ERBB2 and neoplasm: The phenotypic characterization of our three novel GEMMs proves that GSDMB2 pro-tumor function is dependent on the biological context: GSDMB2 alone does not have strong in vivo spontaneous oncogenic properties (though a potential reduction of gastric tumorigenesis requires future studies), while in the mammary gland, it fuels carcinogenesis in concert with the HER2, and not PyMT, oncogene.