Abstract B022: The adaptor protein FRS2beta fashions a cytokine-rich inflammatory microenvironment that is associated with DCIS and promotes breast cancer carcinogenesis

Abstract

Abstract Although it is commonly held that pro-inflammatory changes precede the onset of breast cancer, the underlying mechanisms remain obscure. Here, we report that FRS2beta, an adaptor protein with a highly restricted epithelial expression pattern, mediates the pro-inflammatory changes that alter the stroma in premalignant mammary tissues. We posit that these changes, which include lesions of ductal carcinoma in situ (DCIS), precede disease onset. In the MMTV-ErbB2 mouse model of mammary carcinoma, FRS2beta-deficiency markedly attenuated tumorigenesis. Importantly, tumor cells derived from MMTV-ErbB2 mice failed to generate tumors when grafted in the FRS2beta-deficient premalignant tissues. We found that the co-localization of FRS2beta and the NEMO subunit of the IkappaB kinase (IKK) complex in early endosomes activated nuclear factor-kappaB (NFkappaB), a master regulator of inflammation. Moreover, the inhibition of NFkappaB-induced cytokines CXC chemokine ligand (CXCL)12 and insulin-like growth factor (IGF1) abrogated tumorigenesis. In line with this, human breast cancer tissues that express higher levels of FRS2beta contain more stroma. The elucidation of the FRS2beta-NFkappaB axis uncovers a hitherto unknown molecular link between the pro-inflammatory changes in the DCIS and the disease onset. Citation Format: Noriko Gotoh. The adaptor protein FRS2beta fashions a cytokine-rich inflammatory microenvironment that is associated with DCIS and promotes breast cancer carcinogenesis [abstract]. In: Proceedings of the AACR Special Conference on Rethinking DCIS: An Opportunity for Prevention?; 2022 Sep 8-11; Philadelphia, PA. Philadelphia (PA): AACR; Can Prev Res 2022;15(12 Suppl_1): Abstract nr B022.