Human tumors grown in mouse models have long been used to test promising anti-cancer therapies. However, when a human tumor is transplanted into a mouse, the mouse immune system must be knocked down so that it doesn't attack the foreign tumor tissue, thus allowing the tumor to grow. A University of Colorado Cancer Center study describes a new model, XactMice, in which human blood stem cells are used to grow a "humanized" mouse immune system prior to tumor transplantation.

As the search continues for Earth-size planets orbiting at just the right distance from their star, a region termed the habitable zone, the number of potentially life-supporting planets grows. In two decades we have progressed from having no extrasolar planets to having too many to search. Narrowing the list of hopefuls requires looking at extrasolar planets in a new way.

But Tau Ceti already doesn't make the cut.

A new study provides a possible explanation of reports that mothers of twins are more likely to have smoked, despite evidence that nicotine reduces fertility.

Nicotine has an effect on hormone production, and while smoking may have deleterious effects on fertility, the study found that it may raise the likelihood of producing twins in women with certain genetic backgrounds. The researchers discovered significant interactions between smoking and variants in several genes, especially one in the TP53 gene.

Health food stores often regard science and evidence-based medicine as the tools of profiteering and greed so it is ironic that they continue to sell dietary supplements to children. Some even recommend them, despite clear warning labels that read "for adult use only."

Though supplements are an unregulated wild frontier at the US Food&Drug Administration level, body-shaping supplements are banned for sale to minors in 49 U.S. states. Nonetheless, 15-year-olds were able to buy them in health food stores across the country and the staff even recommended certain products that were illegal for sale to minors.

After performing thousands of unsuccessful experiments in his attempt to perfect the light bulb, Thomas Edison famously remarked: "I have not failed, not once. I've discovered ten thousand ways that don't work."

Australian leaders of an ongoing pancreatic cancer clinical trial known as the Individualised Molecular Pancreatic Cancer Therapy or 'IMPaCT' trial, can say exactly the same thing as Edison. In conventional terms, the trial has been a failure, because it has been unable to recruit eligible patients to-date, but that may lead to a new paradigm of personalized cancer care for pancreatic cancer and other aggressive cancer types. 

The discovery of a gene involved in determining the melting point of cocoa butter should lead to new varieties of the cocoa plant that could extend the climate and soil-nutrient range for growing the crop