Our weekly roundup of the latest developments in the world of health.

This week we look at genes and the effectiveness of a breast cancer drug and at a possible vaccine against traveler's diarrhea.
Stay well.

This Issue:

Tamoxifen and Genetics
Traveler's Diarrhea Vaccine

In the News:

Tamoxifen and Genetics

A woman's genes may affect whether she responds to the breast cancer drug tamoxifen. A study published in the Journal of Clinical Oncology offers an explanation for why the drug is not as effective at preventing cancer recurrence in some women. Tamoxifen becomes particularly effective at fighting cancer when it interacts with a specific liver enzyme, The New York Times News Service reports. In the study, researchers found that some women have inherited lower levels of this liver enzyme, which hinders tamoxifen effectiveness. Women taking tamoxifen with this genetic trait were almost twice as likely to have a recurrence of breast cancer compared to other women on tamoxifen, the researchers found. They say their findings could help doctors and patients to select the best breast cancer treatment; for example, women with the genetic change might get more benefit taking a drug from the class known as aromatase inhibitors.

Traveler's Diarrhea Vaccine

It may soon be possible to avoid one of the pitfalls of travel -- traveler's diarrhea (also known as enterotoxigenic E. coli, or ETEC). An experimental ETEC vaccine appears to lessen the severity of the illness in some people, according to a report presented at the American Society of Microbiology meeting. Swedish researchers tested the vaccine -- which uses part of a cholera vaccine and killed E. coli bacteria -- on some 1,400 U.S. students traveling in Mexico and Guatemala. Blood tests revealed that only about half the students "responded" to the vaccine, The Associated Press reports. But among those who developed an immune response, the vaccine was 84% effective at blocking severe diarrhea, and 63% effective at blocking mild diarrhea. It also halved the number of days the students who developed diarrhea were sick, the AP says. The researchers say more work is needed to determine why the vaccine doesn't "take" in some people.

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