PIK3CA and carcinoma: Consistent with the notion that ER-negative adenomyoepitheliomas may constitute the breast counterpart of epithelial−myoepithelial carcinomas of the salivary glands, up to 80% of salivary gland epithelial−myoepithelial carcinomas have been reported to harbor HRAS Q61 hotspot mutations40,41, which are reported to co-occur with PIK3CA mutations in approximately 40% of cases40.