Prognostic significance of receptor-binding cancer antigen expressed on SiSo cells (RCAS1) expression in relation to cadherin expression in patients with colorectal carcinoma.

PURPOSE: This study was designed to assess the prognostic value of receptor-binding cancer antigen expressed on SiSo cells expression and its relationship with cadherin expression in patients with colorectal cancer. METHODS: The expressions of receptor-binding cancer antigen expressed on SiSo cells and E-cadherin were analyzed with special reference to prognosis in 105 patients with colorectal cancer. RESULTS: Receptor-binding cancer antigen expressed on SiSo cells immunoreactivity was detected in the membrane and cytoplasm of tumor cells and considered to be positive in 48 patients (45.7 percent). The expression of receptor-binding cancer antigen expressed on SiSo cells was significantly correlated with lymph node metastasis (P = 0.0004), venous invasion (P = 0.0062), Dukes stages (P < 0.0001), and serum levels of carcinoembryonic antigen (P = 0.014). Furthermore, receptor-binding cancer antigen expressed on SiSo cells expression was significantly correlated with a poor prognosis (P < 0.001), and multivariate analysis indicated that it was an independent prognostic indicator. The expression of receptor-binding cancer antigen expressed on SiSo cells was more frequently found in tumors with reduced or abnormal expression of E-cadherin. The survival time of patients with reduced/abnormal E-cadherin expression was significantly shorter than that of patients with normal E-cadherin expression among patients with receptor-binding cancer antigen expressed on SiSo cells expression (P = 0.0043) but did not differ for those without receptor-binding cancer antigen expressed on SiSo cells expression (P = 0.17). Furthermore, multivariate analysis revealed that reduced/abnormal expression of E-cadherin was an independent prognostic factor in patients with receptor-binding cancer antigen expressed on SiSo cells expression but not in those without receptor-binding cancer antigen expressed on SiSo cells expression. CONCLUSIONS: Receptor-binding cancer antigen expressed on SiSo cells expression is significantly correlated with tumor progression and poor prognosis in patients with colorectal cancer. Both reduced E-cadherin and enhanced receptor-binding cancer antigen expressed on SiSo cells expression may be critical for the mechanism of metastasis and recurrence in human colorectal cancer.

Tumor cyclooxygenase-2 gene suppresses local immune responses in patients with hepatocellular carcinoma.

AIMS AND BACKGROUND: In several neoplastic diseases including hepatocellular carcinoma (HCC) immunosuppression is correlated with disease stage, progression and outcome. Moreover, recent studies have demonstrated that cyclooxygenase-2 (COX-2) enhances tumor growth in HCCs. The present study analyzed the correlation between local immune responses and COX-2 gene expression levels in patients with primary HCCs. METHODS: Fresh tissues were obtained from 59 patients who underwent resection of an HCC. The COX-2 gene expression levels were quantified by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and compared with the CD8+ T cell densities detected by immunohistochemistry. RESULTS: COX-2 gene expression was detected in 35 of the 59 tumors. The CD8+ T cell density in COX-2-expressing tumors (6.1 cells/high-power field (HPF), x200 magnification) was suppressed compared with that in non-COX-2-expressing tumors (13.6 cells/HPF, P = 0.009). Tumor COX-2 gene expression was associated with a poorer disease-free survival rate. CONCLUSIONS: Elevation of the tumor COX-2 level is correlated with the suppression of local immune responses in HCCs, suggesting that COX-2 plays a role in early tumor recurrence in the residual liver in patients after HCC resection.