The electric fields' different effects on normal and dividing cells mostly have to do with geometry. A dividing cell has what Palti calls "an hourglass shape rather than a round shape." The electric field generated by the NovoCure device passes around and through round cells in a uniform fashion. But the narrow neck that pinches in at the center of a dividing cell acts like a lens, concentrating the electric field at this point. This non-uniform electric field wreaks havoc on dividing cells. The electric field tears apart important biological molecules, such as DNA and the structural proteins that pull the chromosomes into place during cell division. Dividing cells simply "disintegrate," says Palti.

Palti, who for years has been studying the effect of electric fields on cancer and normal cells, says that he has verified this mechanism in computer models and experiments in the lab. "The physics are solid," says David Cohen, associate professor of radiology at Harvard Medical School.

Patients in the glioblastoma clinical trial wear the device almost constantly, carrying necessary components in a briefcase. A wire emerging from the briefcase connects to adhesive electrodes covering the skull. Alternating electric fields pass through the scalp, into the skull, and on to the brain. The Food and Drug Administration approved the device for late-stage clinical trials for glioblastoma following promising results from a pilot study in 10 patients, one of whom had a complete recovery.

An experimental ultrasound technique that measures how easily breast lumps compress and bounce back could enable doctors to determine instantly whether a woman has cancer or not without doing a biopsy.

In a small study of 80 women, the technique -- called "elastography" -- distinguished harmless lumps from malignant ones with nearly 100 percent accuracy.

If the results hold up in a larger study, elastography could save thousands of women from the waiting, cost, discomfort and anxiety of a biopsy, in which cells are removed from the breast -- sometimes with a needle, sometimes with a scalpel -- and examined under a microscope.

"There's a lot of anxiety, a lot of stress, a lot of fear involved" with biopsies, said Susan Brown, manager of health education for the Susan G. Komen Breast Cancer Foundation. "And there's the cost of leaving work to make a second appointment. If this can be done instead of a biopsy, there would be a real cost reduction."

To explain elastography, Ophir likens the body to a box-spring mattress, but "a crazy mattress made out of millions of small springs and each one is a little different. Each is moving around at a different rate, depending on their individual stiffness." Cancerous tumors are like stiff springs. Normal tissue and benign lesions compress more easily.

A team from the University of Pennsylvania School of Medicine has shown that by using a cancer vaccine based on the bacterium Listeria monocytogenes, they can cure mice with established breast tumors. Cancer vaccines, which are more properly described as immunotherapy, work by boosting an immune response against tumor-associated antigens. Using Listeria, the researchers, led by Yvonne Paterson, PhD, Professor of Microbiology, delivered the tumor-associated antigen HER-2/Neu to immune cells. HER-2/Neu is overexpressed in 20 to 40 percent of all breast cancers and also present in many cancers of the ovaries, lung, pancreas, and gastrointestinal tract. These cells eventually enlist killer T cells to seek out and destroy the tumor cells that display the HER-2/Neu molecule.

"We found that we can stop the tumor from growing out to 100 days, at which time we stopped measuring since this is a long time for experiments of this type," says Paterson. "The tumors stopped growing or went completely away." The researchers published their findings in the September 15 issue of The Journal of Immunology.

"It took a while to dissect what elements of an immune response were best able to cause the rejection of established tumors," she says. "But in the last couple of years it has paid off and we are very excited to see the technology finally being tested in cancer patients. The dream of the cancer immunotherapist is to provide an alternative and more humane way of controlling metastatic disease than current chemotherapies."

Scientists from Denmark drew their conclusions after studying 6,689 women over a period of 18 years, and speculated that it may be because daily stress suppressed production of estrogen, which is a risk factor in breast cancer.

"Prolonged-low key stress of everyday life results in a persistent activation of stress hormones which may impair estrogen synthesis and may therefore be related to lower risk of breast cancer," they wrote.

However, they warned that stress was not a health cure, given that high levels had also been associated with increased risk of potential killers like heart disease.

They also noted that their findings were at odds with studies in Finland and Sweden -- the former found no link between daily stress and breast cancer while the latter found a direct association with higher risk.