Dr. Kassim specializes in hematology and hematopoietic stem cell transplantation. His clinical research efforts is focused on harnessing the use of stem cell transplant technology in improving patient care outcomes, both for hematologic malignancies (such as leukemias, lymphomas and myelomas) as well as benign hematologic disorders such a sickle cell disease, aplastic anemias and bone marrow failure states.

He directs the adult sickle cell disease program, and in conjunction with the Department of Pediatrics at Vanderbilt Childrens Hospital and Meharry Medical Center, have helped develop a Sickle Cell Disease Center of Excellence to address the need of patients and families affected by the disorder. Research in the area of sickle cell disease focuses mainly on the study of epigenetic determinants of disease expression, development of a patient centered medical home model of care and use of evidence-based management paradigms to improve both patient satisfaction and care outcomes. He is investigating the use of alternate donor and reduced intensity hematopoietic stem cell transplant approaches as a curative modality for the disease.