enzyme reverse transcriptase. Temin would be one of his mentors that shaped his way of thinking, encouraging him to delve into diverse disciplines. During the early 1980s in Toronto, with his newly setup group, Mak was working on virology. Mak employed a technique called molecular subtraction, used by virologists, to attempt to identify the T-cell receptor, which was so elusive at the time it was referred to as the "Holy Grail of Immunology." In 1984, Mak discovered the T-cell receptor, with Mark M. Davis identifying the receptor in mouse. This work on the cloning of T-cell receptor genes, , has been cited nearly 1200 times. In spite of offers from prestigious institutions around the world, Mak remained committed to Canada's scientific community. In 1993, Mak received support from the world's largest independent biotech company, Amgen, to establish the Amgen Research Institute in Toronto. Financial support from Amgen resulted in his lab pioneering the use of knockout mice, and as a result his lab generated one of the first knockout mice and has generated more knockout mice than any other lab in the world. Mak's role in advancing the use of genetically altered mice in scientific study has led to important breakthroughs in immunology and understanding cancer at the cellular level. As of 2005, Amgen-produced papers have been cited more than 40,000 times. The basic research in cancer conducted by Mak has been published in top international scientific journals and he has given several keynote addresses at cancer symposia across Canada and the United States. By 1995, Mak had reached a high point in his career, when he and his team published their seminal findings on the function of CTLA-4, thus paving the road for Immunotherapy and Checkpoint inhibition as potential anti-cancer therapies. In 2004 Mak became the director of the Advanced Medical Discovery Institute and the Campbell Family Institute for Breast Cancer Research. He is also the senior scientist, division of Stem Cell and Developmental Biology, Advanced Medical Discovery Institute/Ontario Cancer Institute. He is a member of the Cancer Research Institute Scientific Advisory Council. Since 1984, he has been a Professor in the Departments of Medical Biophysics and Immunology at the University of Toronto. From the early 2000s, Mak concentrated his efforts on the emerging field of cancer metabolism. Mak, Lewis C. Cantley, and Craig B. Thompson together founded Agios Pharmaceuticals, a biotech pharmaceutical company whose sole purpose is to