DOC-2/hDab2, a candidate tumor suppressor gene involved in the development of gestational trophoblastic diseases.

Gestational trophoblastic diseases comprise a spectrum of interrelated diseases including partial mole, complete mole and gestational choriocarcinoma. Using reverse transcriptase PCR (RT-PCR) analysis, we identified higher levels of DOC-2/hDab2 expression in the normal trophoblast cells in culture than in choriocarcinoma cell lines. Subsequent study using immunohistochemistry showed high levels of DOC-2/hDab2 protein expression in normal trophoblast tissues but significantly lower levels of expression in gestational trophoblastic disease tissues, particularly in complete mole and choriocarcinoma. When DOC-2/hDab2 was transfected into the choriocarcinoma cell lines, Jar, JEG and BeWo, the stable transfectants showed significantly reduced growth rate in culture. These data suggest that down regulation of DOC-2/hDab2 may play an important role in the development of gestational trophoblastic diseases.