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About Sickkids
About SickKids

Bret Pearson, PhD

Research Institute
Senior Scientist
Developmental & Stem Cell Biology

University of Toronto
Associate Professor
Department of Molecular Genetics

Other Positions
Ontario Institute for Cancer Research (OICR)
New Investigator

Phone: 416-813-7654 ext. 328370
Fax: 416-813-8456

For more information, visit:

Pearson lab website

Brief Biography

May 2010 to present
Scientist – Developmental & Stem Cell Biology Program, The Hospital For Sick Children.
Investigator – Ontario Institute for Cancer Research, Cancer Stem Cell Program, Toronto, Ontario, Canada
Adult stem cells and tumorigenesis in Planarians

May 2005 to May 2010
Postdoctoral Fellow
Advisor:  Dr. Alejandro Sánchez Alvarado

Howard Hughes Medical Institute
Department of Neurobiology and Anatomy
University of Utah, Salt Lake City, UT
Adult stem cells and tumorigenesis in Planarians

August 1999 to May 2005
Graduate Student
Advisor:  Dr. Chris Q. Doe

Howard Hughes Medical Institute
Institutes of Molecular Biology and Neuroscience
University of Oregon, Eugene, OR
Temporal identity in Drosophila neuroblast lineages

May 1998 to August 1999
Laboratory Technician
Advisor:  Dr. Nansi Jo Colley

Department of Opthalmology
University of Wisconsin-Madison
Potassium-dependent sodium/calcium exchangers in Drosophila development

May 1997 to May 1998
Undergraduate Research
Advisor:  Dr. Sean B. Carroll

Howard Hughes Medical Institute
Department of Genetics
University of Wisconsin-Madison
Evolution of butterfly wingspot patterns

Research Interests

The main focus in our lab is to understand how adult stem cells make their correct cellular lineage in space and time to replace the exact number and type of cells lost to physiological turnover (homeostasis) or injury (regeneration). Planarians offer a unique system to study stem cell lineage production in adult animals in vivo.

External Funding

New Investigator Award - Ontario Institute for Cancer Research (OICR) 


  • 2006 - Damon Runyon Image Contest
  • 2006 - Larry Sandler Graduate Thesis Award Runner Up
  • 2005 - Harold M. Weintraub Graduate Research Award (Given by Fred Hutchinson Cancer Research Center)


Currie KW, Pearson BJ. (2013) Transcription factors lhx1/5-1 and pitx are required for the maintenance and regeneration of serotonergic neurons in planarians. Development. 140(17):3577-88.

Zhu SJ, Pearson BJ. (2013) The retinoblastoma pathway regulates stem cell proliferation in freshwater planarians. Developmental Biology. 373(2):442-52.

Labbé RM, Irimia M, Currie KW, Lin A, Zhu SJ, Brown DD, Ross EJ, Voisin V, Bader GD, Blencowe BJ, Pearson BJ. (2012) A comparative transcriptomic analysis reveals conserved features of stem cell pluripotency in planarians and mammals.  Stem Cells. 8:1734-45.

Bocchinfuso DG, Taylor P, Ross E, Ignatchenko A, Ignatchenko V, Kislinger T, Pearson BJ, Moran MF. (2012) Proteomic profiling of the planarian Schmidtea mediterranea and its mucous reveals similarities with human secretions and those predicted for parasitic flatworms.  Molecular Cell Proteomics. 9:681-691. 

Tu KC, Pearson BJ, Sánchez Alvarado A. (2012) TORC1 is required to balance cell proliferation and cell death in planarians. Developmental Biology. 365(2): 458-469.

Pearson BJ, Sánchez Alvarado A. (2010) A planarian p53 homolog regulates proliferation and self-renewal in adult stem cell lineages. Development. 137:213-221.

Pearson BJ, Eisenhoffer GT, Gurley KA, Rink JC, Miller DE, Sánchez Alvarado A. (2009) A Formaldehyde-based whole-mount in situ hybridization method for planarians. Developmental Dynamics. 238:443-450.

Pearson BJ, Sánchez Alvarado A. (2009) Regeneration, stem cells and the evolution of tumor suppression. Cold Spring Harbor Annual Symposium. Volume 73, Control and Regulation of Stem Cells.

Oviedo NJ, Pearson BJ, Levin M, Sánchez Alvarado, A. (2008) Planarian PTEN homologs regulate stem cells and regeneration through TOR signaling. Disease Models and Mechanisms. 1:131-143.

Ochi H, Pearson BJ, Chuang P-T, Hammerschmidt M, Westerfield M. (2006) Hhip regulates zebrafish muscle development by both sequestering hedgehog and modulating localization of smoothened. Developmental Biology. 297:127-140.

Grosskortenhaus R, Pearson BJ, Marusich A, Doe CQ. (2005) Regulation of temporal identity transitions in Drosophila neuroblast lineages. Developmental Cell. 8(2):193-202.

Pearson BJ, Doe CQ. (2004) Specification of temporal identity in the developing nervous system. Annual Review of Cell & Developmental Biology. 20:619-647.

Pearson BJ, Doe CQ. (2003) Regulation of neuroblast competence in Drosophila. Nature. 425:624-628.

Isshiki T, Pearson BJ, Holbrook S, Doe CQ. (2001) Drosophila neuroblasts sequentially express transcription factors which specify the temporal identity of their neuronal progeny. Cell. 106:511-521.

Pierce-Shimomura JT, Faumont Serge, Gaston MR, Pearson BJ, Lockery SR. (2001) The homeobox gene lim-6 is required for distinct chemosensory representations in C. elegans. Nature. 410:694-698.