Transgenic mice overexpressing protein kinase C epsilon in their epidermis exhibit reduced papilloma burden but enhanced carcinoma formation after tumor promotion.

The study investigated the role of protein kinase C epsilon (PKCepsilon) in skin growth and tumor promotion using transgenic mice overexpressing PKCepsilon in their epidermis. Three independent mouse lines were created, with line 215 showing the highest PKCepsilon activity. Mice from line 215 exhibited skin changes, including hair loss and inflammation, starting at 4-5 months of age. When subjected to a tumor promotion protocol, these mice showed a significant reduction (95-96%) in papilloma burden compared to wild-type controls. However, they developed carcinomas rapidly, which appeared to form independently of papilloma development. The findings indicated that PKCepsilon played a crucial role in regulating skin tumor development.