December 21, 2012
Cancer Researchers Find Potential Genetic Culprit For Melanoma
Connie K. Ho for redOrbit.com — Your Universe Online
Researchers from the University of Colorado Cancer Center say that they have discovered a new, more targeted way of treating melanoma, the most deadly form of skin cancer.
The findings, described in a recent edition of the Journal of Investigative Dermatology, describe how small pieces of genetic material known as MicroRNA can choose the genes in a DNA cell that are either expressed or kept silent. With melanoma in particular, the researchers discovered a deficiency of microRNA-26a that usually silences the gene SODD.
“It´s a double negative,” explained the study's co-senior author Yiqun Shellman, an investigator at the University of Colorado Cancer Center and associate professor at the University of Colorado School of Medicine, in a prepared statement. “MiR-26a works to stop the growth of cancer. You turn off this thing that should stop growth, and you have growth.”
In the study, melanoma cell lines that lacked microRNA-26a were reintroduced to the cell in a lab. As a result, there was a reduction in cancer cell survival and the microRNA-26a eliminated melanoma cells while leaving healthy cells alive. The team of investigators was able to compare the expression of microRNA in healthy cells to the expression of microRNA in melanoma cells.
“We hoped the difference between microRNA expression in healthy and melanoma cells would show which ones were contributing to tumorgenesis,” continued Shellman in the statement.
The researchers saw that the expression of micro-RNA-26 was consistently different between healthy and cancerous cells. Some, but not all, of the melanoma cells were eliminated by the replacement introduction of mRNA.
“The first step is to further pinpoint the genetic signatures of the patients likely to benefit from microRNA-26a replacement therapy,” noted Shellman in the statement. “Maybe it´s simply the downregulation of microRNA-26a itself, or maybe we can use SODD expression as the biomarker.”
Moving forward, Shellman believes that her team´s discovery of the role of MicroRNA in the development of carcinoma in cell cultures may eventually help develope new therapeutic techniques that could be used in real cancer patients.
The National Institutes of Health (NIH) considers melanoma the most dangerous form of skin cancer, and it is the leading cause of death due to skin disease. It is related to changes in melanocytes, which are skin cells that produce the skin pigment melanin. Melanin levels control skin and hair color, with light-skinned people or those living in sunny environments having a higher risk of developing melanoma over time. Individuals who have a growth, lump, sore, mole, or other sign of melanoma or skin cancer that is abnormal or changes in colors should consult a physician.
The NIH also provides a set of recommendations for preventing the development of melanoma. For example, the American Cancer Society advises annual skin examinations for individuals older than 40 years of age and skin examinations every three years for individuals between the ages of 20 and 40. Additionally, individuals should apply high-quality sunscreen to all exposed areas when spending time in the sun. The sunscreen should be waterproof and able to block both UVA and UVB light.