Background: Production of the glycoprotein hormone hCG beta has been associated with aggressive behavior in nontrophoblastic tumors. In this study the prognostic value of serum level and tissue expression of hCG beta were compared in 232 patients with colorectal cancer.
Materials and methods: Serum levels were measured with a hCG beta specific immunofluorometric assay. Tissue specimens were stained with the same monoclonal antibody as in the serum assay.
Results: The proportion of patients with a positive immunohistochemical expression of hCG beta was higher (22%) than the proportion with elevated serum levels (17%). The correlation between serum and tissue expression was moderate (kappa 0.298). Both serum and tissue expression of hCG beta were independent prognostic factors. hCG beta serum level was a stronger prognostic factor than tissue expression both in uni- and in multivariate analysis. The accuracy when predicting 5-year survival status of the patients was highest (63%) when using the combined results of serum and tissue expression.
Conclusions: There is a moderate correlation between hCG beta expression in serum and in tissue. The predictive accuracy of serum hCG beta was higher than the predictive accuracy of tissue expression, and the prognostic accuracy was further slightly increased when using a combination of tissue and serum expression.