The Patched gene is epigenetically regulated in ovarian dermoids and fibromas, but not in basocellular carcinomas

The Hedgehog/Patched signaling pathway plays a prominent role during mammalian development but it is also involved in oncogenic transformation. We investigated the methylation status of the Patched promotor in a set of basocellular carcinomas of the skin and ovarian tumors as an alternative to mutational causes of the pathway deregulation. Our aim was to define a possible role of genetic and/or epigenetic mechanisms of Hedgehog/Patched signal transduction in the development of these tumors. Bisulfite-converted DNA from tumors and from matched healthy tissue was amplified by a specific PCR and the CpG-rich regions of the Patched promoter were sequenced. Two promoter regions showed statistically significant hypermethylation compared to healthy controls in ovarian tumors; more significantly in the region in the vicinity of Gli1-binding sites and less significantly in the region containing the ATG codon. But, in basocellular carcinomas of the skin we observed no difference in methylation, suggesting different mechanisms of neoplasia in these tumors.