Diagnostic value of P63 in differentiating normal gestation from molar pregnancy

Considering the limitations of current pathologic methods in distinguishing two subtypes of hydatidiform mole and non-molar pregnancy, the utility of immunohistochemical markers in this regards and the importance of differentiating of mentioned pathologic patterns, in this study the expression of P63 in patients with complete hydatidiform mole (CHM), partial hydatidiform mole (PHM) and non-molar pregnancy was determined.

In this study, formalin-fixed and paraffin-embedded tissues of 61 patients with definitive pathologic diagnosis of CHM, PHM and non-molar pregnancy retrieved. Diagnoses were based on the study of hematoxylin and eosin stained slides. Sections from all samples were stained for P63 marker using immunohistochemistry method. The nuclear immune reactivity of P63 marker in the three pathologic groups was determined by two pathologists.

P63 immune-staining was used to evaluate 20, 26 and 15 non-molar pregnancy, CHM and PHM cases, respectively. Mean ± SD of P63 nuclear immune-staining in molar pregnancy (CHM and PHM) and non-molar pregnancy were 32.4 ± 17.4 and 18.9 ± 17.2, respectively (P = 0.006). The means were significantly different between non-molar pregnancy and PHM (P < 0.000), CHM and PHM (P = 0.02) and non-molar pregnancy and CHM (P = 0.04).

Considering the findings of the current study, though the nuclear immunoreactivity of P63 was higher in molar than non-molar pregnancy and in PHM than CHM, but using this marker alone is not suitable as a diagnostic test due to its low sensitivity and specificity. It could be used as adjuvant test in conflict cases. It is recommended to evaluate the role of other immunohistochemical markers like Ki-67 in this regard.