PET scans of the brain


In a common genetic disorder, a blood test reveals when benign tumours turn cancerous

People with an inherited condition known as neurofibromatosis type 1, or NF1, often develop non-cancerous, or benign, tumours that grow along nerves. These tumours can sometimes turn into aggressive cancers, but there hasn’t been a good way to determine whether this transformation to cancer has happened. Researchers from the National Cancer Institute’s (NCI) Center for Cancer Research, part of the National Institutes of Health, and Washington University School of Medicine in St. Louis have developed a blood test that, they believe, could one day offer a highly sensitive and inexpensive approach to detect cancer early in people with NF1. The blood test could also help doctors monitor how well patients are responding to treatment for their cancer. The findings are published in the August 31 issue of PLOS Medicine.  NF1 is the most common cancer predisposition syndrome, affecting 1 in 3,000 people worldwide. The condition, caused by a mutation in a gene called NF1, is almost always diagnosed in childhood. Roughly half of the people with NF1 will develop large but benign tumours on nerves, called plexiform neurofibromas. In up to 15% of people with plexiform neurofibromas, these benign tumours turn into an aggressive form of cancer known as malignant peripheral nerve sheath tumour or MPNST. Patients with MPNST have a poor prognosis because cancer can quickly spread and often becomes resistant to both chemotherapy and radiation. Among people diagnosed with MPNST, 80% die within five years. “Imagine going through life with a cancer predisposition syndrome like NF1. It’s kind of like a ticking bomb,” said study co-author Jack F. Shern, M.D., a Lasker Clinical Research Scholar in NCI’s Pediatric Oncology Branch. “The doctors are going to be watching for cancerous tumours, and you’re going to be watching for them, but you really want to discover that transformation to cancer as early as possible.” Doctors currently use either imaging scans (MRI or PET scan) or biopsies to determine if plexiform neurofibromas have transformed into MPNST. However, biopsy findings aren’t always accurate and the procedure can be extremely painful for patients because the tumours grow along nerves. Imaging tests, meanwhile, are…

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New blood test method may predict Alzheimer’s disease

Diagnostic value of plasma phosphorylated tau181 in Alzheimer’s disease and frontotemporal lobar degeneration. New Delhi, 12th March 2020. Alzheimer’s disease is an age-related brain disorder that develops over many years. Toxic changes in the brain slowly destroy memory and thinking skills. Alzheimer’s Symptoms most often first appear when people are in their mid-60s. The disorder gets worse over time and eventually leads to severe loss of mental function. What is beta-amyloid and tau The process that destroys the brain involves two proteins called beta-amyloid and tau. Beta-amyloid clumps into plaques, which slowly build up between brain cells. Abnormal tau accumulates inside brain cells, forming tangles. Researchers have found that PET scans of the brain and lab tests of spinal fluid can reveal disease-related changes, or pathology, twenty years before the onset of symptoms. Although the disorder is not reversable, early treatment may help preserve daily functioning for some time. Early diagnosis of Alzheimer would also enable testing of novel drugs and other treatment approaches. However, PET imaging is expensive and involves radioactive agents, and spinal fluid tests are invasive, complex, and time-consuming. Researchers are looking for simpler, more cost-effective tests. A team led by Dr. Adam Boxer at the University of California, San Francisco investigated whether a new blood testing technique called Simoa could be used to measure the concentrations of tau and predict development of Alzheimer’s disease. The study was funded in part by NIH’s National Institute on Aging (NIA) affiliated to U.S. Department of Health and Human Services (USA), National Institute of Neurological Disorders and Stroke (NINDS), and National Center for Advancing Translational Sciences (NCATS). Results were published online on March 2, 2020, in Nature Medicine. The team collected blood samples from more than 400 people. They measured the concentration of ptau181—a modified version of tau that’s been linked with Alzheimer’s disease—in blood plasma, the liquid part of blood. Their analysis showed that the ptau181 in plasma differed between healthy participants and those with Alzheimer’s pathology confirmed in autopsies. The test could also differentiate Alzheimer’s pathology from a group of rare neurodegenerative diseases known collectively as frontotemporal lobar degeneration. The…