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

Abstract

IntroductionMicroRNAs are small, non coding regulatory molecules containing approximately 21 to 25 nucleotides. They function as controllers of expression at post transcriptional levels of most human protein-coding genes and play an essential role in cell signaling pathways. The objective of the present study is to evaluate the expression profile of the following micro-RNAs: miR-10b, miR-17, miR-21, miR-34a, miR-146a, miR-148a and miR-182, and to determine their possible interaction in triple-negative and non triple-negative primary breast cancers based on clinical outcome.Methods60 triple-negative and non triple-negative breast cancer cases, along with their corresponding normal samples were investigated in relation to the expression of the seven studied miRNAs using qPCR Syber Green.ResultsWe observed that miR-21, miR-146a and miR-182 were significantly over expressed in triple negative breast cancer. Moreover, miR-10b, miR-21 and miR-182 were significantly associated to lymph node metastases occurrence in triple negative breast carcinoma while only miR-10b was associated with grade III in non triple negative breast cancer cases. Almost all the analyzed microRNAs were strongly associated with patients’ genico-obstetric history in non triple negative breast cancer cases except for miR-34a. All the studied microRNAs were strongly correlated with the use of the contraceptive pills in non triple negative breast cancer groups. The additive effect of hormonal factors in triple negative breast cancer cases showed an association with all the studied miRs except for miR-34 and miR-146a.ConclusionThe studied microRNAs are strongly influenced by environmental factors especially with hormonal patients’ history. Moreover, miR-10b, miR-21 and miR-182 could be defined as biomarkers in breast cancer to predict both lymph node metastases and grade III occurrence.

Dysregulation of microRNAs in triple-negative breast cancer

“…Therefore, tumor cells do not activate the apoptotic pathway and become more resistant to treatment [23]. Medimegh et al have noticed a significant association of lymph node metastases with miR-182 overexpression in TNBC of Tunisian population [19]. In present study we did not find any significant association between miR-182-5p expression and lymph node status, which is consistent with results of Krishnan et al (2013) [24].…”

“…The analysis showed significantly higher expression of miR-182 in TNBC with respect to NTNBC cases. Moreover, the expression of miR-182 in both cancer groups was still higher than in healthy controls [19]. In present study we confirm the increased expression of miR-182-5p in TNBC patients.…”

“…Medimegh et al (2014) examined expression of miR-182 in the following three groups: TNBC, NTNBC (Non Triple Negative Breast Cancer; Luminal A, Luminal B and HER2 positive patients) and healthy controls. The analysis showed significantly higher expression of miR-182 in TNBC with respect to NTNBC cases.…”

Recent Progress in Triple Negative Breast Cancer Research

“…In the non-TNBC groups studied, micro-RNAs have highly been correlated to the use of contraceptive pills, and excepted miR-34 and miR-146a, the addition of hormonal factors have showed an association with the miRs in the case of TNBC (Medimegh et al, 2014).…”

“…Recently, Medimegh et al have explored the expression level of seven micro-RNAs: miR10b, miR-17, miR-21, miR-34a, miR-146a, miR-148a and miR-182 in both TNBC and non TNBC cases, and have showed that (Medimegh et al, 2014): miR-21, miR-146a and miR-182 are significantly expressed in TNBC. miR-10b, miR-21 and miR-182 are significantly associated with lymph node metastasis occurrence in TNBC.…”