Initially a student of English literature and then trained as a physician, Dr Varmus began his scientific career as a member of the US Public Health Service at the National Institutes of Health in the late 1960s, working on gene regulation in bacteria with Ira Pastan. Then, during twenty-three years at the University of California Medical School in San Francisco, working in extensive partnership with J. Michael Bishop, their trainees and Dr Varmus studied many aspects of the biology of retroviruses, including the mechanism of viral DNA synthesis and integration, gene expression, viral entry, and oncogenesis in vivo and in vitro.
The cancer-causing potential of retroviruses led to the identification of the first and several other cellular proto-oncogenes, both by tracing viral oncogenes to their cellular progenitors and by identifying cellular genes transcriptionally activated by proviral insertion mutations. These genes and others encoding members of cell signalling pathways have often been found mutated in human tumours and are targets for development of novel and effective therapies. For this work, Dr Bishop and Dr Varmus shared a Nobel Prize for Physiology or Medicine in 1989.
Dr Varmus has also taken on significant administrative roles during the past twenty-three years: as Director of the NIH from 1993 to 1999, as President of Memorial Sloan Kettering Cancer Center from 2000 to 2010, and as Director of the National Cancer Institute from 2010 until April, 2015, when he became the Lewis Thomas University Professor at Weill Cornell Medicine. He is also a Senior Associate Member of the New York Genome Center.