Summary Epidemiological studies have demonstrated that nonsteroidal anti-inflammatory drugs (NSAIDs), known to inhibit cyclooxygenase (COX), reduce the risk of colorectal cancer. COX is a key enzyme in prostaglandin biosynthesis, and two isoforms of COX, COX-1 and COX-2, have been identified. Recently COX-2 has been reported to frequently overexpress in colorectal neoplasms and to play a role in colorectal tumorigenesis and tumour progression. In this study, using immunohistochemistry, we examined COX-2 expression in advanced human colorectal cancer and its correlation with clinicopathological features. COX-2 expression was observed mainly in the cytoplasm of cancer cells in all the specimens examined, but some stromal cells and endothelial cells were also stained. According to the grade of COX-2 expression of the cancer cells, patients were divided into high-and low-COX-2 expression groups. High-COX-2 expression significantly correlated with tumour recurrence, especially haematogenous metastasis. These results suggest that a selective COX-2 inhibitor can be a novel class of therapeutic agents not only for tumorigenesis but also for haematogenous metastasis of cololectal cancer. To our knowledge, this is the first report on the correlation between COX-2 overexpression and recurrence of colorectal cancer.

in colorectal tumours and play a role in colorectal tumorigenesis. Recently it has been reported that selective inhibition of COX-2 inhibits colon cancer cell growth. In this study we investigated the effect of a selective COX-2 inhibitor (JTE-522) on haematogenous metastasis of colon cancer. For this purpose, we selected a murine colon cancer cell line, colon-26, that constitutively expresses the COX-2 protein. The subclone P expressed a high level of COX-2 and the subclone 5 expressed a low level. The colon-26 subclones were injected into the tail vein of BALB/c mice. JTE-522 was given intraperitoneally every day from the day prior to cancer cell injection, and the mice were sacrificed 16 days after cell injection. Lung metastases were compared between groups with and without JTE-522. In the mice injected with subclone P, the number of lung metastatic nodules was significantly reduced in the treated group. However, in the mice injected with subclone 5, there was little difference between the control and the treated groups. These results indicate that there may be a direct link between inhibition of haematogenous metastasis of colon cancer and selective inhibition of COX-2, and that selective COX-2 inhibitors may be a novel class of therapeutic agents not only for colorectal tumorigenesis but also for haematogenous metastasis of colon cancer. © 1999 Cancer Research Campaign Keywords: COX-2; colon cancer; metastasis; apoptosis; MMP; selective COX-2 inhibitor 1274British Journal of Cancer (1999) 81(8), 1274-1279 © 1999 Cancer Research Campaign Article no. bjoc.1999 Received 3 November 1998 Revised 18 March 1999 Accepted 19 April 1999 Correspondence to: S Tomozawa Inhibition of colon cancer metastasis by a selective COX-2 inhibitor 1275

Background. Degradation of basement membrane and extracellular matrix by matrix metalloproteinases (MMPs) is believed to be an essential step in the complicated process of hematogenous metastasis. MMP-1 is a member of collagenases, a family of MMPs that degrades collagens type I, II, and III, main components of the interstitial stroma.The purpose of this study was to investigate the expression of MMP-1 in colorectal cancer and its correlation with hematogenous metastasis.Patients and Methods. We examined 133 cases of colorectal cancer (Dukes A: 72; Dukes B: 26; Dukes C: 23; Dukes D: 12). Sections were cut from formalin-fixed, paraffin-embedded samples containing the deepest site of cancer invasion and stained immunohistochemically with a monoclonal antibody to MMP-1. According to the area

Background: Current gene expression analysis relies on the assumption that the isolated RNA represents all species of mRNA in proportions equal to those in the original materials. No system is available for absolute quantification of mRNA. Methods: We applied whole blood to 96-well filterplates to trap leukocytes. Lysis buffer containing cocktails of specific reverse primers and known concentrations of synthetic external control RNA (RNA34) was added to filterplates, and cell lysates were transferred to oligo(dT)-immobilized microplates for hybridization. We then synthesized the cDNA in the oligo(dT)-immobilized microplates from these primer sites and used the cDNA for real-time PCR. RNA34 acted as a universal control, and gene amplification results were converted to quantities of mRNA per microliter of whole blood after the recovery of RNA34 in each sample was determined. Results: Under fully optimized conditions, both added RNA34 and native mRNA species exhibited ϳ10% recovery from whole blood to real-time PCR. When whole blood was stimulated ex vivo, changes in gene expression as low as 30%-40% were detected with statistical significance, and the experimental CVs were low (10%-20%). Conclusion: This new system to estimate mRNA copies per microliter of whole blood may allow standardization of gene-expression-based molecular diagnostics.