Expression of DPC4/Smad4 in non-small-cell lung carcinoma and its relationship with angiogenesis

The DPC4 influences tumourigenesis and tumor progression by various mechanisms, including angiogenesis. The aim of this study was to determine whether the expression of DPC4 is related to the angiogenesis in lung cancer and whether it could be involved in its clinical behaviour. Immunohistochemistry revealed that DPC4 was expressed at high level in normal broncho-tracheal epithelium, but at low level in tumor tissues, and closely correlated with tumor lymph node metastasis. This result was further confirmed by Western blot analysis. Furthermore, carcinomas with high DPC4 expression demonstrated low VEGF expression and low MVD (microvessel density) labelled with CD34. In addition, DPC4 siRNA in A549 cells also showed that DPC4 could decrease VEGF protein and mRNA expression, and increase TSP1 protein and mRNA expression. Our findings indicated that DPC4 might be an important biomarker for malignant transformation and be involved in preventing the tumor metastasis by inhibiting tumor angiogenesis.