Skin tumor development and keratin expression in different experimental models. Relation to inducing agent and target...

Area of Science:

• Dermatology
• Oncology
• Toxicology

Background:

• The experimental skin carcinogenesis model is crucial for understanding tumor development.
• Investigating neoplastic processes requires analyzing differentiation markers like keratins.

Purpose of the Study:

• To assess the applicability of the experimental skin carcinogenesis model.
• To analyze skin tumor development and progression in various mouse strains under different carcinogen and UV radiation regimens.
• To determine the role of differentiation markers, such as keratins, in skin carcinogenesis.

Main Methods:

• Exposing the skin of various mouse strains to chemical carcinogens (7,12-dimethylbenz(a)-anthracene, benzo(a)pyrene) and UV radiation (UVB, UVA).
• Analyzing epidermal cell differentiation, structural irregularities, and keratin expression.
• Quantifying tumor types (papillomas, squamous cell carcinomas, spindle cell tumors) and their characteristics.

Main Results:

• 7,12-dimethylbenz(a)-anthracene (DMBA) induced abnormal differentiation, altered keratin expression, papillomas, and squamous cell carcinomas in NMRI mice.
• UVB irradiation enhanced DMBA-induced tumors; high-dose UVB caused undifferentiated spindle cell tumors.
• Tumor development varied significantly across mouse strains (NMRI, C57BL/6, hr/hr, DBA/2, SKH-1) based on skin structure (pigmentation, hair) and induction regimen.

Conclusions:

• The extent and type of skin tumor development are dependent on the induction regimen (chemical, physical, dose, duration).
• Skin structure, including pigmentation and adnexal development, significantly influences carcinogenesis outcomes.
• These factors must be considered when extrapolating experimental findings to human conditions.