AIM:To investigate whether microsomal prostaglandin E synthase-1 (mPGES-1) expression in hepatocellular carcinoma (HCC) and in non-cancerous liver affects HCC prognosis after hepatectomy. METHODS: The relationship between patient clinical prof iles, tumor factors, surgical determinants, and mPGES-1 expression and the recurrence-free survival rate were examined in 64 patients who underwent curative hepatectomy between March 2003 and December 2006. RESULTS: The scores for mPGES-1 expression were higher in well differentiated and moderately differentiated HCC tissues than in poorly differentiated HCC tissues (well differentiated, 5.1 ± 2.7; moderately differentiated, 5.1 ± 1.7; poorly differentiated, 3.0 ± 1.8). In noncancerous liver tissues, the mPGES-1 levels were higher in injured liver tissues than in normal tissues. Cirrhotic livers had higher mPGES-1 levels than livers with chronic hepatitis (normal livers, 3.3 ± 0.7; chronic hepatitic livers, 5.4 ± 1.9; cirrhotic livers, 6.4 ± 1.6). A univariate analysis revealed that the recurrence-free survival rate was signif icantly lower in patients with vascular invasion,a higher mPGES-1 level in non-cancerous liver tissue,a larger tumor diameter (≥5 cm), and a lower serum albumin level (≤3.7 g/dL). The mPGES-1 expression in HCC tissues did not correlate well with postoperative recurrence. A multivariate analysis demonstrated that the presence of vascular invasion and higher mPGES-1 levels were statistically significant independent predictors for early postoperative recurrence of HCC.CONCLUSION: Increased mPGES-1 expression in noncancerous liver tissues is closely associated with the early recurrence of HCC after curative resection. AIM: To investigate whether microsomal prostaglandin E synthase-1 (mPGES-1) expression in hepatocellular carcinoma (HCC) and in non-cancerous liver affects HCC prognosis after hepatectomy. METHODS: The relationship between patient clinical prof iles, tumor factors, surgical determinants , and mPGES-1 expression and the recurrence-free survival rate were examined in 64 patients who underwent curative hepatectomy between March 2003 and December 2006. RESULTS: The scores for mPGES-1 expression were higher in well differentiated and moderately differentiated HCC tissues than in poorly differentiated HCC tissues (well differentiated, 5.1 ± 2.7; moderately differentiated, 5.1 ± 1.7; poorly differentiated, 3.0 ± 1.8). In noncancerous liver tissues, the mPGES-1 levels were higher in injured liver tissues than in normal tissues. Cirrhotic livers had higher mPGES-1 levels than livers with chronic hepatitis (normal livers, 3.3 ± 0.7; chronic hepatitic livers, 5.4 ± 1.9; cirrhotic livers, 6.4 1.6). A univariate analysis revealed that the recurrence-free survival rate was signif icantly lower in patients with vascular invasion, a higher mPGES-1 level in non-cancerous liver tissue, a larger tumor diameter (> 5 cm), and a lower The mPGES-1 expression in HCC tissues did not correlate well with postoperative recurrence. A multivariate analysis demonstrated that the presence of vascular invasion and higher mPGES-1 levels were significantly different independent predictors for early postoperative recurrence of HCC.CONCLUSION: Increased mPGES-1 expression in noncancerous liver tissues is closely associated with the early recurrence of HCC after curative resection.