Treating cancer is a bit like shooting in the dark. Sometimes it works. Sometimes it doesn't. There's no

way to predict. That's because while scientists have some crude ideas about how to disable cancer cells,

the inner workings of cancer are a mystery for the most part. Perhaps not for long. Researchers have just sequenced the entire DNA code of one type of

breast-cancer tumor. The team, led by scientists at Washington University School of Medicine, began the

project using tumor samples from 50 women enrolled in another of their studies. All the women had

breast tumors that contained estrogen receptors, but only about half the patients had responded to drugs

that targeted the receptors. To figure out why, the researchers sequenced the whole genomes of the

breast cancers of all 50 women.

The genetic maps provided some intriguing clues: the patients' tumors harbored more than 1,700 genetic

mutations, most of which were unique to the women in whom they originated. Of the few gene mutations

shared by many of the women, some were familiar--previously associated with cancer in other

studies--and some were completely new. Those aberrations could help explain why the women

responded differently to the drugs. And although the sheer number of genetic abnormalities suggests that

cancer may vary from one person to the next, most of the changes actually fed into common pathways of

tumor development. These, say the authors, could become targets of broadly useful new drugs. Indeed,

there are already drugs on the market that address six of the mutations, and doctors are eager to test

their effectiveness against breast cancer.

A similar genetic dossier from dozens of tumors exists for one other cancer, multiple myeloma. Together,

these sets of genomes represent a new era in cancer treatment, in which doctors may finally be able to

match each patient to the best possible treatment.

ALZHEIMER'S

Scientists Identify Five New Genes

In a genetic analysis of more than 50,000 people, researchers have discovered five new genes that raise

the risk of late-onset Alzheimer's disease. The additions, which bring the total number of known risk

genes to 10, are associated with the disorder's most common form, which affects up to 50% of people

over age 80.

Experts are excited because the newly revealed genes involve things that scientists have long suspected

of playing a role in Alzheimer's but have never been able to confirm: high cholesterol, inflammation and

the way cells ferry molecules around. Already existing genetic risk factors are generally related to the

formation and accumulation in the brain of the disease's hallmark amyloid plaques.

The new genes together may account for only about 35% of late-onset Alzheimer's cases, but the novel

processes they implicate could provide fresh targets for better drugs. Currently, the best medications can

only alleviate, not prevent, the main symptom, memory loss. It's a long way from genes to therapy, but

the new discoveries are an important step in that direction.

DIET

Fasting for Your Heart

Starving yourself isn't healthy, but periodic fasts may actually be good for your ticker. Researchers in Utah show that a 24-hour fast can lead to favorable changes in cholesterol and

blood-sugar levels, which suggests that supervised fasting may help combat heart-disease risk. But even

the authors aren't ready to endorse it just yet--at least not until further work reveals whether there is a

safe way to skip calories. Not eating triggers the stress response, so repeated episodes of fasting may

end up straining and damaging the heart.