Abstract 1482: Caveolin is related to progression of malignant transformation in patients with breast tumors.

Abstract Aim: Caveolin seems to be an important factor in tumorigenesis and progression. It has a dual role in both tumor suppression and progression. The proponents of tumor suppression suggest that caveolin is the major protein of the cavea in the cells and these regions accumulate the growth stimulatory signals from certain growth factors such as epidermal growth factor family. Locus of caveolin gene on chromosome 7 is closely related to other tumor suppressor genes. Proponents of the oncogenic role state that caveolin is highly expressed in cancer tissues such as prostate, lung, and renal cell carcinoma when compared to normal counterparts. This type of expression in breast cancers has been ill defined in previous studies. We designed a detailed study in order to evaluate the expression of caveolin in breast cancers and investigation of its possible use as target of specific cancer therapy. The initial phase of the study consists of evaluation of caveolin in patients with benign and malignant breast disease with respect to normal controls. Here we present our preliminary results of the first phase of the study. Materials and methods: Breast tissue from 202 benign breast tumors, 98 breast cancers and 20 normal controls (obtained from reduction mammoplasties with informed consent) in our center. Caveolin was evaluated by immunohistochemistry. Results: Caveolin distribution was higher in malignant tissues when compared to control tissues and benign tumors. Furthermore caveolin antigen distribution was enhanced with more aggressive tumor behavior. We observed enhanced caveolin expression especially in myoepithelial cells. The benign tumors expressed higher caveolin when compared to normal controls. In both benign and malignant breast tumors the caveolin expression increased with stromal content of the tumor. Conclusion: Tumor microenvironment influences the tumor tissue interms of proliferation and metastasis. Caveolin seems to be expressed in the stromal component of the tumor and seems to have increased expression with aggressive nature of the tumor. Results of this preliminary study suggests that caveolin plays a determinative role in tumorigenesis in breast cancer and furthermore correlates with the aggressiveness of the tumor. Caveolin may exert its oncogenic effects by promoting epithelial to mesenchymal transition. Therefore targeting caveolin may be logical strategy in breast cancer treatment. Citation Format: Hasan Bostanci, Tevfik Tolga Sahin, Kursat Dikmen, Aynur Albayrak, Volkan Yildirim, Hulagu Kargici. Caveolin is related to progression of malignant transformation in patients with breast tumors. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1482. doi:10.1158/1538-7445.AM2013-1482