COX-2 expression and tumor angiogenesis in colorectal cancer

AIM:Cyclooxygenase-2 (COX-2) is one of the rate-limitingenzymes in metabolism of arachidonic acid,and COX-2inhibitors demonstrate preventive effects on cancer,especially on colorectal cancer.The underlying mechanismremains unclear.The aim of this study was to illustratethe relationship between angiogenesis and COX-2 incarcinogenesis of colorectal cancer.METHODS:One hundred and seventy patients withcolorectal cancer were enrolled in our study from January1993 to September 2001 in School of Oncology,PekingUniversity.COX-2 and VEGF expression were detected withthe immunohistochemistry (IHC) technique.IHC assayswere carried out with the aid of tissue microarray (TMA)procedure.Specimens from 35 of these patients wereexamined with reverse transcriptase PCR (RT-PCR).RESULTS:COX-2 and VEGF expressions were stronger incolorectal cancer than those in the corresponding normaltissues,at both protein and mRNA levels.One hundredpatients were eligible for analysis after IHC assay of COX-2 and VEGF.The positive rate of VEGF was much higher inCOX-2 positive group (47/85) than in COX-2 negative group(X~2=4.181,P=0.041).The result was further verified bythe result of RT-PCR (X~2=8.517,P=0.003).Correlationcoefficient was 0.409 after Spearman correlation analysis(P=0.015).CONCLUSION:COX-2 may be involved in the course oftumor angiogenesis of colorectal cancer and acts throughVEGF.