Prof Szer has particular expertise in malignant haematology and haemopoietic stem cell transplantation, which he established as a form of therapy in Victoria in the early 1980s. He is a recognised key opinion leader in the rare non-malignant disorders paroxysmal nocturnal haemoglobinuria and Gaucher disease. He is a member of the Medical and Scientific Advisory Group of Myeloma Australia and is immediate past President of the Worldwide Network for Blood and Marrow Transplantation and current President of the World Marrow Donor Association. He has been Director of the Western and Central Melbourne Integrated Cancer Service since 2009. He has also been Editor in Chief of Internal Medicine Journal since 2005 and is on the editorial board of several other international journals.