Technology sets its sights on melanoma and early diagnosis

June 1, 2008

According to one expert, gene profiling using tape stripping, the MelaFind® device as well as confocal microscopy have the potential to assist the dermatologist in catching melanoma early on.

Key Points

Miami - According to one expert, three techniques may potentially assist the dermatologist in the clinical evaluation of melanoma: gene profiling, the MelaFind device (Electro-Optical Sciences) and confocal microscopy.

"These devices have a real potential to significantly bring that percentage a lot higher, so that we can catch melanoma at a much earlier time," says Harold Rabinovitz, M.D., a dermatologist in private practice and clinical professor, department of dermatology, University of Miami.

Gene profiling

The stratum corneum RNA is harvested by tape stripping, and then this RNA is converted to DNA and amplified by the enzyme reverse transcriptase. This allows the genes that are expressed in a lesion to be identified via microarray-based gene expression profiling to create a multi-gene classifier.

"Though this technique is in its early stages, preliminary results using this technique are promising, and demonstrate that one could distinguish melanoma from normal skin from a simple tape stripping, and that there are differences in the gene profile among the atypical nevi.

"It was found that a 20-gene classifier could accurately discriminate melanoma from atypical nevi," Dr. Rabinovitz tells Dermatology Times. He says this diagnostic tool shows promise in discerning melanoma from atypical nevi.

MelaFind device

MelaFind is a device that uses machine vision - a computer-automated analysis of pigmented skin lesions.

The goal is to have a reliable, noninvasive, practical diagnostic tool to aid in the detection of melanoma, to help save patients' lives and reduce the number of unnecessary biopsies.

"The MelaFind device emits multiple wavelengths of light, and captures digital images of lesions, analyzes them and separates pigmented lesions from melanoma.

"These are multi-spectral bands which range from blue through near infrared," Dr. Rabinovitz says.

In a blinded test study done with this device, 54 melanoma, 22 high-graded dysplastic nevi and 486 other pigmented skin lesions were analyzed.

Results showed that the dermatologist, in terms of the sensitivity, was 98.1 percent on target in diagnosing the lesions, missing one invasive melanoma.

The computer was also 98.1 percent accurate, missing one melanoma in situ. However, the specificities were markedly different.

Dr. Rabinovitz says this is the only device that is currently undergoing phase 3 Food and Drug Administration (FDA) trials, and the guidelines are strict.

The primary endpoint of the MelaFind study is a 99 percent diagnosis of 100 melanomas. The MelaFind specificity must be superior to the specificity of the study dermatologist in order for the device to be approved by the FDA.

Confocal microscopy

The confocal microscope works by emitting a laser beam of light that, when it hits the skin, is reflected back into an aperture. Through this sight, one can see layers of the skin and detailed anatomy of the epidermal-dermal junction.

"It is an exciting tool, because it potentially allows you to do virtual pathology," Dr. Rabinovitz says.

The confocal may be limited in evaluating the depth of a lesion, but in most lesions, it is important to visualize what is happening in the epidermis or at the dermal-epidermal junction.

"Unlike the gene profiling and MelaFind techniques, which are designed to assist in the early diagnosis of melanoma, the confocal microscope does not only look at melanoma, but it can also help diagnose a whole array of different types of skin diseases, from pigmented lesions to inflammatory dermatoses, helping the clinician learn from disease processes," Dr. Rabinovitz says.

Disclosures: Dr. Rabinovitz is medical director for Electro-Optical Sciences, a clinical investigator and consultant for DermTech (tape stripping), and a clinical investigator for Lucid (confocal microscope).

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