Expression of specific gene differentiates moles from melanoma

November 21, 2016

Most melanomas are driven by mutations that spur out-of-control cell replication, while nevi (moles composed of non-cancerous cells at the skin surface) harboring the same mutations do not grow wildly. However, changes in the level of gene expression can cause nevi to become melanomas. Dermatologists surmise that 30 to 40 percent of melanomas (approximately 30,000 cases per year) may arise in association with a nevus. However, clinicians would like to be able to better distinguish between the two, especially in borderline cases when they examine skin tissue after a patient biopsy.

Senior author John T. Seykora, MD, PhD, a professor of Dermatology in the Perelman School of Medicine at the University of Pennsylvania, led a study that found that decreased levels of the gene p15 represents a way to determine if a nevus is transitioning to a . The protein p15 functions to inhibit nevus cell proliferation. They published their findings in the most recent issue of the American Journal of Pathology.

"We showed that p15 expression is a robust biomarker for distinguishing nevus from melanoma," said Seykora. "Making this distinction has been a long-standing issue for dermatologists. We hope that this new finding will help doctors determine if a nevus has transformed to melanoma. This could help doctors and patients in difficult cases. Current research will hopefully move this into the realm of standard practice in about one to two years."

Decreased expression in the related protein p16 has also been associated with melanoma, but p15 appears to be a primary driver of oncogene-induced cell senescence in nevus cells. When p15 levels drop, then nevus cells begin to grow.

The team stained human nevus and melanoma tissue samples with p15 and p16 antibodies. Staining was evaluated and graded for percentage and intensity to determine an "H score," which correlates with the level of protein in the cells. This approach could also form the basis of a clinical determination, taking the form of an antibody test for p15 from a patient's biopsy specimen. "If the staining level is high then that would be most consistent with a benign nevus," Seykora said. "If the staining level is low then that would be consistent with a melanoma."

RNA was also extracted from 14 nevus and melanoma tissue samples to determine levels of p15 mRNA. The expression of p15 mRNA was significantly increased in melanocytic nevi compared with melanomas as determined by real-time quantitative RT-PCR analysis.

Explore further: Negative pigment network able to distinguish melanoma

Related Stories

Negative pigment network able to distinguish melanoma

October 25, 2012
(HealthDay)—Negative pigment network (NPN) can be used to distinguish melanoma from Spitz nevus and other benign lesions, according to a study published online Oct. 11 in the Journal of the American Academy of Dermatology.

Decrease in nevus biopsies with total body photography

June 23, 2016
(HealthDay)—Total body photography (TBP) is associated with a reduction in nevus biopsies, according to a study published in the July issue of the Journal of the American Academy of Dermatology.

Dermoscopically, melanoma, spitz nevi indistinguishable

December 22, 2014
(HealthDay)—Melanoma may be dermoscopically indistinguishable from Spitz nevi, according to a study published in the January issue of the Journal of the American Academy of Dermatology.

Skin cancer may develop during laser removal of tattoo

August 2, 2013
(HealthDay)—Malignant melanoma may develop on a preexisting nevus within a tattoo that is being removed with laser therapy, according to a case report published online July 31 in JAMA Dermatology.

Study of patients with melanoma finds most have few moles

March 2, 2016
Most patients with melanoma had few moles and no atypical moles, and in patients younger than 60, thick melanomas were more commonly found in those with fewer moles but more atypical moles, according to an article published ...

Pathologists tend to reclassify prior nonmalignant diagnoses

August 17, 2012
(HealthDay) -- For dermatopathologists there is a trend toward reclassification of prior nonmalignant diagnoses of severely atypical dysplastic nevi as malignant, according to a study published in the September issue of the ...

Recommended for you

New findings explain how UV rays trigger skin cancer

October 18, 2017
Melanoma, a cancer of skin pigment cells called melanocytes, will strike an estimated 87,110 people in the U.S. in 2017, according to the Centers for Disease Control and Prevention. A fraction of those melanomas come from ...

Drug yields high response rates for lung cancer patients with harsh mutation

October 18, 2017
A targeted therapy resurrected by the Moon Shots Program at The University of Texas MD Anderson Cancer Center has produced unprecedented response rates among patients with metastatic non-small cell lung cancer that carries ...

Possible new immune therapy target in lung cancer

October 18, 2017
A study from Bern University Hospital in collaboration with the University of Bern shows that so-called perivascular-like cells from lung tumors behave abnormally. They not only inadequately support vascular structures, but ...

Many pelvic tumors in women may have common origin—fallopian tubes

October 17, 2017
Most—and possibly all—ovarian cancers start, not in ovaries, but instead in the fallopian tubes attached to them.

Researchers find novel mechanism of resistance to anti-cancer drugs

October 17, 2017
The targeted anti-cancer therapies cetuximab and panitumumab are mainstays of treatment for advanced colorectal cancer, the second leading cause of cancer-related deaths in the United States. However, many patients have tumors ...

New bowel cancer drug target discovered

October 17, 2017
Researchers at the Francis Crick Institute have discovered a new drug target for bowel cancer that is specific to tumour cells and therefore less toxic than conventional therapies.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.