Results of molecular research may improve the management of patients, as well as it is essential to identify powerful prognostic indicator for breast cancer.
It was found that the deregulated miRNAs was correlated with substantial cell physiological and pathological processes and is ultimately involved in tumorigenesis and the tumor progression of many different human cancers. For instance, ectopical expression of miR-148b inhibits the invasion, survival to anoikis, extravasation in breast cancer, and lung metastasis formation of breast cancer cells [
15]. In this study, we investigated the role of miR-124 in breast cancer and the clinicopathological significance and prognostic value of miR-124 in breast cancer. In current study, MiR-124 downregulation was significantly related to advanced clinical stage (stage III and IV) and positive lymph node-metastasis in breast cancer patients. Furthermore, the results showed that lower expression of miR-124 in breast cancer specimens when compared with corresponding adjacent normal breast tissues. These results indicated that miR-124 is downregulated in breast cancer, and decreased expression of miR-124 may be responsible for the progression and metastasis of breast cancer. The miR-124 has been reported that might be involved in epigenetic regulation of various tumors, including breast cancer [
16,
17]. According to the recent studies, down regulated miR-124 can contribute to lymph node-metastasis and tumor progression in patients with breast cancer [
13,
18] and in other cancers patients [
14,
17,
19]. Previous studies have suggested that miR-124 was epigenetically silenced in various types of cancers [
13,
17]. These studies highlighted an important role of miR-124 in the regulation of invasion and metastasis in breast cancer cells, and suggest a potential application of miR-124 in prognosis prediction and cancer treatment. Li et al., [
3] demonstrated that miR-124 might be a tumor suppressor in breast cancer via the regulation of FLOT1. Luciferase assays confirmed that miR- FLOT1 was identified as a direct and functional target of miR-124 that bind to the 3′ untranslated region of FLOT1 and suppress translation. They identified that the FLOT1 gene is as a novel direct target of miR-124, and ectopic expression of miR-124 significantly inhibited FLOT1 [
3]. Han et al. [
13] found that miR-124 was downregulated in breast cancer and the ectopic expression of miR-124could suppress the invasion and metastatic ability, probably by directly targeting the CD151. It is worth noting that these results indicated an important role for miR-124 in the proliferation and metastasis of different cancers [
13].
Kaplan-Meier survival analysis and log-rank test demonstrated that patients with low expression of miR-124 had significantly shorter overall survival than patients who had cancers with high miR-124 expression. Furthermore, multivariate Cox proportional hazards model analysis indicated that low miR-124 expression was independently linked to poor survival of patients with breast cancer and other factors were not significantly associated with survival of patients. Zhang et al. [
20] have shown that decreased expression of miR-148b was linked to poor overall survival of patients with hepatocellular carcinoma, indicating the potential role of miR-148b as a prognostic marker in clinical practice. Furthermore, Zheng et al. showed that miR-124 levels were frequently reduced in hepatocellular carcinoma, and this expression level was significantly associated with the patients’ clinical stages and prognoses, as well as, regulated the invasion and migration of hepatocellular carcinoma [
14]. In addition, Lv et al., Liang et al. and Han et al. also reported that miR-124 can suppress breast cancer growth and metastasis [
13,
18,
21].