Yoon-Jae Cho, or Jae, grew up near Pittsburgh, where his father practices Geriatric Medicine in the coal mining towns of western Pennsylvania. His mother, an artist by training, kept a studio where he and his sisters spent hours creating, in his words, “oddly shaped coffee mugs and bad art,” providing a source of creativity for his subsequent work in science and medicine. An avid athlete, he competed in swimming and rowing in high school and college, and became a highly competitive cyclist while in medical school. His fearlessness is evident in later activities including summit ski descents from Mt. Hood, Mt. St. Helens, Mt. Adams and portions of Mt. Rainier, and an extensive surfing resume including Panama, Costa Rica, Puerto Rico, Hawaii, California, Oregon, Washington State, British Columbia, New Hampshire and Rhode Island.
Jae completed his undergraduate studies at Rice University in 1993, obtaining degrees in both Chemistry and Anthropology in three years. Immediately drawn to the lab, he worked successively with Kevin Burgess (chemical synthesis of RNA analogs), Alan Wu (mass spec of cannabinoids), and George Schroepfer (chemical synthesis of sterol and cholesterol derivatives) during his undergraduate years. In between undergraduate and medical school, he worked for a year in the lab of Madeleine Duvic at MD Anderson Cancer Center and the University of Texas. In the Duvic lab, he cloned and sequenced the first flotillin and investigated HIV-associated psoriasis.
Jae then moved to the Oregon health & Science University, from which he received his M.D. in 2002. At Oregon, he worked with Bill Horton at the Shriners hospital Research Center and with Brian Druker, focusing on the role of FGFR3 in skeletal development and dysplasia. His work in the Horton lab was outstanding. Initially, he contributed to a project published in Nature that discovered STAT1 to be involved in FGFR3 induction of p21 expression in chondrocyte proliferation regulation. He subsequently demonstrated that activating mutations in FGFR3, associated with skeletal dysplasias, resulted in substantially altered levels of ubiquitination which affected the trafficking of internalized receptors to favor recycling over degradation. From this work he introduced a novel model of chondrodysplasia based on alteration of chondrocyte survival and differentiation through enhanced recycling of mutant activated receptors. This work led to co-authorship on three additional publications in excellent journals. He was first author on two major papers that were published in PNAS and American Journal of Medical Genetics. His mentors, Bill Horton and Brian Druker, both comment on his work ethic and independence, and note him to be an exceptionally warm and personable in the lab and in clinical settings.
After pediatric residency in Oakland, California, he moved to Boston for child neurology residency at Children’s hospital and neuro-oncology fellowship at Children’s and the Dana-Farber Cancer Institute. Working in the lab of Scott Pomeroy he continued to be highly productive, completing a ground breaking genomic analysis of medulloblastoma which has redefined the way we look at these tumors. This work is the largest genomic study of medulloblastoma to date involving the analysis of the mRNA and miRNA transcriptome and high-resolution copy number data of over two hundred primary medulloblastoma samples. Jae’s analysis, published in Journal of Clinical Oncology, was a truly integrated and detailed molecular study of this disease, showing that medulloblastomas are comprised of at least four subtypes that have distinct transcriptomes and genetic abnormalities and that differ in their response to therapy and clinical outcomes. The clinical implications are highly significant. In a second high-profile paper in JCO, the limitation of ‘global’ markers as predictors of outcome in medulloblastoma was found to be due to the molecular heterogeneity inherent in this disease. To overcome this limitation, Jae helped develop an algorithm that integrated molecular subtyping into medulloblastoma risk-stratification, greatly enhancing our ability to accurately predict outcome for patients diagnosed with medulloblastoma. Genome-wide sequencing of individual genes, published in Nature, revealed that somatic mutations occur relatively infrequently in medulloblastomas compared to other cancers. Specific mutations were found to be associated with each medulloblastoma subtype, providing further insights into the mechanisms of tumorigenesis and new targets for biologically based small molecule therapies.
Beyond these studies in genomics and computational biology, Jae probed the role of microRNA dysregulation in medulloblastoma and cancer pathogenesis in general. He established a novel and critical link between miR-34a, MAGE and p53 in medulloblastoma, published in Neuro-oncology. Although MAGE-A was previously shown to regulate p53 at the transcriptional (methylation and histone acetylation) and post-translational (acetylation) level, he found miR-34a is linked to the epigenetic regulation of p53 via direct targeting of MAGE. This study revealed a previously unreported positive feedback mechanism in which p53 transcriptionally activates miR-34a which then directly targets MAGE-A genes, resulting in the consequent derepression of p53. This mechanism serves to “amplify” miR-34a’s own transcription, allowing for an “all or none” commitment to proliferative arrest and/or cell death. The end result in medulloblastoma cells is the modulation of responsiveness to chemotherapeutic agents.
As a testament to his collaborative spirit, during his tenure in Boston Jae had many productive collaborations including one with Charlie Robert’s lab at Dana-Farber Cancer Institute in understanding the basic pathogenetic mechanisms resulting from SMARRCB1 loss in atypical teratoid rhabdoid tumors (ATRT). His genomic analysis of primary ATRTs led to several publications with Charlie’s lab, including a Cancer Cell paper describing the antagonistic interaction between the polycomb repressive group proteins and the SWI/SNF chromatin remodeling complex and a Nature Medicine paper reporting activation of the Shh-GLI pathway through loss of SMARCB1.
In the fall of 2011, Jae moved to Stanford to establish his own laboratory, where he continues to study the molecular and cellular basis of medulloblastomas and other cancers. He is a regular participant in national and international forums, including the Children’s Oncology Group (COG) where components of this risk-stratification algorithm are currently being considered for implementation into the next generation of COG clinical trials. He also serves as co-leader of the committee to develop new therapies in COG. He lives with his wife Krysta Schlis, a Pediatric Oncologist at Stanford, and three small children, including twins, in Palo Alto. Despite the challenges of work and demands of his growing family, Jae still occasionally finds time to cruise along the California coast on his bike looking for the perfect place to surf.