Discoveries
Too many copies of gene linked to lower survival in melanoma skin cancer
DNA chips help scientists analyze large numbers of genes.
In a classic bad news/good news finding, Dana-Farber scientists and their colleagues have discovered a gene abnormality in the cells of some advanced melanoma patients that worsens the chances of survival, but also might be a target of future drug treatments for the dangerous skin cancer.
Using "microarray" technology that focuses on the building blocks of individual genes, the investigators located regions of chromosomes where genes were either left out or multiplied over and over. In studying cells from melanoma tumors, the team observed as many as 13 extra copies of the MITF gene in 10 percent of primary cancers and 21 percent of metastatic ones. When they checked treatment results of patients from whom the tumor samples were taken, the researchers found poorer five-year survival rates among those whose metastases contained overcopied or "amplified" MITF.
The findings revealed a previously unknown mechanism by which tumors can become "addicted" to a cancer gene that, in its normal form, helps develop and maintain tissues. In such malignancies, the tumor cannot survive without a high level of the protein ordered by the cancer gene.
"By pinpointing the abnormally multiplied MITF cancer gene," says study senior author William Sellers, MD, of Dana-Farber, "we may be able to develop better diagnostic and prognostic tools and provide a target for highly specific therapies for metastatic melanoma patients with this overcopied gene." DNA chips help scientists analyze large numbers of genes.
