As shown in Fig. 6a, enhanced T and NK cell proliferation – as evidenced by increased expression of the proliferation marker Ki67 – was clearly found in blood, spleen, and lymph nodes but not in irradiated tumor and bone marrow, again suggesting that i.p. injected IL-2c preferentially expand CD122+ cells in blood and secondary lymphoid organs. This evidence concerns the gene MKI67 and neoplasm.