Skin Cancer Overview and Types

Skin Cancer/Carcinoma

• Skin cancer is a common cancer type, including melanoma and non-melanoma skin cancers (BCC and SCC).
• Different types have distinct cause, characteristics, and mechanisms.

Most Likely Causes

• Basal Cell Carcinoma (BCC)
• Primarily caused by UV radiation (sunlight or tanning beds).
• Mutations in the p53 tumor suppressor gene are a key cause.
• Genetic factors leading to mutations in genes controlling cell growth and apoptosis can increase susceptibility.
• Squamous Cell Carcinoma (SCC)
• Caused by cumulative UV radiation exposure.
• UV radiation damages DNA, impairing its repair capacity, leading to mutations in the p53 tumor suppressor gene.
• Chronic irritation (wounds, burns, scars) can also be a contributing factor.
• Melanoma
• Caused by mutations in melanocytes, often triggered by UV radiation.
• UV-induced mutations in oncogenes and tumor suppressor genes (like BRAF and p53) are common.
• Genetic predisposition (family history of melanoma, mutations in genes like CDKN2A) increases risk.

Pathophysiology

• BCC:
• Originates from basal keratinocytes in the epidermis' basal layer.
• UV radiation damages DNA, particularly the p53 tumor suppressor gene, disrupting cell cycle regulation.
• Damaged keratinocytes proliferate uncontrollably, forming nodules or ulcers.
• Typically grows slowly, rarely metastasizes.
• SCC:
• Originates from keratinocytes in sun-exposed areas (e.g., head, neck, arms).
• UV radiation causes mutations in p53 and other tumor suppressor genes, impairing DNA repair.
• Damaged keratinocytes proliferate uncontrollably, developing into fast-growing lesions.
• Has a higher tendency for metastasis to lymph nodes compared to BCC.
• Melanoma:
• Originates from melanocytes (pigment-producing cells of the skin).
• UV radiation damages DNA in critical genes such as BRAF and p53, disrupting cell cycle control.
• Melanocytes proliferate uncontrollably, forming irregular, asymmetrical pigmented lesions, commonly showing ABCDE characteristics (Asymmetry, Border irregularity, Color variations, Diameter >6mm, Evolving).
• Highly metastatic, potentially spreading to distant sites like the brain, liver, and lungs.

Disease Transmission

• Skin cancer is not a transmissible disease. It's caused by genetic mutations, often triggered by UV exposure, rather than an infectious agent.

Risk Factors

• Modifiable: UV radiation exposure (sun, tanning beds), immunosuppression, chronic wounds.
• Non-Modifiable: Age, fair skin, family history, genetic mutations (CDKN2A, BRAF, p53).

Dive into the world of skin cancer, learning about the different types such as melanoma, basal cell carcinoma (BCC), and squamous cell carcinoma (SCC). Each type has distinct causes, characteristics, and genetic factors that contribute to its development. This quiz will enhance your understanding of skin cancer mechanisms and risk factors.