Expression of TGF-β, FAP and Twist in cancer tissues and para-carcinoma tissues. Key factors in the cell signaling pathway including TGF-β (a-f) and Twist (g-l) were detected by immunohistochemistry. The expression of TGF-β and Twist in I (inflammation pseudotumor) is not included in the figure. In these samples, TGF-β was located in cytoplasm (a, c, e) and Twist (g, I, k) can be detected both in cytoplasm and nuclei of cancer cells. FAP, a marker of CAFs, was expressed in the cytoplasm of cancer cells rather than in the stroma of cancer tissues (m, o, q). This novel result may indicate that some cancer cell could secret FAP just like CAFs or these cancer cells secreting FAP may be a novel origin of CAFs. However, TGF-β (b, d, f), Twist (h, j, l) or FAP (n, p, r) were negatively expressed by all of the para-carcinoma tissues. Magnification: 40×.