Studies on Basal Cell Carcinoma: Role of Human Homologue of Drosophila Patched Gene

This thesis investigated the biological and genetic factors involved in basal cell carcinoma (BCC), the most common cancer in the Western world. It highlighted the role of stromelysin 3 (ST3) in the invasiveness and fibrosis development of BCCs. The study localized the Nevoid Basal Cell Carcinoma Syndrome (NBCCS) gene to chromosome 9q22.3 and identified the human homologue of the Drosophila patched gene (PTCH) as the NBCCS gene. PTCH mutations were found in both hereditary and sporadic BCCs, often resulting in truncated proteins. PTCH mRNA was consistently overexpressed in BCCs and trichoepitheliomas, suggesting a common pathogenic pathway for these skin tumors. The findings supported a gatekeeper mechanism in skin tumorigenesis involving alterations in the PTCH signaling pathway.