T regulatory cells (T regs) are a recently identified subset of T cells with inhibitory functions on the immune system. In cancer, it has been shown that there is an increased proportion of T regs in several different human malignancy states. T regs are found to be elevated in peripheral blood mononuclear cells, draining lymph nodes and in the primary tumor itself. There has also been correlation between peripheral blood T regs and tumor stage, tumor relapse and survival. It has been proposed that the T regs are activated and expanded by factors produced by the tumor microenvironment. They are thought to play a role in preventing or demising host T-cell responses against cancer, including a suboptimal host responses to vaccine strategies. Strategies to reduce T regs in cancer patients are being explored as a novel immunologic anti-cancer approach.

Renal cell cancer (RCC) is a tumor with well-known immune-mediated phenomena such as spontaneous regression. There is paucity of data on T regs in RCC.

We propose to study the frequency of peripheral blood T regs before and after nephrectomy for RCC. We will document the baseline frequency of T regs in RCC and if nephrectomy results in a change in levels. We hypothesize that nephrectomy will lower peripheral T regs to normal levels in early stage RCC, and will reduce peripheral T reg levels in advanced RCC patients. If found to be so, T regs could in future be used as an indicator of disease recurrence in early stage RCC. In advanced RCC, lowering of T reg levels may help explain the previous hypothesis that debulking nephrectomy results in improved anti-tumor immunity, provide rationale for second debulking procedures, and be correlated with subsequent clinical course.

The main laboratory technique is flow cytometry. This will be a pilot study with small patient numbers. Only blood samples are required.