Prospective Validation of Circulating Tumor Cells & Circulating Endothelial Cells as Biomarkers in Renal Cancer

Circulating tumor cells (CTCs) have prognostic value in several tumor types, and increasing evidence suggests that molecular characterization of CTCs can serve as a "liquid biopsy" to understand and address treatment resistance. The goal of this proposal is to demonstrate that CTCs can be accurately enumerated and characterized in metastatic clear cell renal cancer (CCRC) and can serve as prognostic/predictive biomarkers to improve treatment. The challenge surrounding CTC analysis in CCRC is that most CTC technologies (including the clinical gold-standard CellSearch®) depend in epithelial markers such as EpCAM that are expressed at low or heterogeneous levels in CCRC. Members of the research team have developed a novel CTC microfluidic technology that can effectively detect CTCs that are completely undetectable by CellSearch® because of very low EpCAM expression, as well as allowing for CTC recovery for downstream molecular characterization. The goal of this proposal is therefore to test the hypotheses that (1) The microfluidics CTC technology will have better sensitivity/specificity relative to the CellSearch in metastatic CCRC; and (2) Enumeration of CTCs in metastatic CCRC patients (n=66) will have prognostic value, while molecular characterization of CTCs for expression of biomarkers (VHL, VEGF, mTOR, HIF1/HIF2, AKT) related to CCRC etiology will be predictive of response/resistance to targeted therapies. Although CCRC is relatively uncommon, the lack of established adjuvant treatments and high cost of targeted therapies in the palliative setting makes the search for new prognostic/predictive biomarkers an important clinical goal.