Expression of Pik3ca-mutations in luminal cells (e.g., using promoters MMTV, WAP and Krt8) mostly evoked adenosquamous mammary carcinomas, which exhibited mixed-lineage features highlighted by the presence of KRT14/KRT8 & KRT18 double-positive cancer cells [6, 65–67]. Here, KRT8 is linked to breast carcinoma.