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Archive - Sep 14, 2014

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Scientists Can Now Explain One Third of the Inherited Risk of Prostate Cancer

Scientists can now explain a third of the inherited risk of prostate cancer, after a major international study identified 23 new genetic variants associated with increased risk of the disease. The study brings the total number of common genetic variants linked to prostate cancer to 100, and testing for them can identify 1% of men with a risk of the disease almost six times as high as the population average. Scientists at The Institute of Cancer Research, London, and in Cambridge, UK, and California led a huge search for new genetic variants including almost 90,000 men and for the first time combining populations with European, African, Japanese, and Latino ancestry. The research, published online on September 14, 2014 in Nature Genetics, was funded in equal amounts by Cancer Research UK, Prostate Cancer UK, the EU and the National Institutes for Health in the US. Researchers found that assessing the top 100 variants identified 10% of men with a risk almost three times as high as the population average, and said that this was high enough to investigate whether targeted genetic screening was merited. The researchers plan to lead a new clinical trial to test whether genetic screening can be effective. In European men, scientists had previously found 77 genetic variants which were known to increase the risk of prostate cancer. In the new research, scientists from The Institute of Cancer Research (ICR) (UK), the University of Cambridge (UK), and the University of Southern California in the U.S. examined the genetic information of 87,040 men from all over the world. They combined genetic population studies of 43,303 men with prostate cancer and 43,737 controls from European, African, Japanese, or Latino heritage to improve statistical power and increase their chances of identifying new variants.

Zebrafish Model of a Learning and Memory Disorder in Neurofibromatosis 1 Points to Different Treatment Needs

Using a zebrafish model of a human genetic disease called neurofibromatosis (NF1), a team from the Perelman School of Medicine at the University of Pennsylvania (Penn) has found that the learning and memory components of the disorder are distinct features that will likely need different treatment approaches. The research results were published in the September 11, 2014 issue of Cell Reports. NF1 is one of the most common inherited neurological disorders, affecting approximately one in 3,000 people. It is characterized by tumors, attention deficits, and learning problems. Most people with NF1 have symptoms before the age of 10. Therapies target Ras, a protein family that guides cell proliferation. The NF1 gene encodes neurofibromin, a very large protein with a small domain involved in Ras regulation. Unexpectedly, the Penn team showed that some of the behavioral defects in mutant fish are not related to abnormal Ras, but can be corrected by drugs that affect another signaling pathway controlled by the small molecule cAMP. They used the zebrafish model of NF1 to show that memory defects – such as the recall of a learned task -- can be corrected by drugs that target Ras, while learning deficits are corrected by modulation of the cAMP pathway. Overall, the team's results have implications for potential therapies in people with NF1. "We now know that learning and memory defects in NF1 are distinct and potentially amenable to drug therapy," says co-senior author Jon Epstein, M.D., Chair of the Department of Cell and Developmental Biology. "Our data convincingly show that memory defects in mutant fish are due to abnormal Ras activity, but learning defects are completely unaffected by modulation of these pathways.