- Patients enrolled on the phase II portion of the study will be required to have predominantly clear cell variant of renal cell carcinoma with less than 25% of any other histology (papillary or chromophobe or oncocytic); there must be histologic confirmation by treating center of either primary or metastatic lesion; patients must be willing to consent for obtaining tumor tissue blocks or unstained slides from prior biopsy or surgery; patients who participated in the Phase I part of the protocol will not be part of the accrual to the Phase II cohort