Sun exposure has a step-wise worsening progression

1. Acitinic keratosis
2. Bowen’s disease
3. SCC

UV light malignancy development

2 main types of UV light

• UVA - Involved in accelerating skin aging
  • indirectly damages DNA by stimulating free radical production
• UVB - more damaging type (more carcinogenic), infiltrates epidermis and causes DNA damage

Skin cancer development - UV penetrates skin:

• UVA - dermis
• UVB - basal epidermis
• UVC - superficial

BCC and SCC induce p53 mutations = uncontrolled cellular proliferation (p53 usually induces apoptosis in response to cellular stress)

Melanoma - BRAF mutations