The Simultaneous Expression of Peroxisome Proliferator-Activated Receptor Delta and Cyclooxygenase-2 May Enhance Angiogenesis and Tumor Venous Invasion in Tissues of Colorectal Cancers

We conducted this study to evaluate the impact of the expression of peroxisome proliferator-activated receptor delta on angiogenesis in tissue samples of colorectal cancer. We examined 52 samples of primary human colorectal carcinomas and matched normal adjacent tissues to evaluate the expression of peroxisome proliferator-activated receptor delta, cyclooxygenase-2, vascular endothelial growth factor-A, and CD34 through immunohistochemical analysis. Peroxisome proliferator-activated receptor delta was expressed in 25 (48.1%), and cyclooxygenase-2 was expressed in 26 (50.0%) of total colorectal cancer tissues. Tissue samples were divided into four groups, according to the expression of peroxisome proliferator-activated receptor delta and cyclooxygenase-2. The positive rate of vascular endothelial growth factor-A, the levels of microvascular density, and the incidence of venous vessel invasion in peroxisome proliferator-activated receptor delta (+)/cyclooxygenase-2 (+) samples exceeded significantly those in the other three groups of tissue samples (P < 0.05). The results suggest that the axis of the cyclooxygenase-2/peroxisome proliferator-activated receptor delta signal pathway might play a crucial role in the development of colorectal cancers by enhancing angiogenesis.