When compared with tissue sections of human Luminal A and HER2 + breast cancers, immunohistochemical analysis of breast ductal adenocarcinomas from Rosa26-RRAS2fl/fl x Wap-Cre mice revealed the lack of ERα, PR, and ErbB2 markers, (Fig. 1c). The gene discussed is PGR; the disease is breast ductal adenocarcinoma.