Science  05 Apr 2013:
Vol. 340, Issue 6128, pp. 16
  1. Hormone Therapy Breast Cancers Equally Virulent

    Breast cancers linked to hormone replacement therapy (HRT) are no less deadly than those that strike women who are not taking hormones, a new study suggests. Published last week in the Journal of the National Cancer Institute, the study tackles a long-standing controversy: whether breast cancers associated with HRT are less likely to kill.

    In 2002, the Women's Health Initiative reported that results from a clinical trial showed that women on hormones who were diagnosed with breast cancer were at least as likely to die as those who got breast cancer while taking placebos. But observational studies suggested the opposite—that HRT-associated breast cancers have a better prognosis.

    Rowan Chlebowski, a breast oncologist at Harbor-University of California, Los Angeles, Medical Center, and his colleagues tried to bridge that gap by studying more than 40,000 women who were part of a different effort, the Women's Health Initiative Observational Study. The team found that survival after a breast cancer diagnosis was virtually the same in those who took hormones and those who didn't. But this, too, is unlikely to be the last word. One lingering question is whether there are differences in the biology of tumors that show up in women taking hormones.

  2. Sorting Through the Bits and Pieces of Plate Tectonics


    Geologists long ago realized that slices of rock plastered onto North America—from southern Alaska to Nevada to western Mexico—are actually well-traveled terranes that began their geologic lives hundreds of millions of years ago as distant volcanic archipelagoes. But, using the latest seismic probings of the deep interior, researchers are finding that the plate tectonic workings that delivered North America's exotic terranes didn't operate the way they thought.

    Great slabs of ocean tectonic plate were once thought to deliver the crustal scraps to North America before sinking into the depths. But the positions and orientations of those slabs, now thousands of kilometers below Earth's surface, do not jibe with that paradigm, say seismologist Karin Sigloch of Ludwig Maximilians University in Munich, Germany, and geologist Mitchell Mihalynuk of the British Columbia Geological Survey in Victoria, Canada, in this week's issue of Nature.

    Instead of the eastward-moving Farallon plate—now disappearing beneath the Pacific Northwest—delivering terranes to the continent, a westward-roaming North America must have plowed into them where they stood, building out the continent and driving up mountains along 6000 kilometers of North America.

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