Dr. Peter Dirks is a professor of neurosurgery and molecular genetics at the University of Toronto and a senior scientist in the Developmental and Stem Cell Biology Program at the Hospital for Sick Children. His research focus is on the biology of brain tumours of children and adults, with a primary aim to understand how the molecular programs in normal neural stem cells become perturbed to cause and sustain the growth of these hard-to-treat cancers. In addition, he is interested in brain tumour heterogeneity and how the diverse cell types that comprise these tumours contribute to tumour maintenance and therapeutic resistance.
Dr. Peter Dirks graduated from Queen’s University Medical School in Kingston, Ontario in 1989. Then, he completed his PhD in Molecular and Cellular Pathology in 1997 at the University of Toronto, his neurosurgery training at the University of Toronto in 1998 (Fellow of the Royal College of Surgeons, Canada, 1998) and his Paediatric Neurosurgery Fellowship training at L’hôpital Necker Enfants Malades (Paris) in 1998.
Dirks was appointed to Neurosurgical Staff at The Hospital for Sick Children (SickKids) and the University of Toronto in 1998 and appointed to the SickKids Research Institute’s Developmental & Stem Cell Biology Program in 1999. He established his research laboratory to study brain tumours in the Arthur and Sonia Labatt Brain Tumour Research Centre at SickKids in 1999.
His group was the first prospectively identified cancer stem cells (CSCs) in human brain tumours (Nature 2004), the second such description in a solid human cancer. They subsequently identified new methods for culturing patient-derived glioblastoma (GBM) stem cells (Cell Stem Cell 2009), which directly led to chemical and genetic screening capacities. Recently they have used single cell cloning approaches with human GBM to understand the functional and genetic heterogeneity at a single clone level (PNAS 2015). They have also identified CSCs in brain tumours arising in genetically engineered mice (Cancer Res. 2009), particularly using lineage tracing approaches (Cancer Cell 2014), which point to rare quiescent and treatment resistant stem cells at the apex of the cancer hierarchy. Together with collaborators, they published one of the first chemical biology screens on normal neural stem cells (Nature Chem. Biol 2007), unexpectedly uncovering hits in neurotransmission pathways, which led to a recent discovery that blocking dopamine signalling through its DRD4 receptor could be a neurochemical strategy for GBM treatment (Cancer Cell, 2016).
More recently, they have shown that increasing ASCL1 levels in GBM stem cells can restore neuronal lineage potential and can promote terminal differentiation (Cell Stem Cell 2017). Directing GSCs toward terminal differentiation may provide therapeutic applications for a subset of GBM patients and strongly supports efforts to restore differentiation potential in GBM. Finally, in a study of the clonal dynamics of barcoded fresh primary GBM cells, they showed that tumours of diverse genetic background follow a similar growth program that resembles a developmental hierarchy, suggesting that therapies that exploit cell programs may be applicable to tumours of diverse genotypes (Nature 2017).
His clinical interests lie with the entire spectrum of paediatric neurosurgical practice, with emphasis on the surgical treatment of childhood brain tumours and brain vascular malformations.