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CancerQuest > Newsroom > Articles > New genetic test distinguishes between benign skin growths and melanoma.

New genetic test distinguishes between benign skin growths and melanoma.

Category: Cancer Detection and Diagnosis | Author: Gregg Orloff | Date: Tuesday, January 25, 2011 | Permalink

Melanoma is an aggressive form of skin cancer.  When detected early, melanoma can be surgically removed, with good outcomes.  Researchers from North Carolina, New Mexico and Minnesota have developed a genetic test that is able to determine whether a biopsy sample is melanoma or a non-cancerous growth (nevus; plural-nevi).

While much cancer research focuses on changes in the sequence of DNA (mutations), the researchers chose to look at very subtle changes;they looked at changes in the methylation of the DNA.  Methylation, the addition of a small chemical group to a base in DNA, does not change the sequence of DNA.  Methylation is a type of epigenetic change - an alteration of DNA or chromosomes that does not alter the sequence of bases but does change the activity of the DNA.  An analogy would be decorating a christmas tree.  The tree has not changed but it certainly looks different and has a different 'function'.  Methylation of DNA usually causes the genes involved to be expressed (transcribed) less.

The researchers examined 22 melanoma samples and 27 samples from non-cancerous skin growths (i.e. moles).  After initially looking at a large number of different DNA sites, the researchers were able to identify a set of 22 genes that can be used to separate melanoma from non-cancer, based only on changes in methylation patterns.  Because cancer cells can spread via the bloodstream, the researchers are also attempting to develop a test that would identify metastatic melanoma by looking at DNA from small samples of blood.

Bottom Line: Researchers have identified a 22 gene panel that enables them to accurately determine whether a skin biopsy is benign or melanoma. Work is ongoing to create a diagnostic test that would examine DNA found in blood samples.

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