Diagnostic and prognostic role of SCCA-IgM serum levels in hepatocellular carcinoma (HCC)

Background and aim: The serpin squamous cell carcinoma antigen complexed with IgM (SCCA-IgM) has been reported as a promising serological marker for hepatocellular carcinoma (HCC). We aimed to further evaluate SCCA-IgM diagnostic accuracy and to determine its prognostic role.

Methods: SCCA-IgM levels were determined in 327 sera obtained from 81 HCC patients, 206 cirrhotics and 40 healthy blood donors (controls). Sensitivity, specificity, correlation with clinical and tumor parameters and with survival were evaluated.

Results: HCC patients had SCCA-IgM levels significantly higher than controls and cirrhotics (P < 0.0001). Sensitivity, specificity, positive and negative predictive values for HCC were 89%, 50%, 41% and 92%, respectively. In comparison, sensitivity and specificity for alphafetoprotein were 48% and 85%. SCCA-IgM levels were not significantly correlated with clinical or biological variables. With a cut-off of 130 AU/mL (receiver operating characteristic curves), SCCA-IgM proved efficient in the prediction of prognosis, identifying the patients with long overall survival (efficiency validated in the homogenous subgroup of patients with intermediate-stage HCC undergoing transarterial chemoembolization) and predicting progression-free survival. A Cox multivariate analysis confirmed SCCA-IgM predictive value, identifying tumor size and SCCA-IgM levels as independent predictors of survival. A reduction in SCCA-IgM levels correlated with response to treatment.

Conclusions: SCCA-IgM is a sensitive marker of HCC in patients with cirrhosis even though lacking in specificity. The determination of the levels of the marker in HCC patients is highly efficient in predicting the patients' prognosis, identifying those with long overall and progression-free survival and the responders and should be introduced in the clinical practice.