Fig. 3.

The BM is the major site of monocyte production in tumor-bearing mice. (A) Representative flow cytometry plots showing actively proliferating Ly6C^hi monocytes (or promonocytes) in the BM and spleen of Fucci transgenic mice. (B) Actively proliferating (Fucci-green⁺) lineage-negative c-kit⁺ Sca-1⁺ HSCs, lineage-negative c-kit⁺ Sca-1^– CD16/32⁺ CD34⁺ GMP cells, and Ly6C^hi monocytes in the BM, spleen, and whole-body blood of non–tumor-bearing (NT) and tumor-bearing mice (see Fig. S2D for flow cytometry gating). (C) Proportions of actively proliferating Ly6C^hi monocytes in the BM, spleen, and blood. (D) Expression levels (mean fluorescence intensity) of Fucci-orange in Fucci-green⁻ monocytes from the BM, spleen, and blood of day-33 tumor-bearing mice. Fucci-orange accumulates during the G1 phase of the cell cycle, thus providing an indication of the time elapsed since last cell division. **P ≤ 0.01; ***P ≤ 0.001 (comparisons as indicated). ^††P ≤ 0.01; ^†††P ≤ 0.001 (compared with non–tumor-bearing control). Data represent means ± SEM (n = 6–8) and are representative of two independent experiments.