Circulating Tumors Cells and Circulating Endothelial Cells in Renal Cell Carcinoma

Circulating tumors cells (CTCs) and circulating endothelial cells (CECs) are found in the
peripheral blood of most common malignancies and are promising surrogate biomarkers. The
CellSearchTM CTC assay is currently approved by the Food and Drug Administration as an
adjunct for monitoring disease status in breast, prostate and colon carcinomas; and evidence
in breast cancer suggests that CTCs are an independent predictor of overall survival and
progression-free survival. Evolving data demonstrates a potential role of CTCs as a
surrogate assessment for treatment response. The benefit of this approach in renal cell
cancer(RCC) is unknown and further investigation is needed to determine the feasibility of
using the CellSearchTM CTC Assay in this malignancy.

Circulating endothelial cells (CECs) are increased in the peripheral blood of cancer
patients and appear to be a marker of tumor related angiogenesis. Studies suggest that CECs
increase in the setting of progressive disease and decrease in response to treatment with an
antiangiogenic agent. Although current data evaluating CECs in RCC is limited, there is
significant interest in CEC evaluation as a marker of treatment response given the majority
of current FDA approved RCC therapies target tumor angiogenesis.

The overall objective of this protocol is to obtain preliminary data and experience using
our Cell Search Assay system which can be used for future grant applications. Our
hypothesis is that CTCs and/or CECs will be valuable and versatile biomarkers for
therapeutic response, determination of relapse and survival in patients with renal cell
cancer.