Study of cyclooxygenase-2 in renal cell carcinoma.

Cyclooxygenase (COX)-2 plays an important role in the development of various cancers due to its angiogenetic function. As the expression of COX-2 is up-regulated in human colorectal carcinoma and other cancers, we investigated the expression of COX-2 in human renal cell carcinoma (RCC) tissues. One hundred and eight specimens were obtained from patients with RCC, and 20 from normal kidney (NK) tissues. Immunohistochemistry, using affinity purified anti-bodies against human COX-2, and RT-PCR to study the COX-2 mRNA expression were carried out. We also examined whether or not there was a significant difference in the expression of COX-2 among grades (G1, G2, G3) and stages (pT1, pT2, pT3a, pT3b) in RCC. While no marked expression of COX-2 was observed in the NK tissues, a significantly strong expression of COX-2 was detected in RCC tissues. The extent and intensity of immunoreactive COX-2 polypeptides in cancer cells were statistically greater than those of cells from normal kidney tissues. However, no marked difference was seen among grades or between stages. These results demonstrate that the generated COX-2 in human renal cell carcinoma plays an important role in the proliferation of malignant renal cells.