COX-2 expression and tumor angiogenesis in colorectal cancer.
OBJECTIVE
Cyclooxygenase-2 (COX-2) is one of the rate-limiting enzymes in metabolism of arachidonic acid, and COX-2 inhibitors demonstrate preventive effects on cancer, especially on colorectal cancer. The underlying mechanism remains unclear. The aim of this study was to illustrate the relationship between angiogenesis and COX-2 in carcinogenesis of colorectal cancer.


METHODS
One hundred and seventy patients with colorectal cancer were enrolled in our study from January 1993 to September 2001 in School of Oncology, Peking University. COX-2 and VEGF expression were detected with the immunohistochemistry (IHC) technique. IHC assays were carried out with the aid of tissue microarray (TMA) procedure. Specimens from 35 of these patients were examined with reverse transcriptase PCR (RT-PCR).


RESULTS
COX-2 and VEGF expressions were stronger in colorectal cancer than those in the corresponding normal tissues, at both protein and mRNA levels. One hundred patients were eligible for analysis after IHC assay of COX-2 and VEGF. The positive rate of VEGF was much higher in COX-2 positive group (47/85) than in COX-2 negative group (chi (2) = 4.181, P = 0.041). The result was further verified by the result of RT-PCR (chi (2) = 8.517, P = 0.003). Correlation coefficient was 0.409 after Spearman correlation analysis (P = 0.015).


CONCLUSIONS
COX-2 may be involved in the course of tumor angiogenesis of colorectal cancer and acts through VEGF.
Department of Surgery, Beijing Cancer Hospital, Beijing Institute for Cancer Research, School of Oncology, Peking University, 52 Fucheng Road, Haidian District, Beijing 100036, China.
Ai-Wen
AW
Wu
Jin
J
Gu
Zhen-Fu
ZF
Li
Jia-Fu
JF
Ji
Guang-Wei
GW
Xu
D015179:Colorectal Neoplasms / Q000098:blood supply* / Q000235:genetics*; D051546:Cyclooxygenase 2; D006801:Humans; D007527:Isoenzymes / Q000235:genetics*; D008565:Membrane Proteins; D009389:Neovascularization, Pathologic / Q000235:genetics*; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D012189:Retrospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics*
D007527:Isoenzymes; D008565:Membrane Proteins; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases