A comparison between D2-40 and c-KIT immunohistochemistry for the human fetal testis and ovary at the second trimester of gestation

Abstract

Both M2A (D2-40) and c-KIT have frequently been used as markers of germ cell tumors. However, comparative studies of their immunoreactivities in human fetal gonads have been limited. Using horizontal semiserial whole-abdomen sections of 9 human abortuses at 12 weeks (2 males and 1 females; CRL 70-80 mm), 15 weeks (2 males and 3 females; 115-125 mm) and 18 weeks (1 female; 155 mm) of gestation, we identified germ cells in the testis and ovary on the basis of c-KIT immunoreactivity. M2A was also stained using near or adjacent sections. In 12-week fetuses, c-KIT immunoreactivity was weak, but M2A immunoreactivity was consistently strong. At 15 and 18 weeks of gestation, c-KIT immunoreactivity was found in most germ cells. M2A was expressed in Sertoli cells as well as in germ cells, but was not expressed in ovarian follicles undergoing meiosis. M2A appears to be a more useful marker of germ cells than c-KIT in human fetal testis and ovary at the second trimester. M2A is also reactive in fetal Sertoli cells, but its expression is consistently weaker than in germ cells.