Specialized tests useful for melanoma diagnosis, treatment

AMERICAN ACADEMY OF DERMATOLOGY EXPERT

Information provided by Emily Y. Chu, MD, PhD, FAAD, assistant professor of dermatology, and pathology and laboratory medicine, University of Pennsylvania, Philadelphia.

USES

Genetic and molecular testing can provide doctors with important information to aid them in the diagnosis and treatment of certain melanoma cases, Dr. Chu says. These tests are widely available through academic centers and commercial laboratories, she says, and many are covered through insurance or available at no additional cost to the patient.

"Today we have more tools than ever to diagnose and treat melanoma," Dr. Chu says. "These resources enable dermatologists to provide the best possible care for our patients."

Skin cancer is typically diagnosed through tissue biopsy, but biopsy results are sometimes unclear. In these cases, Dr. Chu says, doctors can utilize additional tests to help determine whether a lesion is malignant. Additionally, if a patient is diagnosed with advanced-stage melanoma, testing may be able to identify which treatments are most likely to be effective, she says.

DIAGNOSIS

If a biopsy does not clearly indicate whether a lesion is a malignant melanoma, Dr. Chu says, comparative genomic hybridization or fluorescent in situ hybridization may be helpful in determining a diagnosis. In both of these tests, doctors look for signs of melanoma as they compare the DNA in tumor cells to the DNA in normal tissue.

According to Dr. Chu, doctors also may utilize gene expression profiling to gather additional diagnostic information. This type of test, which screens the patient's tissue for genes associated with cancer, may be used to determine whether a lesion is malignant.

TREATMENT

In advanced melanoma cases, doctors may utilize next generation sequencing testing, which examines a melanoma for specific mutations, allowing doctors to select an appropriate targeted therapy and provide the best possible treatment for the patient.

For example, Dr. Chu says, this type of test may identify BRAF mutations in melanomas, which in turn may be treated with BRAF inhibitors, a type of drug that can shrink tumors and stop further growth by "turning off" cancer genes.

According to Dr. Chu, further research into specific melanoma mutations and targeted therapies could help doctors provide more effective treatment in the future. "Although genetic and molecular testing for melanoma has advanced in recent years, it's still an emerging field," she says. "I think it will only get better."

LIMITATIONS

Patients who have heard of genetic and molecular testing may believe it can determine their risk of melanoma recurrence, Dr. Chu says, but such testing is currently in the early stages of development. While some tools currently available for the general public can estimate one's likelihood of developing certain diseases, including skin cancer, she says, these tests are not necessarily reliable. "Only a doctor can evaluate your melanoma risk or diagnose a suspicious lesion," she says.

While genetic and molecular tests can be a valuable tool for doctors, Dr. Chu says, the results must be considered in conjunction with other diagnostic data. "Test results are just another piece of information," she says, "but in certain melanoma cases, even a little bit of additional information can be helpful to a dermatologist in providing individualized care for each patient."

AMERICAN ACADEMY OF DERMATOLOGY EXPERT ADVICE

"Genetic and molecular tests are a valuable tool in our arsenal for fighting melanoma," Dr. Chu says. "When used appropriately, these tests can provide dermatologists with important information to assist them in melanoma diagnosis and treatment, allowing them to provide patients with the best possible care."