Description
We report a mouse model that recapitulates expression of the ETV6-NTRK3 (EN) fusion oncoprotein, the product of the t(12;15)(p13;q25) translocation characteristic of human secretory breast carcinoma. Activation of EN expression in mammary tissues by Whey acidic protein (Wap) promoter-driven Cre leads to fully penetrant, multifocal malignant breast cancer with short latency. We provide genetic evidence that committed bipotent or CD61+ luminal alveolar progenitors, are targets of tumorigenesis. Furthermore, EN transforms these otherwise transient progenitors through activation of the AP1 complex.