FIGURE 2.

Tumor‐associated macrophages (TAMs) secreted transforming growth factor‐β (TGF‐β) to facilitate colorectal cancer development. A, TGF‐β concentration was detected in the culture medium of TAMs and blood‐derived macrophages (BDMs) (105 macrophages in 1 mL culture medium for 48 h). B, Immunohistochemical staining of TGF‐β in tumor tissues from metastasis (M) and nonmetastasis (N) colorectal cancer patients. Expression intensity was calculated by Image‐Pro Plus 6.0 (n = 15 per group). Scale bar, 100 μm. C, Colony formation rates of CT26/HCT116 cells treated with PBS or TGF‐β (100 ng/mL). D, Tumorigenesis capability of CT26/HCT116 cells in NOD‐SCID mice was examined after PBS or TGF‐β (100 ng/mL) treatment. E, Numbers of relative migrating CT26/HCT116 cells treated with PBS or TGF‐β (100 ng/mL). **P < .01