_____________________________________________________________________________________________________ *Corresponding author: Email: belhadj_ami@yahoo.fr; Original Research Article Journal of International Research in Medical and Pharmaceutical Sciences 6(1): 18-24, 2016 ISSN: 2395-4477 (P), ISSN: 2395-4485 (O) International Knowledge Press www.ikpress.org EPIDEMIOLOGICAL STUDY AND MOLECULAR BREAST CANCER SUBTYPES DISTRIBUTION AMONG WEST ALGERIAN PATIENTS AMINA BELHADJ 1* , LYNDA ADDOU-KLOUCHE 1 , MERIEM KAOUTER BENYELLES 1 , AMINA BENDAOUD 1 , IKRAM ZIANE 1 , BADRA ZAKMOUT 1 , ISSAM BOUAKLINE 2 , MILOUD MEDJAMIA 2 , HAMID JELLOUL BENAMMAR 3 , SOFIANE BOUAZZA 1 , ZOHEIR DAHMANI 4 , MOHAMED BENALI 1 AND SORAYA MOULESSEHOUL 1 1 Department of Biology, Biotoxicology Laboratory, University Djillali Liabes, BP 89 Avenue Larbi Ben Mehidi, Sidi Bel Abbes 22000, Algeria. 2 Anatomy and Pathology Laboratory, Regional Military Hospital University, Oran, 31000, Algeria. 3 Anatomy and Pathology Laboratory, University Hospital, Sidi Bel Abbes 22000, Algeria. 4 Laboratory of Applied Molecular Biology and Immunology, University Abou Bakr Seddik, Tlemcen 13000, Algeria. AUTHORS’ CONTRIBUTIONS This work was carried out in collaboration between all authors. Authors IB, MM and HJB designed the study, wrote the protocol and interpreted the data. Authors SB and ZD anchored the field study, gathered the initial data and performed preliminary data analysis. While authors AMINA BELHADJ, LAK, MKB, AMINA BENDAOUD, IZ and BZ managed the literature searches. Authors AMINA BELHADJ and LAK managed the literature searches and produced the initial draft. All authors read and approved the final manuscript. Received: 11 th August 2015 Accepted: 31 st August 2015 Published: 14 th September 2015 __________________________________________________________________________________ ABSTRACT Purpose: Breast cancer is the leading cause of cancer death in women worldwide and in particular in Algeria. Breast cancer is a heterogenous disease; its molecular classification is based on gene expression and on proteomic profile to distinguish five major subtypes: luminal A, Luminal B, HER2+, basal like and normal like. We aimed in present study to achieve an epidemiologic study and to correlate molecular breast cancer subtypes with clinico pathological features among west Algerian patients. Materials and Methods: We performed a retrospective study on 829 patients diagnosed with primary breast cancer who underwent initial surgery in west Algeria Hospitals between january 2008 and December 2013. Assessment of estrogen/progesterone receptors and HER2 protein expression on some cases was determined by immunohistochemistry. Molecular subtypes definitions were as follows: Luminal A (ER+, PR+/-, HER2-), luminal B ( ER+, PR+/-, HER2+), Triple negative (ER-, PR-, HER2-), HER2+( ER-, PR-, HER+), they were correlated with some clinical characteristics: median age, histological type, SBR grade and pathological axillary lymph node status. Results: The mean and median age of the 829 patients were 50.66 and 49 years respectively. 62% of the patients had positive lymph nodes and 11% had distant metastasis at diagnosis. Metastasis free survival at 5