expression of seven oncomiRs, namely miR-17/92 cluster (miR-17, miR-18a, miR-19a and miR-20a), miR-21, miR-27a and miR-155, in plasma of 137 breast cancer (BC) patients. We detected down-regulation of six miRNAs in patients with invasive BC compared to controls; however, only miR-20a and miR-27a down-regulations were statistically significant. Comparing miRNA expression between early and advanced stages of BC, we observed statistically significant decrease of miR-17 and miR-19a. We identified down-regulation of miR-17 and miR-20a in patients with clinical parameters of advanced BC (lymph node metastasis, tumor grade 3, circulating tumor cells, higher Ki-67-related proliferation, hormone receptor negativity and HER2 amplification), when compared to controls. Moreover, decreased level of miR-17 was found from low to high grade. Therefore, miR-17 could represent an indicator of advanced BC. Down-regulated miR-27a expression levels were observed in all clinical categories regardless of tumor progression. Hence, miR-27a could be used as a potential diagnostic marker for BC. Our data indicates that any changes in miRNA expression levels in BC patients in comparison to controls could be highly useful for cancer-associated pathology discrimination. Moreover, dynamics of miRNA expression changes could be used for BC progression monitoring.

Resolvin D1 Modulates the Intracellular VEGF-Related miRNAs of Retinal Photoreceptors Challenged With High Glucose

“…These data are in agreement with a previous report by Nunes et al (2015) which validated the down-regulation of these miRNAs in early diabetes and retinal neovascularization in vivo, together with locally increased VEGF (Nunes et al, 2015). Additionally, miR-20a was predicted to act as a tumor suppressor and was found significantly down-regulated in the serum of advanced breast cancer patients (Jurkovicova et al, 2017). Moreover, miR-20b was able to regulate VEGF expression in a rat model of DR, both in vitro and in vivo (Qin et al, 2016).…”

Prognostic and Clinicopathological Significance of MiR-155 in Breast Cancer: A Systematic Review

“…On the contrary, Wang et al [22] found that serum miR-155 overexpression correlated with ER/PR-negative status. Similar discrepancies were found when other tumour parameters were assessed: Swellam et al [35] and Wang et al [22] found that serum miR-155 correlated with grade, whereas Jurkovicova et al [26] and Anwar et al [37] did not find this correlation. Regarding the TNM stage, five studies [25,27,29,30,35] reported that increased expression of circulating miR-155 was significantly associated with advanced stage, whereas the other four studies [23,30,31,37] did not find any correlations.…”

“…Regarding tumour size, Answar et al [37] assessed the relationship between circulating miR-155 and tumour size, finding a significantly higher miR level in BC patients with tumours larger than 5 cm, whereas Jukovicova et al [26] and Soleimanpour et al [31] found no significant association. Concerning tumour hormonal status, Swellam et al [35] and Jurkovicova et al [26] did not find any significant correlations among serum and plasma miR-155 and ER/PR status, respectively. On the contrary, Wang et al [22] found that serum miR-155 overexpression correlated with ER/PR-negative status.…”

MicroRNA‐17 as a promising diagnostic biomarker of gastric cancer: An investigation combining TCGA, GEO, meta‐analysis, and bioinformatics

“…In patients with recurrent breast cancer, miR-17-5p is upregulated in tumor tissues and significantly downregulated in serum as one of the exosomal miR-NAs [36]. In contrast, statistically significant reductions in the levels of miR-17 and miR-19a in plasma have been observed between early and advanced stages of breast cancer [37]. With regard to the expression of miR-17-5p in GC, the majority of studies considered that this miRNA is upregulated in GC tissues [28][29][30][31][38][39][40].…”