Expression of cancer-associated fibroblast markers in advanced colorectal cancer

Colorectal cancer is one of the most common causes of mortality from cancer worldwide. Previous studies have demonstrated that cancer-associated fibroblasts (CAFs) promote neoangiogenesis and tumor growth for various tumors. The present study analyzed CAF markers, including alpha-smooth muscle actin (alpha-SMA), collagen I, platelet-derived growth factor receptor-beta (PDGFR-beta), and D2-40 (antibody recognizing podoplanin), and vessel markers, including cluster of differentiation (CD) 31 and CD34, for 121 advanced colorectal cancer cases using a digital image analyzing technique. The association between CAF markers and vessel markers with clinicopathological factors was investigated. Furthermore, the association between CAF markers with each other, and their association with vessel markers was analyzed. Mean/median expression area of stromal and vessel markers in tumors were collagen I, 26.787%; D2-40, 1.372%; PDGFR-beta, 11.646%; alpha-SMA-positive and desmin-negative myofibroblasts (alpha-SMA subtraction), 15.372%; CD31, 3.635%; and CD34, 2.226%. The expression area of alpha-SMA subtraction was significantly correlated with collagen I (P<0.001, correlation rho=0.509). High levels of alpha-SMA subtraction (P=0.002), collagen I (P=0.040), and PDGFR-beta (P=0.040) expressions tended to be associated with high venous invasion. D2-40 did not correlate with other CAF and vessel markers. These results indicated that individual CAFs may have different expression patterns, and different strength effects for venous invasion in advanced colorectal cancer stroma.