Studies of human tumor cells implanted in mice have shown that the abnormal activation of four genes drives the spread of breast cancer to the lungs. The new studies by Howard Hughes Medical Institute researchers reveal that the aberrant genes work together to promote the growth of primary breast tumors. Cooperation among the four genes also enables cancerous cells to escape into the bloodstream and penetrate through blood vessels into lung tissues.

The rich don't get richer -- at least not in laboratory games. According to a new study of behavioral economics, published in the April 12, 2007 issue of Nature, people will spend their own money to make the rich less rich and the poor less poor. They do so without any hope of personal gain, acting, it seems, out of a taste for equality and sense of fair play.

Earth's polar regions. These clouds have grown brighter and more prevalent in recent years and some scientists suggest that changes in these clouds may be the result of climate change.

The first opportunity for launch is on Wednesday, April 25 from Vandenberg Air Force Base, Calif., aboard a Pegasus launch vehicle.

A disturbingly high prevalence of self-reported drinking and driving has been found among Spanish health professionals. Published today in BMC Public Health, the study reveals that Spanish doctors and nurses are self-reporting drink driving at even higher rates than other university graduates.

In a study that could help reveal how illusions are produced in the brain's visual cortex, researchers at the UCSD School of Medicine have found new evidence of rapid integration of auditory and visual sensations in the brain. Their findings, which provide new insight into neural mechanisms by which visual perception can be altered by concurrent auditory events, will be published online in the April 12 edition of the Journal of Neuroscience.

Unique three-dimensional solar cells that capture nearly all of the light that strikes them could boost the efficiency of photovoltaic (PV) systems while reducing their size, weight and mechanical complexity.

The new 3D solar cells capture photons from sunlight using an array of miniature "tower" structures that resemble high-rise buildings in a city street grid.