Consistent with the GSDMB pro-tumor functions in human HER2 carcinomas, our two novel breast cancer models (R26-GB2/MMTV-NEU and R26-GB2/MMTV-PyMT) proved that GSDMB2 expression significantly augments breast cancer formation only in the context of HER2-driven tumorigenesis. This evidence concerns the gene ERBB2 and breast cancer.