Tumor-supportive fibroblasts have profound effects on the composition of the tumor microenvironment.

<p>(A) Tumor-supportive fibroblasts HFFF2 increase Cal51 tumor cell proliferation and increase stromal components (bottom panel) as compared to tumors formed using Cal51 alone (top panel). Immunohistochemical analysis using antibodies to Ki-67 (proliferation), antigen #7/4 (neutrophils and monocytes), CD31 (blood vessels), and α-SMA (mesenchymal cells). Scale bars represent 50 µm for Ki-67, #7/4 and CD31 and 100 µm for α-SMA. (B) Quantification of Ki-67 positive (proliferating) tumor cells. Five different fields of three different tumors per group were scored. Asterisk indicates a significant difference between cell line only (Cal51shNT) and co-injection (Cal51shNT+HFFF2) groups (p<0.01). Data are expressed as the mean ± SEM. (C–E) Similarly performed quantification of monocytes and neutrophils, endothelial cells, and activated mesenchymal cells (p<0.01).