fetal-placental protein and an underappreciated therapeutic target in cancer

Placenta-specific protein 1 (PLAC1) is an X-linked gene whose expression is almost exclusively limited to placental trophoblasts. Its expression profile and evolutionary history suggest that it is important in the proper establishment and maintenance of a healthy placenta and a successful gestation throughout the Eutheria through promoting invasiveness, migration and proliferation of placental tissue. For the same reasons, PLAC1 expression has been found to be co-opted in a variety of cancers. For reasons less understood, it is also expressed in developing embryos. Thus, PLAC1 is the only known member of a class of proteins termed “onco-fetal-placental.”