A Cancer Pioneer

When Prof. Leo Sachs was young, he dreamed of founding a kibbutz in Israel and even spent two years as a farm laborer to prepare for pioneering on the land. Today, however, Prof. Sachs of the Institute's Molecular Genetics Department is renowned for pioneering of a very different nature.

One of the world's leading scientists in the areas of cell biology and cancer research, Sachs has made fundamental contributions to his field and paved the way for successful clinical treatments.

A recent recognition of his achievements came from Harvard Medical School, which presented him with its Warren Alpert Foundation Prize in April of this year. This is but the latest in a long list of prizes that have punctuated the illustrious career of the 6'8" researcher, who is quippingly said to be "head and shoulders" above many of his colleagues.

At the very beginning of his scientific career in Israel, Sachs had an idea that ultimately made it possible to diagnose human diseases in the womb. The year was 1952, and the German-born Sachs, who had been educated in England, had just moved to the new Jewish state where he was recruited by the Weizmann Institute. He started working on a theory that human amniotic fluid, which bathes the baby in the womb, contains fetal cells that can provide information about the fetus. His studies proved him right. He showed that cells in the fluid can be reliably used to tell the sex of the baby before birth and also reveal other important properties of the fetus. This groundbreaking research formed the basis for today's widely used prenatal diagnosis by amniocentesis.

Sachs subsequently developed the first ever procedure to grow, clone and induce the development of different types of normal blood cells in a petri dish. Using this process he discovered and identified a family of proteins, among them colony-stimulating factors and some interleukins, that control blood cell production in its various stages.

One of the proteins that Sachs identified, the granulocyte colony-stimulating factor, is now used clinically to boost the production of disease-fighting white blood cells in cancer patients undergoing chemotherapy or irradiation. The same protein was also found to help improve the success of bone marrow and blood cell transplants, as well as a number of other clinical procedures.

Sachs also asked the question: what changes in normal development result in leukemia, and can this process be reversed? He later demonstrated that the proteins he had initially discovered, and some other compounds, can induce certain leukemic cells to behave again like normal ones both in a petri dish and in the body. Until then, most scientists had believed that malignancy was irreversible.

Sachs is now studying the genetic changes which take place in leukemic cells, enabling them to live longer, and looking for ways to "switch off" these life-maintaining genes in the cancer cells so that they die like normal cells that the body no longer needs. This research could provide another new approach to cancer treatment.

Contemplating 45 years of work, Sach says: "There have been ups and downs. But overall I'm optimistic and believe that all problems have solutions. One has to be permanently curious and keep on trying."