A better way to find brain tumors

Scientists have devised a more accurate, less invasive way to detect brain cancer regrowth.

Currently, physicians treat patients with an aggressive form of brain cancer called glioblastoma by removing the tumor and prescribing radiation and chemotherapy. Physicians then use MRI scans to look for tumor regrowth.

But radiation can kill healthy tissue, which on an MRI looks similar to a tumor mass and often leads to a misdiagnosis. However, using a simple blood test that looks for tiny sacs of genetic material called exosomes - which are shed by brain cancer cells in mass quantities - physicians can track tumor regrowth.

Johan Skog, a scientist with Massachusetts General Hospital and Harvard Medical School, working with senior researcher Xandra Breakefield, also isolated exosomes from human brain cancer tissue samples and analyzed them for genetic mutations known to be involved in glioblastoma tumors.

"This is the first time anyone has shown that a mutational profile of the tumor can be found in the exosomes," said Skog. It's an important finding not only for tracking regrowth, he said, but also to monitor new genetic mutations produced by cancer cells. That, in turn, can signal the need for a different drug therapy.

BOTTOM LINE: A blood test that screens for exosomes could help physicians diagnose tumor regrowth in brain cancer patients.

CAUTIONS: This study is preliminary, including blood samples from 30 patients. To better test the accuracy of the blood test, scientists must conduct a much larger patient study.

WHAT'S NEXT: Researchers are repeating the study using samples from as many as 200 brain cancer patients. They also want to see if exosomes are present in other types of cancer.

WHERE TO FIND IT: Nature Cell Biology, December 2008

KELLI WHITLOCK BURTON

Adequate sleep is becoming a rare commodity in modern societies, with daily sleep durations dropping by nearly 2 hours in the United States during the past four decades.

While shirking on sleep may let Americans catch that late night show or finish that last-minute presentation, the detrimental effects are becoming increasingly clear, as studies link poor sleep habits to cardiovascular diseases such as heart attacks and strokes.

Curious about the relationship between sleep and heart disease, Dr. Kazuo Eguchi and colleagues from Jichi Medical University in Japan examined more than 1200 elderly patients with high blood pressure for 50 months. They noted average sleep duration, blood pressure, and the development of heart disease in the patients. The scientists found that patients who slept fewer than 7.5 hours each night had a 1 1/2-fold higher risk of having a heart attack or stroke.

Further, patients with poor sleep were especially at risk for developing heart disease if they also had high blood pressure at night. Poor sleep habits and high blood pressure may work together at increasing the risk for heart disease, so improving both may be critical in reducing insult to the heart.

BOTTOM LINE: Sleeping fewer than 7.5 hours increases the risk of cardiovascular disease, with a further increase in risk in patients with high blood pressure at night.

CAUTIONS: Most of the patients were elderly, so it's unclear whether the results can be applied to a younger population.

WHAT'S NEXT: Researchers will need to study the role of sleep, blood pressure, and cardiovascular risk in younger populations.

WHERE TO FIND IT: The Archives of Internal Medicine, Nov. 10, 2008.

SUSHRUT JANGI