Polyomavirus-Induced Pilomatricomas in Mice: From Viral Inoculation to Tumor Development

The study demonstrated that Polyomavirus A2 infection in 30 newborn C3H/BiDa mice led to the development of pilomatricomas, a type of hair follicle tumor, over 70 days. The virus initially replicated in the skin, spread through the blood, and infected hair follicle cells, causing tumors characterized by matrix cell proliferation and differentiation into 'shadow' cells and keratin. Viral replication was observed in differentiated cells, not in proliferating ones, indicating that the type of infected cell influenced the infection and transformation process. The findings provided a model for studying the mechanisms of hair follicle neoplasms and suggested a potential role for polyomaviruses in human cancers.