IL2 and metastatic neoplasm: Approximately 30% of patients present with metastatic disease (mRCC), often associated with poor prognosis and subsequent 5-year survival rate [2,3] Until recently, treatment was limited to cytokine therapies (interleukin-2 [IL-2] and interferon-alfa [IFN-α ]) that produce modest response rates (< 20%) and substantial toxicities, although occasional complete responses have been reported [4].