PGRMC1 and breast neoplasm: Accordingly, Lee and collaborators [156] used a transgenic mouse model that spontaneously developed breast tumors, which were in turn backcrossed with Pgrmc1 knockout (KO) mice to demonstrate that the tumors that developed in the Pgrmc1 KO mice had a lower metastatic ability and a lower expression of focal adhesion kinase (FAK) [156].