Expression of cancer-testis (CT) antigens in placenta.

Besides their variable presence in fetal and adult germ cells, CT antigens have occasionally been detected in placental tissue. However, these data are scarce and solely based on mRNA analyses; nothing is known about their presence at the protein level. Here, we analyzed the expression of various CT antigens in placental tissues from gestational age week 5 to week 42 using monoclonal antibodies to various antigens of the MAGE-A and -C families, NY-ESO-1, as well as GAGE. We show that CT antigen expression in placenta varies widely for the various antigens, ranging from completely negative to abundant. Since little is known about the function and biology of CT antigens, interpretation of this highly variable expression pattern is purely speculative. However, our data indicate that the various CT antigens have different functions during placental development.