Richard Harris

It's becoming routine for cancer doctors to order a detailed genetic test of a patient's tumor to help guide treatment, but often those results are ambiguous. Researchers writing in Science Translational Medicine Wednesday say there's a way to make these expensive tests more useful.

Here's the issue: These genomic tests scan hundreds or even thousands of genes looking for mutations that cause or promote cancer growth. In the process, they uncover many mutations that scientists simply don't know how to interpret — some may be harmless.

Scientists have found some unexpected clues that could help explain why 51 percent of the babies born in the United States are male.

It's been a mystery why that ratio isn't 50:50, since that's what basic biology would predict. But scientists have noticed a tilted sex ratio at birth since the 17th century.

The widely held assumption is that this imbalance starts at the very moment of conception — that more males are conceived than females.

When someone asks whether we're winning the war on cancer, the discussion often veers into the world of numbers. And, depending on which numbers you're looking at, the answer can either be yes or no.

Let's start with the no.

The number of cancer deaths in this country is on the rise. It climbed 4 percent between 2000 and 2011, the latest year in official statistics. More than 577,000 people died of cancer in 2011. That's almost a quarter of all deaths. Those aren't just personal tragedies – the figure represents a growing burden on America.

When President Richard Nixon declared a war on cancer in 1971, there were high hopes that scientists were close enough to understanding the underlying causes that many cures were within reach.

We obviously haven't won the war.

In fact, a prominent cancer biologist argues that the conceptual framework for understanding cancer has come full circle over the past 40 years.

"We were really surprised to find that very few people are following the law." - Dr. Monique Anderson, cardiologist, Duke University

Many scientists are failing to live up to a 2007 law that requires them to report the results of their clinical trials to a public website, according to a study in Thursday's New England Journal of Medicine.

The U.S. surgeon general lists 21 deadly diseases that are caused by smoking. Now, a study in this week's New England Journal of Medicine points to more than a dozen other diseases that apparently add to the tobacco death toll.

To arrive at this conclusion, scientists from the American Cancer Society, the National Cancer Institute and several universities tracked nearly a million people for a decade and recorded their causes of death.

On Monday, the first 12 volunteers received an experimental Ebola vaccine in Liberia, launching vaccine trials there. Over the next year or so, scientists hope to inject 27,000 volunteers. The goal is to test two different shots that could protect people from the deadly disease.

Viruses are usually thought of as the bad guys — causing everything from Ebola and AIDS to hepatitis and measles. But scientists have been following the curious story of a particular virus that might actually be good for you.

The virus is called GB Virus-C, and more than a billion people alive today have apparently been infected with it at some point during their lives, says Dr. Jack Stapleton, an infectious disease specialist at the University of Iowa.

Researchers at Harvard and Yale have used some extreme gene-manipulation tools to engineer safety features into designer organisms.

This work goes far beyond traditional genetic engineering, which involves moving a gene from one organism to another. In this case, they're actually rewriting the language of genetics.

The goal is to make modified organisms safer to use, and also to protect them against viruses that can wreak havoc on pharmaceutical production.

Asthma affects children regardless of where they live and whether they are rich or poor. But scientists have long thought that living in poor urban neighborhoods adds an extra risk for this troublesome lung inflammation. A new study suggests that's not necessarily the case.

Asthma is often triggered by something in the environment, so in the 1960s, scientists started looking for places where asthma was especially bad.

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