Philip Leder

Philip Leder (born November 19, 1934 in Washington, D.C.; † February 2, 2020 in Chestnut Hill, Massachusetts) was a U.S. geneticist who was particularly interested in the genetic basis of cancer.

Leder studied at Harvard University, where he received his B.A. degree in 1956 and his M.D. degree from Harvard Medical School in 1960. After further medical training at the University of Minnesota, he went to the National Institutes of Health (NIH) in 1962, where his collaboration with Marshall Nirenberg occurred, and was at the Weizmann Institute in the mid-1960s. He then returned to NIH to conduct research, first in the Laboratory of Biochemistry at the National Cancer Institute and then as Director of Molecular Genetics at the National Institute of Child Health and Human Development (NICHD) beginning in 1972. He became a professor at Harvard in 1980, where he was the founding director of the Department of Genetics at Harvard Medical School. Leder directed the Harvard Institute of Human Genetics until 2003. He became the John Emory Andrus Professor of Genetics there. He was also a senior investigator at the Howard Hughes Medical Institute for two decades.

Leder is known for fundamental work in molecular biology and genetics, particularly the classic 1964 experiment with Marshall Nirenberg that further substantiated the triplet structure of the genetic code and provided the remaining components of the code that could not be determined by the previous poly-U experiment of Nirenberg and Heinrich Matthaei (1961).

Together with colleagues, he developed the first recombinant DNA vector system (based on phages) that met specified safety standards. With this system, he and colleagues cloned the gene for globin and investigated its gene regulation.

Leder also studied the genetic basis of the diversity of antibodies produced by B cells (via systematic rearrangement of the two genes encoding the antibody light chains) and the role of genetic rearrangements in carcinogenesis. For example, he showed that in a malignant tumor of B cells (Burkitt's lymphoma), the c-myc gene, which normally plays a role in cell division, is located on a different chromosome (near an antibody gene) instead of in its normal position on chromosome 8.

He inserted a c-myc gene reduced by its control sequences into mouse embryo cells and was thus able to generate transgenic mouse strains that were more susceptible to cancer. This proved that altering the control sequences of a gene could cause cancer. For this and similar mice (OncoMouse), which Leder developed from the early 1980s, he obtained a patent on behalf of Harvard University. In 1988, together with Timothy Stewart, he obtained the first patent in the USA (in the name of Harvard) for a genetically modified animal, the concept of the cancer mouse (OncoMouse), a transgenic mouse that is particularly susceptible to cancer by manipulating different oncogenes. The patent is even broader, covering all animals except humans. In Europe, the patent was granted in 1992 after initially being rejected, but after a lengthy legal battle it was rejected on formal grounds in 2006.

Leder also investigated the interaction of oncogenes and, most recently, the metabolism of tumour cells (correlation of oxygen supply and glycolysis) with possible approaches for cancer therapy.

Leder received the Detur Award at Harvard while still an undergraduate. He was awarded the Robert Koch Medal in 2008 and the Albert Lasker Award for Basic Medical Research in 1987. He received the Dickson Prize in Medicine and the Richard Lounsbery Award in 1981, the Genetics Society of America Medal in 1985, the National Medal of Science in 1989, the H.P. Heineken Prize in Biochemistry and Biophysics from the Netherlands Academy of Sciences in 1990, and the William Allan Award in 1997. Leder was a member of the National Academy of Sciences, the American Academy of Arts and Sciences, and the American Association for the Advancement of Science. He was a four-time honorary doctor (2010), including from Yale University. In November 2015, he received an honorary doctorate for his life's work from the Medical Faculty of the University of Basel.