European Scientific Journal October 2016 edition vol.12, No.30 ISSN: 1857 – 7881 (Print) e - ISSN 1857- 7431 378 Flow Cytometry of Breast Cancer Resistant Protein and microRNA in Breast Cancer Patients Post Metformin Effect Bassent Gamal Abdel Nasser Mohammed (MSc) Ashour Abdel Salam Abdel Mawla (Professor) Department of Histochemistry and Cell biology medical research institute, Alexandria University Sameh Ibrahim Zaki (Professor) Department of Cancer research and management medical research institute Alexandria University Mohamed Atteya Saad Atteya (Assistant professor) Department of Clinical pathology, Faculty of medicine, Tanta University 378 p 30 URL:http://dx.doi.org/10.19044/esj.2016.v12n 378 p 30 doi: 10.19044/esj.2016.v12n Abstract The goal of the present study is to investigate the role of metformin (MF) as a target of miRNAs in breast cancer resistant protein (BCRP) inhibition in an attempt to develop treatment strategies that may improve the response of breast cancer (BC) patients to chemotherapy (CT). In order to fulfill this target, non-diabetic female subjects were categorized into three groups: control group (group 1) (n=5), CT group of BC patients (group 2) (n=25) and CT plus MF group of BC patients (group 3) (n=25). All patients were subjected to full history taking, laboratory studies including mammogram, chest X-ray, pelvic-abdominal ultrasound and isotopic bone scan, in addition to ER and PR states. CT group was treated with neoadjuvent CT in the form of 5-FU (500 mg/m 2 ), Adriamycin (50 mg/m 2 ) and cyclophosphamide (500 mg/m 2 ). Flow cytometry (FC) of BCRP and MiRNA was carried out on blood samples at every cycle of treatment for all partners. The results showed the presence of miRNA was higher than the presence of BCRP in the normal healthy control group. In most cases of CT and CT plus MF groups (group 2, 3) it was well noticed that the amount of BCRP in the blood samples exceeded that of miRNA illustrated the dysregulation of miRNA in BC patients and also to prove the basic role of BCRP as a multidrug resistance (MDR) for chemotherapeutic agents in patients with BC.