Pathogenic role of Twist-1 protein in hydatidiform molar pregnancies and investigation of its potential diagnostic utility in complete moles.

Background: Complete and partial moles (PM) are the most common gestational trophoblastic diseases. Due to some overlapping morphological findings, ancillary studies may be necessary.

Methods: In this cross-sectional study, 47 cases of complete mole (CM) and 40 cases of PM were randomly selected based on histopathological criteria. Only those cases that were agreed upon by two expert gynecological pathologists and confirmed by the P57 IHC study were included. The expression level of the Twist-1 marker in villi stromal cells, as well as syncytiotrophoblasts, was evaluated quantitatively (percentage of positive cells), qualitatively (staining intensity) and as a total comprehensive score.

Results: Expression of Twist-1 is higher and more intense in villous stromal cells of CMs (p < 0.001). Moderate to strong staining intensity in more than 50% of villous stromal cells, can differentiate CM and PM with 89.5% sensitivity and 75% specificity. In syncytiotrophoblasts of CM, Twist-1 expression was significantly lower than PM (p < 0.001). Negative or weak staining intensity in less than 10% of syncytiotrophoblasts, can distinguish CM and PM with 82.9% sensitivity and 60% specificity.

Conclusion: A higher expression of Twist-1 in villous stromal cells of hydatidiform moles is a sensitive and specific marker for the diagnosis of CMs. An elevated expression of this marker in villous stromal cells suggests another pathogenic mechanism for more aggressiveness of CMs in addition to the characteristics of trophoblast cells. The opposite result was obtained in the expression of Twist-1 in the syncytiotrophoblasts, compatible with defects in the process of formation of these supportive cells in CMs.