Cancer-associated fibroblasts in digestive tumors

Figure 1 Hepatocellular carcinoma-associated cancer-associated fibroblasts and hepatocellular carcinoma cells. A: The distribution of H-CAFs identified by α-SMA (+) expression in a HCC specimen is detected by immunohistochemistry. Expression of α-SMA (shown in brown color) is detected to confirm the presence of H-CAFs, which are abundant in tumor tissue; B: The presence of H-CAFs in HCC tissue demonstrated by immunofluorescence. The blue color indicates HCC nucleus, and the green H-CAFs with α-SMA stained. CAFs are circulating the cancer nests in the malignant tissue. HCC: Hepatocellular carcinoma; H-CAF: HCC-associated cancer-associated fibroblasts; α-SMA: α-smooth muscle actin.

Figure 2 The interplay between cancer-associated fibroblasts and tumor cells. Tumor cells activate CAFs by secreting various cytokines and epithelial-mesenchymal transition; CAFs exert their tumor-promoting function through direct (paracrine soluble factors and cell-to-cell contact) and indirect (modulating other stromal components) approaches (Elements adapted from Mueller et al[110]). CAF: Cancer-associated fibroblast; LPA: Lysophostatidic acid; TGF-β: Transforming growth factor-β; NF: Normal fibroblast; α-SMA: α-smooth muscle actin; IL: Interleukin.