Melanoma

Melanoma is a disease in which malignant (cancer) cells form in the skin cells called melanocytes. It is more aggressive than nonmelanoma skin cancers.

Symptoms and Diagnosis

These and other symptoms may be caused by melanoma or by other conditions. A doctor should be consulted if any of the following problems occur:

• A mole that:
  • changes in size, shape, or color.
  • has irregular edges or borders.
  • is more than 1 color.
  • is asymmetrical.
  • itches.
  • oozes, bleeds, or is ulcerated (a hole forms in the skin when the top layer of cells breaks down and the underlying tissue shows through).
• Change in pigmented (colored) skin.
• Satellite moles (new moles that grow near an existing mole).

The following tests and procedures can help detect and diagnose melanoma:

• Skin examination: A doctor or nurse examines the skin to look for moles, birthmarks, or other pigmented areas that look abnormal in color, size, shape, or texture.
• Biopsy: A local excision is done to remove as much of the suspicious mole or lesion as possible. A pathologist then looks at the tissue under a microscope to check for cancer cells. Because melanoma can be hard to diagnose, patients should consider having their biopsy sample checked by a second pathologist.

Suspicious areas should not be shaved off or cauterized (destroyed with a hot instrument, an electrical current, or a caustic substance).

Causes

All cancers are caused by dysfunctions of proteins involved in cell division, apoptosis, or DNA repair (see general characteristics). Dysfunctional proteins may arise from gene mutations or protein interactions with environments. Several genes are known to be associated with melanoma (more info). The following risk factors may increase the chance of developing melanoma:

• Unusual moles.
• Exposure to natural sunlight.
• Exposure to artificial ultraviolet light (tanning booth).
• Family or personal history of melanoma.
• Being white and older than 20 years.
• Red or blond hair.
• White or light-colored skin and freckles.
• Blue eyes.

Reference:

National Cancer Institute, USA.