Abstract 3945: PTEN loss is associated with aggressive behavior and poor prognosis in Middle Eastern Triple Negative Breast Cancer

Abstract

Abstract PTEN is a tumor suppressor that negatively regulates the PI3K-AKT signaling pathway which is involved in the pathogenesis of many different tumor types and serves as a prognostic marker in breast cancer. However, the significance of the role of PTEN in Middle Eastern ethnic breast cancer has not been explored especially with the fact that breast cancer originating from this ethnic population tend to behave more aggressively than breast cancer in the west. In order to learn more on the prevalence and clinical significance of PTEN protein expression and PTEN gene deletions, a tissue microarray containing more than 1000 primary breast cancers with clinical follow up data was used. Tissue Microarray sections were analyzed for protein expression and copy number change using immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). Loss of PTEN immunostaining was observed in 77% of the cases. PTEN loss was significantly associated with large tumor size (p = 0.0030), high grade (p = 0.0281), tumor recurrence (p = 0.0333) and Triple negative breast cancers (p = 0.0086). PTEN loss in Triple negative breast cancers was significantly associated with rapid tumor cell proliferation (p = 0.0396) and poor prognosis (p = 0.0408). PTEN deletion was found only in 60 cases (6.4%) of cases. It was concluded that loss of PTEN protein expression occurs at high frequency in Middle Eastern breast cancer. PTEN inactivation may potentially lead to an aggressive behavior of tumor cells through stimulation of tumor cell proliferation. Furthermore PTEN signaling pathway might be used as potential therapeutic target in Triple negative breast cancers since loss of its expression is shown to be significantly associated with this aggressive subtype of breast cancer. Citation Format: Abdul K. Siraj, Shaham Beg, Sarita Prabhakaran, Zeenath Jehan, Dahish Ajarim, Fouad Al-Dayel, Asma Tulbah, Khawla Al-Kuraya. PTEN loss is associated with aggressive behavior and poor prognosis in Middle Eastern Triple Negative Breast Cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3945. doi:10.1158/1538-7445.AM2015-3945