A: Cell line-derived xenografts (CDX) were generated using SGC7901 human gastric cancer cells, and included subcutaneous tumors, intraperitoneal metastasis and lung metastasis in mice. B: Patient-derived xenografts (PDX) were generated by implanting tumor tissue derived from an advanced-stage colorectal cancer patient in mice, growing a generation 0 tumor, and by then transplanting G0 tumor tissue to a larger number of mice with G1 tumors. C: Histopathological and immunofluorescence analysis of the PDX models, showing that - apart from collagen content - there were no obvious differences between the original patient tumor and the G0 and G1 PDX tumors. CD31: Blood vessels. Ki67: Proliferating cells. α-SMA: Fibroblasts. CD11b: Macrophages of both mouse and human origin. DAPI: Nuclei. D-I: Histopathological and immunofluorescence analysis of CDX and PDX tumors. CDX tumors presented with higher microvessel density (MVD), more collagen and more macrophages. CD86: M2-like macrophages. CD206: M2-like macrophages. *: P < 0.05, **: P < 0.01, and ***: P < 0.001.