ISSN 2320-5407 International Journal of Advanced Research (2015), Volume 3, Issue 1, 296-306 296 Journal homepage: http://www.journalijar.com INTERNATIONAL JOURNAL OF ADVANCED RESEARCH RESEARCH ARTICLE Role of ERG, PTEN and KI67 Proteins Expression in Prognosis of Metastatic Prostate Cancer Eman H. Abdelbary 1 , Abdelmonem A. Hegazy 2 , Mohamed Abdelgawad 3 , and Ragab A. Ahmed 4 1. Pathology Department, Zagazig University, Egypt. 2. Anatomy and Embryology Department, Zagazig University, Egypt. 3. Clinical Oncology and Nuclear Medicine Department, Zagazig University, Egypt. 4. Urology Department, Faculty of Medicine, Zagazig University, Egypt. Manuscript Info Abstract Manuscript History: Received: 12 November 2014 Final Accepted: 26 December 2014 Published Online: January 2015 Key words: ERG, PTEN, KI67, Immunohistochemistry, Metastatic prostate cancer, Prognosis *Corresponding Author Eman H. Abdelbary Background: Prostate cancer is a leading cause of cancer-related mortality in men. Despite improvements in early detection of prostate cancer as a result of PSA screening, we still lack molecular markers to effectively distinguish patients with high risk of disease progression from the indolent majority. Aim of the work: To assess the prognostic value of ERG, PTEN and KI67 proteins expression in metastatic prostate cancer patients, as well as their relationship to clinicopathologic features of the disease. Patients and Methods: ERG, PTEN and KI67 proteins expression was assessed immunohistochemically in series of metastatic prostate cancers and their prognostic significance was evaluated. Results: High ERG score as well as high KI67 labeling index (LI) were strongly associated (P <0.001) with high pre-treatment PSA level, Gleason score ޓ7, advanced tumor stage, metastasis affecting both bone & lymph nodes and biochemical progression. PTEN loss was significantly associated with high pre-treatment PSA level (P ޒ0.001), Gleason score ޓ7 (P =0.002), advanced tumor stage (P =0.015), metastasis affecting both bone & lymph nodes (P =0.002) and biochemical progression (P =0.001). A significant association was found between higher KI67 LI (P ޒ0.001), higher ERG expression score (P =0.005) & PTEN loss (P =0.007) and shorter progression free survival. ERG expression and PTEN loss were significantly associated with KI67 LI (P =0.011 & 0.0.013 respectively), however, no relationship could be proved between both of them (P =0.256). ERG (P =0.025) was the only independent predictor for biochemical progression in multivariate analysis. Conclusions: ERG and KI67 expressions and PTEN loss have an important prognostic value in metastatic prostate cancer. Using them to differentiate between patients who are at a high or low risk of disease progression may help to identify patients who will benefit the most from treatment. Copy Right, IJAR, 2015,. All rights reserved INTRODUCTION Prostate cancer (PC) is a leading cause of cancer-related mortality in men. More than 600,000 men are annually diagnosed as having prostate cancer worldwide (1). In spite of the improvements in early detection of