Using miR-125b in the Prediction of Aromatase Inhibitors Resistance in Metastatic Breast Cancer

Background: Several studies investigated the miRNAs in cancer trying to assess the prognosis or to predict the response to certain treatment .One of these miRNAs are miR 125b , it was suggested by previous results as a good marker for prediction of aromatase inhibitors (AI) response. So, this study was conducted to assess the value using miRNA125b as a predictive factor to AI response. Patients and Methods: A total of 90 patients of postmenopausal HR+ve metastatic breast cancer who attended to medical oncology department outpatient’s clinic in SECI, Assiut university Egypt, from May 2017 to September 2018. Patients presented with metastasis at diagnosis as well as patients who relapsed only after 3 years of adjuvant hormonal treatment with SERM were included. All patients received AI as first line treatment for metastatic, miRNA 125b was isolated from peripheral blood samples and measured by using (q PCR).The response of patients was assessed by RECIST criteria and correlated with its expression levels. Results: Expression of the miR125-b was significantly higher in patients than control p= 0.000. However, no significant difference in its expression between those with single of multiple metastases or even between the site of metastases. We didn’t find also any significant difference in response p=0.648 and survival either PFS p=0.406 or OS p=0.384 between those patients with high expression vs. low expression. Conclusion: Our results suggest that miR125b could be used as a diagnostic marker as it is significantly increased in patients than control. However, we don’t recommend using miR125b as a marker to predict the AI resistance as further studies with large sample size are needed to confirm these results.