Professor Mak is internationally known for his work in the molecular biology of cancer and the immune system. He is a professor in the Department of Medical Biophysics and the Department of Immunology at University of Toronto; the Director of the Campbell Family Institute for Breast Cancer Research at the Princess Margaret Cancer Centre; and a senior scientist at the Ontario Cancer Institute. Mak is a world leader in the genetics of immunology and cancer. In 1984, he led the group that discovered the T cell receptor, and his published work on the cloning of T cell antigen receptor genes has been cited over 1,200 times. Since this landmark discovery, Mak has focused on elucidating the mechanisms underlying immune responses and tumorigenesis.

He pioneered the use of genetically engineered mouse strains to identify genetic susceptibility factors associated with various immune disorders or different types of cancer. In particular, his team discovered that CTLA4 is a negative regulator of T cell activation (cited 2,000 times), paving the way for the development of anti-CTLA4 agents now in clinical use for autoimmune diseases.

Mak’s lab also made major contributions to defining the functions of PTEN (cited more than 2,000 times) as well as the relationship between the breast cancer susceptibility genes BRCA1 and BRCA2 and defects in DNA repair. Most recently, Mak’s studies of the functions of various gene products in normal and cancerous cells have yielded important information on their biology that is crucial for the identification of new drug targets and the development of more effective cancer therapies.

Mak was named an Officer of the Order of Canada in 2000 and was ranked #9 among The Best Scientists for 2023. Together with HKU, he has experience hosting an extremely successful CSC in the past for immunology and has attracted international recognition.