Asian Pacifc Journal of Cancer Prevention, Vol 17, 2016 295 DOI:http://dx.doi.org/10.7314/APJCP.2016.17.1.295 Relationship between HER2 Proto-oncogene Status and Prognostic Factors of Breast Cancer in the West of Iran Asian Pac J Cancer Prev, 17 (1), 295-298 Introduction Breast cancer (BC) is the most common health problem in Iranian women that its incidence is increasing rapidly. It is the ffth cause of death and third burden of disease among women malignant disease (Mohammadi et al., 2013). Prognostic factors (well defned and presumptive, anatomic and biochemical, and clinical and molecular) infuence the design, conduct, and analysis of clinical trials of early-stage breast cancer (Dorr, 1993). In addition to, prognostic factors such as age, tumor size, and cancer stage and grade, overexpression of the human epidermal growth factor receptor 2 (HER2)-positive and positivity for estrogen receptor (ER) or progesterone receptor (PR) are heavily studied prognostic (Qin et al., 2015). In BC; ER and PR were the frst predictive molecular markers (Payandeh et al., 2015). However, 25-50% of ER and PR positive tumors are resistant to hormone therapy (Klijin, 1991) , and tumors with HER-2 overexpression do not always respond to trastuzumab therapy. In addition, about 20% of patients with BC are negative for all three markers mentioned above, and their tumors are more resistant to traditional therapy schemes (Yan et al., 2015). However, breast cancers have heterogeneous features 1 Cancer Research Center, 2 Department of Hematology and Medical Oncology, 3 Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran *For correspondence: Sadeghi_mkn@yahoo.com Abstract Background: Breast cancer is a very common health problem in Iranian women. The HER2-neu gene is a transmembrane receptor tyrosine kinase with homology to members of the EGF receptor family. The aim of this study was to investigate the association between HER2-neu oncogene status with prognostic factors of breast cancer in Kermanshah province, Iran. Materials and Methods: Relationship between HER2-neu and prognostic factors of 130 cases of breast cancer were evaluated during two years in Imam Reza hospital in Kermanshah, Iran. Data were analyzed using descriptive statistics and the T-test and Mann-Whitney U non-parametric test using SPSS 19. Results: The mean age for the patients was 46.0±8.0 years, all being female. Among the predictive factors for breast cancer were family history, stage of disease, involvement of the lymphovascular system, number of involved lymph nodes in axillaries, grading and hormone receptor status with HER2-neu oncogene had direct correlation and between factors, tumor location, patient age and histological characteristics and HER2-neu oncogene had no signifcant relationship. We found signifcant correlation between HER2 with ER and PR and also HER2 with ER, PR negative. Conclusions: HER2-neu is risk factor that can be a good prognostic and also predictive factor. For these reasons, we recommend that it be evaluated for all types of BC. Keywords: Breast cancer - HER2 - prognostic factors - trastuzumab RESEARCH ARTICLE Relationship between HER2 Proto-oncogene Status and Prognostic Factors of Breast Cancer in the West of Iran Nasrin Amirifard 1 , Edris Sadeghi 1 *, Mehrdad Payandeh 2 , Hossain Mohebbi 3 , Masoud Sadeghi 3 , Mansour Choubsaz 1 that are diverse in behavior, outcome and response to therapy. It is diffcult to predict outcomes in all breast cancer patients using traditional histopathologic factors and the same biomarkers factors (Dowsett and Dunbier, 2008). In studies suggested a categorization of invasive breast cancers based on genetic profiles into five subtypes with clinical implications: luminal A, luminal B, HER-2/neu overexpressing, normal breast like and triple negative phenotype (Perou et al., 2000; Sotiriou et al., 2003). The HER-2/neu gene encodes a 185-kDa transmembrane receptor tyrosine kinase with homology to members of the EGF receptor family. Unlike the other EGF receptors, HER-2/neu has an intrinsic tyrosine kinase activity that activates receptor-mediated signal transduction in the absence of ligand (Hu et al ., 1992). The immunohistochemical staining for steroid hormone receptors (ER and PR, respectively) and the human epidermal growth factor receptor-2 (HER2) helps to choose appropriate therapies and predict prognosis for breast cancer patients (Doval et al., 2015). A positive HER-2 status in patients with BC correlates with high sensitivity to targeted therapy with trastuzumab. These biomarkers play an important role in clinical practice by individualizing treatment and determining adequate