Question

Regarding skin cancer, Melanoma,

1) What cell type is affected?

2) Describe the defect in cellular reproduction responsible for the cancer.

3) Discuss therapy available for treatment of the disorder. Does the therapy treat the symptoms or the genetic nature of the disease? Explain.

Answer 1

1)

• Melanin pigments are formed in melanocytes within melanosomes.
• Melanoma are skin cancer that occurs in melanocytes.

2)

• Genes, referred to as protooncogenes, promotes cell division.
• While, tumor suppressor genes inhibit the genes under normal conditions.
• If tumor suppressor genes are mutated or lose function, the cell division becomes uncontrolled and cancer is resulted.
• A single allele mutation may result in proto-oncogene.
• Thus, cells from resting phase (G₀) and continues to divide in uncontrolled manner causing tumor or cancer.

3)

Treatments for melanoma:

1. Surgical removal of tumor or affected parts and organs affected.
2. Chemotherapy: Drugs (like Dacarbazine, Temozolomide, Cisplatin) maybe orally taken or injected. Specific targeted therapy like isolated limb perfusion (ILF) or isolated limb infusion (ILI).
3. Radiation: High energy radiation like X-ray may be used to treat affected area.
4. Immunological or biological treatment: Drugs that enhance the immune ability may be incorporated. Example CTLA-4 inhibitors (Ipilimumab). Other therapy includes blocking T-cells like targeting PD-1 (example Opdivo).

These treatments mainly treat the affected cells.

Genetic treatment may be used like:

Targeted therapy:

• This therapy targets specific melanoma cells that affect certain genes.
• Most common therapy includes targeting affected BRAF gene. Drugs like Zelboraf act as BRAF inhibitors.
• Another targeted gene includes MEK gene using MEK inhibitor like Tafinlar.