Abstract: Non-human mammalian animals having a higher epidermal expression level of protein kinase C&egr; than their wild-type counterparts are phenotypically distinguished from wild-type animals in that the animals induced to develop tumors in a chemical initiation/promotion protocol are suppressed for subsequent papilloma development but are susceptible to developing squamous cell carcinoma and metastatic squamous cell carcinoma. The animals are advantageously used in methods for screening putative agents for altering the susceptibility, development and progression of squamous cell carcinoma and metastatic squamous cell carcinoma and have further commercial value as tools for investigating the development of metastatic disease.