This year's Nobel prize for physiology or medicine has been awarded to three American scientists-Elizabeth Blackburn, Jack Szostak and Carol Greider . The trio with their work in the late 1970's and 80's opened new avenues of research for anti-cancer drugs and therapies.                They discovered that the chromosomes, the thread like structures in human cells are protected by telomeres - the portion at the chromosome ends.            The telomeres- the portions marked red at the chromosome ends add new DNA, the genetic material,  whenever any erosion of DNA takes place during metabolism.  Elizabeth Blackburn compared telomeres to the tips on the ends of shoelaces that keep them from fraying. An enzyme telomerase is involved in this process. When people begin to age, the telomere region keeps shortening bringing about the gradual erosion of the genetic material and thus, age related problems.         In cancer cells, a high quantity of the telomerase enzyme has been found. Thus these tumor cells use the regenerating power of this enzyme to grow in an uncontrolled manner spreading throughout the body .       This discovery of telomeres and telomerase has laid the foundation for therapies and drugs which target the telomerase enzyme in cancer cells thus controlling cell growth.