PROJECT SUMMARY/ABSTRACT
Osteosarcoma, the most common primary tumor of bone, primarily affects children, adolescents, and young
adults. A diagnosis of osteosarcoma is devastating, as approximately half of pediatric osteosarcoma patients
experience metastasis and ultimately succumb to the disease within 10 years of their diagnosis. Currently
there is no diagnostic test to predict prognosis, so all patients are treated with aggressive surgery and intense
chemotherapy with high rates of toxicity. However, a subset of patients may not require as aggressive therapy
to achieve remission. Additionally, those that survive have a high incidence of lifelong morbidities, including
treatment-related secondary malignancies. Accurate prognostic indicators could be integrated into the standard
of care for osteosarcoma to guide therapy. Children with more favorable prognoses could be treated more
conservatively, reducing the need for aggressive surgery, and decreasing the intensity of systemic therapy.
This would decrease the likelihood and severity of long-term morbidities, and reduce the probability of
secondary, treatment-related malignancies without negatively affecting prognosis. Conversely, patients with a
worse prognosis could receive more aggressive treatments or be guided to experimental clinical trials to
improve their long-term survival. In this project, we will develop a serum exosomal gene signature associated
with prognosis in pediatric osteosarcoma. Exosomes are membrane-bound microvesicles containing cargo
associated with tumor biology and disease state. We will first identify biomarkers by sequencing serum
exosomes from a large cohort of pediatric osteosarcoma patients with known clinical outcomes. We will then
identify genes associated with metastatic propensity using xenograft mouse models established from pediatric
osteosarcomas with distinct biologic behavior. We will analyze co-regulated gene clusters and apply machine
learning, improving sensitivity and specificity, and ultimately resulting in a more robust gene signature. The
osteosarcoma gene signature developed in this project can be utilized in the clinical setting to predict
prognosis, stratifying patients into more appropriate treatment categories, and having the potential to improve
management of this devastating disease. Additionally, these biomarkers will contribute to our understanding of
the biological behavior and progression of osteosarcoma, allowing us to infer mechanisms of host response,
metastasis, and response to therapy. Importantly, this K01 is critical to advancing my career as a translational
scientist by providing the necessary protected time and dedicated resources to perform high-quality, clinically
relevant research, under the guidance of an exceptional multidisciplinary mentor team. This award will facilitate
my transition to independence, as the data procured in this project will allow me to be competitive for future
independent funding applications. Additionally, as I complete these aims, I will develop the necessary
knowledge and leadership skills of a successful independent research scientist specializing in exosome biology
and translational models of pediatric osteosarcoma and ultimately expanding to other cancers.