Abstract
There is cumulative evidence that stromal reaction in cancer has an important diagnostic and prognostic significance. The aims of this study were to analyze the expression of basic fibroblast growth factor (FGF-2), CD31, and alpha-smooth muscle actin (SMA) in esophageal cancer patients and to establish their significance as indicators of disease recurrence after definitive chemoradiation (CRT). Protein expressions of FGF-2, CD31, and SMA were evaluated by immunohistochemistry and Western blot analysis in 70 patients, 20 with esophageal squamous cell carcinoma (ESCC) and 50 with locally recurrent ESCC after definitive CRT. Twenty matched normal esophageal squamous epithelium were also studied as controls. Esophageal cancer tissues showed positive expression of FGF-2, CD31, and SMA; in contrast, FGF-2 expression was not detected and only little staining for CD31 and SMA was noted in normal epithelium. Protein levels of FGF-2, CD31, and SMA were significantly elevated in recurrent ESCC. Among the patients with locally recurrent disease, expression of FGF-2 and SMA was notably high in whom the tumor recurred locally within 24 months after definitive CRT. The 2- and 5-year local recurrence-free survival rate was 15.4 % and 0 in patients with high FGF-2 expression, compared with 45.8 and 33.3 % in those who expressed low FGF-2, respectively (P = 0.005). Of patients who expressed high SMA, the 2- and 5-year local recurrence-free survival rate was 21.7 and 8.7 %, respectively, compared to those with low SMA expression which was 37.0 and 22.2 %, respectively (P = 0.016). Overexpression of FGF-2 and SMA is associated with local recurrence and reduced recurrence-free survival after definitive CRT for ESCC. The data also suggest that targeting stromal cells may be an attractive approach for esophageal cancer therapy strategies.