M2 macrophage recruitment increased in relapse-prone tumors after a single dose of CTX treatment. (A) Schedule of CTX treatment. (B) Tumor growth curves of 4T1 tumor-bearing mice treated with PBS (control, n = 7) and different doses of CTX; CTX-S (single dose, 150 mg/kg, n = 12), CTX-M (multiple doses, 75 mg/kg, every 3 days, six times, n = 12); (C-F) Representative dot plots (C), quantified CD206-F4/80+ and CD206+F4/80+ cell percentages (D, E), and CD206+F4/80+-to-CD206-F4/80+ ratios (F) from flow cytometry analysis of CD206 and F4/80 in 4T1 tumors treated with different doses of CTX (n = 5 per group). (G) Immunofluorescence staining of CD206 and F4/80 in 4T1 tumor tissues after PBS and CTX treatments. Scale, 75 µm. *, P <0.05; **, P <0.01; ***, P <0.001.