Progesterone receptor membrane component 1 (PGRMC1) is a member of a multi-protein progesterone-binding complex. However,PGRMC1 shares homology with cytochrome b5-related proteins rather than hormone receptors . It is a heme binding protein with biding sites for Src homology (SH2) and SH3 domain-containing proteins . PGRMC1 is overexpressed in a variety of cancers,and thus represents an important biomarker for cancer progression and a potential target for anticancer drugs . In nonmalignant tissues,PGRMC1 is highly expressed in the liver and kidney .