Hossein Javid - Department of Clinical Biochemistry, School of Medicine, Mashhad University of Medical Sciences, Mashhad, IRAN
Seyyed Isaac Hashemy - Department of Clinical Biochemistry, School of Medicine, Mashhad University of Medical Sciences, Mashhad, IRAN
Soudabeh shahidsales - Department of Oncology, Omid Hospital, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
Nema Mohammadian Roshan - Department of Pathology, Ghaem Hospital, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran

Background &Aim: Breast cancer is the most common cancer among women in the world. Prohibitin (PHB) is a homologous protein which binds to P53 protein and enhances its transcriptional activity. It has been also reported that PHB1 may act as an anchor in the cell membrane for C-Raf. The aim of this study was to measure the level of PHB1 in serum of patients with breast cancer. Methods: Blood samples were taken from 78 patients who had referred to Omid University-Hospital in Mashhad and were willing to participate in the study. After obtaining informed consent, the serum level of prohibitin was measured in collected sera by ELISA method using Kazabayo Company research kit according to the protocol provided. The relationship between the serum level of PHB1 and other known prognostic factors of breast cancer was investigated Results: Prohibitin level in serum of patients was reported with a median of 1.03 ng/ml. A slight increase in the level of PHB1 was seen with higher tumoral grade, and also in people with positive ER (estrogen receptor) and PR (progesterone receptor) compared to people with negative hormone receptors; but no significant correlation with these factors neither other factors (including HER2) was detected. Conclusion: Our study did not show any significant correlation between serumic level of PHB1 and tumor stage; though, in previous reports tissue distribution of prohibitin have shown a good correlation with prognostic factors in breast cancer using immunohistochemistry technique. This might be due to insufficient level of PHB in the blood

breast cancer; prohibitin; ELISA