CDKN1C and choriocarcinoma: Cases with no prior clinical history and a morphological diagnosis of a molar pregnancy would be better suited to initial screening by p57 staining and FISH ploidy testing, with atypical cases followed up by parent-of-origin testing to establish whether uniparental disomy has occurred, and also methylation analysis of the p57 gene to assess the risk of choriocarcinoma development.