PTEN promoter methylation and protein expression in normal early placentas and hydatidiform moles

To investigate the relationship between PTEN promoter methylation and protein expression, and the possible involvement of the PTEN gene in development of gestational trophoblasts and the pathogenesis of hydatidiform moles.

DNA was extracted from choria of normal early placentas, partial hydatidiform moles, complete hydatidiform moles, and invasive moles, and overdigested by methylation-sensitive endonuclease HpaII. The PTEN promoter was amplificated by polymerase chain reaction. PTEN protein expression was detected by immunohistochemistry.

In partial and complete hydatidiform moles, the PTEN promoter methylation rate was significantly higher than in early placentas (72%, 59.4%, 14.3%; P = .000, .002, respectively), and the PTEN protein expression rate was significantly lower than in early placentas (9.1%, 4.5%, 90.5%; P = .000, .000, respectively). However, partial hydatidiform moles, complete hydatidiform moles, and invasive moles were not significant different in terms of PTEN promoter methylation and protein expression.

These findings suggest that the regulation of PTEN expression may play an important role in the development of the early gestational trophoblast and in the pathogenesis of hydatidiform mole, but not in its malignant transformation.