Abstract
About 5 % of odontogenic keratocysts (OKC) arise in association with basal cell nevus syndrome (BCNS), a genetical disorder caused by aberrant function of patched1 (ptch1) gene. Ptch1 is a receptor of Sonic hedgehog (Shh), whose signaling plays a role in proliferation of developing odontogenic epithelium. OKC specimens from five BCNS patients were examined immunohistochemically for expression of Ptch1, Ptch2, Shh and CyclinD1. Ptch1 and Shh staining was distinct in the lining epithelium, and 20-50 % of basal/suprabasal cells were positive for CyclinD1. Ptch2 staining was as weak as none. Loss of heterozygosity (LOH) in ptch1 and ptch2 loci was probed; in which one case showed no LOH for ptch1 while three cases showed no LOH for ptch2. Co-expression of Shh and its receptor in OKC epithelium implicates that autocrine or paracrine activation of hedgehog signaling within the lining cells is involved in genesis of OKC associated with BCNS.
