Figure 3. Treg cells actively expand in tumor associated bone marrow. Blood and bone marrow were immediately stained with anti-CD3, anti-CD4, anti-FOXP3 and anti-Ki67 and were analyzed with LSR II. (A) Representative dot plots showed Ki67 expression in normal vs. tumor bone marrow Foxp3⁺ Treg cells. (B) Results are expressed as the percentage of Ki67 expressing cells in CD4⁺FOXP3⁺CD3⁺ cells (Treg cells) (mean ± SEM) (n = 6–8, *, Tumor bone marrow compared with normal bone marrow, and other compartments, p < 0.001). (C and D) Bone marrow Treg cells expressed different levels of cell cycling genes. Expression of multiple cyclin genes (C) and CDK inhibitors (D) was quantified in bone Treg cells and conventional T cells by real-time PCR. Results are expressed as mean ± SD n = 5, *p < 0.01.