The Expression Levels of Circulating miR-129 and miR-203a in Association with Breast Cancer and Related Metastasis

Background: a significant part of deaths related to breast cancer is the result of invasion to other organs. it is essential to discover new non-invasive biomarkers to improve anticipation of recurrence risk in breast cancer patients. in this study, the plasma levels of mir-129 and mir-203a were evaluated to investigate their diagnos-tic potential in breast cancer and its metastasis.methods: in this case-control study, conducted in tarbiat modares university, tehran, iran, in 2019, invasive ductal carcinoma blood samples were divided into 3 groups based on their stages as i, ii/iii, iv. each group contained 30 individuals. we also recruited 30 normal individuals as a control group. real-time pcr was con-ducted to evaluate mir-129 and mir-203a expression levels. the discriminatory ability of the evaluated plasma mirnas was assessed by roc (receiver operating characteristic) curves in breast cancer diagnosis and its metastasis.results: mir-129 and mir-203a expression levels were significantly downregulated in breast cancer. reducing tendency was observed in the mentioned mirnas from less to more invasive stages. the expression level of mir-129 was decreased in metastatic than non-metastatic patients and it was significantly related to metastasis. a significant association between mir-129 expression level and lymph node status was also observed (p=0.04). evaluation of roc curves revealed that mir-129 and mir-203a were able to discriminate breast cancer fairly and poorly respectively. the ability of mir-129 in the diagnosis of breast cancer metastasis was poor.conclusion: mir-129 and mir-203a may both act as tumor suppressor mirnas. our results need further evidence in a large population to be confirmed as diagnostic markers.