Assessment of Her-2/neu expression in hydatidiform moles for prediction of subsequent gestational trophoblastic neoplasia.

OBJECTIVE

The aim of the present study was to asses the ability of Her-2/neu immunohistochemical staining of the molar tissue to predict the risk of developing gestational trophoblastic neoplasia (GTN).

METHODS

Sections prepared from 33 consecutive formalin-fixed paraffin-embedded archival reconfirmed hydatidiform mole tissue blocks were immunohistochemically stained for Her-2/neu. The staining was scored according to the subjectively evaluated intensity of staining and the proportion of stained villous cytotrophoblastic cells. Clinical data were abstracted from medical files.

RESULTS

23 patients had a complete and 10 a partial mole. Nine patients (27.3%) were diagnosed with GTN [7 of 23 patients with a complete mole (30.4%) and 2 of the 10 (20.0%) with a partial mole]. A positive immunohistochemical Her-2/neu stain was found in 6 (18.2%) of the patients with hydatidiform mole (3 with a complete mole). The rate of Her-2/neu expression was somewhat higher in moles with subsequent GTN than in moles with an uneventful course (22.2% vs. 16.6%, respectively). The difference did not reach significance (Fisher's Exact Test, P=0.55) possibly due to the small number of cases (power of <5%). The sensitivity and specificity of Her-2/neu expression for prediction of GTN was 22.2% and 83.3%, respectively, and the positive and negative predictive value 33.3% and 74.1%, respectively.

CONCLUSION

While the specificity of Her-2/neu immunohistochemical staining for prediction of GTN is relatively high, the low sensitivity and low positive and negative predictive value precludes its practical clinical use for prediction of post-molar GTN. The quest for a precise predictor of post-molar GTN should continue.