Exciting new research findings have identified what makes Retinoblastoma, an aggressive but rare form of cancer of the retina in children, grow so quickly. The study was reported in The Wall Street Journal's Marketwatch.
Retinoblastoma is found in more than 5,000 children each year worldwide; most are age 5 or younger, and some are infants making them among the youngest cancer patients.
Researchers at the Pediatric Cancer Genome Project (PCGP), a collaboration between scientists at St. Jude Children's Research Hospital and Washington University School of Medicine in St Louis, have also uncovered a new treatment therapy that could potentially save children from undergoing invasive surgery and subsequently losing their sight, in particular for those with tumors in both eyes.
The study, published in the January edition of Nature, links tumor growth, initiated by the loss of RB1, a tumor suppressor gene, to the underlying mechanism that enable it to grow; evidence shows that the makeup of the genes themselves do not change, suggesting the cancer activity is due to reversible chemical changes and not genetic mutation.
"The dogma in the field has been that once RB1 is mutated, the genome of the affected cell becomes unstable, chromosomes begin to break and recombine, and mutations quickly develop in the pathways that are essential for cancer progression," said Michael Dyer, Ph.D., above, director of the Department of Developmental Neurobiology at St. Jude and a researcher in the study.
"What we found was exactly the opposite. These tumors contain very few mutations or chromosomal rearrangements."
The retinoblastoma tumors sequenced contained about 15-fold fewer mutations than have been found in nearly all other cancers sequenced so far. In one patient's tumor, RB1 was the only mutation.
The findings prompted researchers to look at differences in the patterns of gene activity in tumor and normal tissue. They discovered that the tumor samples had high levels of the protein SYK, normally required for blood development but which has no role in normal eye development. When they checked SYK protein levels in normal and retinoblastoma tissue, they found high levels of the protein in 82 tumor samples and absent in normal tissue. Human retinoblastoma cells in the lab died as a result of experimental drugs used to block SYK, opening up the possibility of new treatment therapies.
The PCGP is a 3 year joint project, starting in 2010, that aims to decode the genomes of more than 600 childhood cancer patients in order to identify genetic mistakes that lead to cancer.
Written for California's Children by Elizabeth J Carlyle.
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