WASHINGTON, Oct. 5 (Xinhua) -- Elizabeth H. Blackburn, Carol W. Greider and Jack W. Szostak, all from the United States, won the Nobel Prize for Medicine for 2009 on Monday.

    The trio were awarded the prize for the discovery of "how chromosomes are protected by telomeres and the enzyme telomerase," the Nobel jury made the announcement at a press conference at Karolinska Institute in Stockholm.

    The prize-winners' work, done in the late 1970s and 1980s, set the stage for research suggesting that cancer cells use telomerase to sustain their uncontrolled growth. Scientists are studying whether drugs that block the enzyme can fight the disease.

    "Dr. Blackburn's research over the course of more than three decades has revolutionized scientists' understanding of the way in which cells function," University of California, San Francisco Chancellor Susan Desmond-Hellmann said Monday in a press release.

    "Her co-discovery of the telomerase has revealed a mechanism that plays a key role in determining the lifespan of cells, as well as the processes of cell aging and cancers."

    "Her generous spirit, curiosity and highly collaborative nature have led her to forge research partnerships that have significantly broadened scientists' capacity to understand the remarkable telomerase enzyme. As a scientist, a colleague, a mentor and a woman in science, she is an inspiration to the nation and the world."

    University of California President Mark Yudof also commended the work of Blackburn. "The entire University of California community could not be more proud of Dr. Elizabeth Blackburn. Her path breaking work is yet another reminder of the life-changing contributions UC makes to California and to the world, " he said.

    "This is a wonderful moment, not only for Dr. Greider but also for all of us here at Johns Hopkins who share in her passion for discovery and her zeal for putting knowledge to work for the good of humanity," Johns Hopkins University President Ron Daniels said.

    "We are thrilled by this magnificent accomplishment of Carol and her colleagues and even more so by the implications of her continuing work for our understanding of such complex problems as cancer and aging. Carol has advanced scientific knowledge immeasurably, but she remains unsatisfied and wants to know more. That is the Johns Hopkins way."

    A delighted Greider thanked the Nobel Foundation for the award and emphasized that the recognition highlights the value of "discoveries driven by pure curiosity. We had no idea when we started this work that telomerase would be involved in cancer, but were simply curious about how chromosomes stayed intact."

    "What intrigues basic scientists like me is that any time we do a series of experiments, there are going to be three or four new questions that come up when you think you've answered one. Our approach shows that while you can do research that tries to answer specific questions about a disease, you can also just follow your nose."

    Working with a single-celled, pond-dwelling organism called Tetrahymena, Greider said in a press release that these organisms -- rather than primates or humans -- were the best test system because Tetrahymena contain "more like 40,000 chromosomes, compared to our 23 pairs" and thus have far more chromosome ends to study.

    "The most far-reaching discoveries are the product of basic research," said Stephen Desiderio, director of the Institute for Basic Biomedical Sciences at Johns Hopkins. "We are thrilled that Carol is being recognized for her work, which reminds us that science is most powerful when it is driven by curiosity."