Studies in our lab are aimed at defining biological markers that shed light on the pathogenesis and/or aid in the therapeutic stratification of pediatric renal tumors and pediatric germ cell tumors. We are performing these studies in collaboration with the Children’s Oncology Group (COG), which governs treatment protocols used for over 90% of pediatric malignancies and serves as a central collections agency for biological samples.
Pediatric renal tumors fall into four primary categories: Wilms Tumors (WT, 85%), Clear Cell Sarcomas of the Kidney (CCSK, 5%), Congenital Mesoblastic Nephromas (CMN, 4%), and Rhabdoid Tumors of the Kidney (RTK, 3%). While the majority of WTs are easily recognized by their characteristic combination of epithelial, blastemal and stromal elements, approximately 5% of WT are composed exclusively of undifferentiated blastemal or stromal elements. Such tumors are easily mistaken for CCSK, CMN and RTK. It has been the experience of the COG Renal Tumor Pathology Center that approximately 25% of such lesions are misdiagnosed by the local pathologist. Even following central pathology review, a small but significant number of tumors are provided a diagnosis that is less than fully certain. The importance of an accurate diagnosis is most evident when the differences in therapy and prognosis between these four different tumors are considered. Our goal has been to utilize gene expression data to accurately and reliably distinguish CCSK, CMN, RTK and WT, and to define diagnostically useful gene expression signatures for each of these entities.
In collaboration with Dr. Spencer Huang (http://www.preventivemedicine.northwestern.edu/huang.htm ) a biostatistician and faculty member in the Department of Preventative Medicine at Northwestern University's Feinberg School of Medicine, we have developed a classifier which accurately predicts the category of pediatric renal tumors.
In a recently accepted manuscript to Clinical Cancer Research, we report findings on CCSKs. CCSK are the second most common pediatric renal tumor. The molecular and cellular pathobiology of these tumors has remained elusive, and there are no positive diagnostic markers. Utilizing microarray analysis followed by protein verification, we present novel findings that neural markers are upregulated in CCSK, and that the sonic hedgehog and AKT pathways are activated. Potential therapeutic targets are also identified. This work suggests mechanisms for proliferation in CCSK and identifies a potential link between neuroectodermal tumors and CCSK. Below is a link to supplemental data for this work: