Seven potential immunotherapy targets for treatment of melanoma identified
NCI scientists, using a unique digital technology that counts RNA molecules in small amounts of tumor tissue, identified seven potential immunotherapy targets for treatment of melanoma. Immunotherapy works by boosting the body’s immune system, or by using immune cells to attack specific types of cancer cells. The success of this treatment for melanoma, and all forms of cancer, is contingent upon finding protein targets that are overexpressed, or highly active, on cancerous tumor cells, but have limited expression in normal tissue. The seven gene targets identified in this work meet these criteria. The results of this study, headed by Richard A. Morgan, Ph.D., Surgery Branch, Tumor Immunology Section, Center for Cancer Research at NCI, appeared Sept. 10, 2013, in Clinical Cancer Research.
Morgan and his colleagues designed a set of genetic probes that contained 97 genes, 72 of which were considered potential candidate genes for immunotherapy, to look for new therapeutic targets in melanoma. Each of these genetic probes had a unique fluorescent bar code that permitted the NCI research team to accurately count individual RNA molecules. Using this probe set on 59 melanoma tumor samples, the researchers isolated RNA, which is the genetic material that codes for proteins, and counted each time a specific gene bar code was observed. As a result of this experiment, the scientists concluded that of 72 potential target genes, 33 were overexpressed in more than 20 percent of the melanoma tumor samples. Twenty of those genes were identified as being expressed in different manners between tumor samples and normal tissue. Based on this analysis, the researchers concluded that seven genes warrant further consideration as potential immunotherapy targets: CSAG2, MAGEA3, MAGEC2, IL13RA2, PRAME, CSPG4, and SOX10, because they were found to be highly overexpressed in a large percent of the tumor samples but had limited expression in normal tissues.