PP2A expression and phosphorylation are increased in MNC and CD34⁺ cells from patients destined to progress to BC. The horizontal line represents the mean normal level observed in 10 healthy volunteers. (A) Levels of PP2A protein as assessed by flow cytometry. Mean level in 10 healthy subjects = 21.4 (range, 17.1-25.7). The level of PP2A is high in patients destined to progress to BC, compared with nonresponding patients (P = .001). *Statistically significant difference between No-CCR and normal (P = .002). CCR, n = 14; No-CCR, n = 11; and BC, n = 6. (B) Level of PP2A protein in CD34⁺ cells. The level of PP2A is high in CD34⁺ cells in patients destined to progress to BC. CCR, n = 3; No-CCR, n = 4; and BC, n = 3. (C) Level of phosphorylated (inactive) PP2A protein, as assessed by flow cytometry (mean level in 10 healthy subjects = 1.6; range, 0.8-2.3). Phosphorylated levels of PP2A were greater at diagnosis in CCR (P = .01), No-CCR (P = .002) patients who progressed into BC (P = .012), and at BC (P = .004) compared with normal MNCs. CCR, n = 14; No-CCR, n = 11; and BC, n = 6. (D) Level of phosphorylated (inactive) PP2A protein in CD43⁺ cells. The degree of phosphorylation is greater in the CD34⁺ from patients destined to progress into BC. CCR, n = 3; No-CCR, n = 4; and BC, n = 3.