Plasma proteosome level as a potential marker for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a fatal malignancy. Effective curative surgery is achieved when HCC is detected earlier. Proteosomes, the main non-lysosomal proteolytic structures organising the cellular mechanisms of cleaving proteins, can be considered a tumour marker in many kinds of malignancies. The aim of this study was to assess the plasma proteosome level in HCC and cirrhosis and, accordingly, evaluate its potential diagnostic ability in the detection of HCC in cirrhosis.

This study included 60 patients, divided into two groups: the HCC group and the liver cirrhosis group. Twenty normal subjects served as a control group. Serum levels of proteosome and alpha-foetoprotein (AFP) were measured using the enzyme-linked immunosorbent assay (ELISA) technique.

Plasma proteosome levels were significantly higher in patients with HCC and in patients with cirrhosis without HCC when compared to controls individually (p>0.002 and p>0.001, respectively) but did not reach a significant differentiating level between them (area under curve (AUC)=0.641, p=0.061). Moreover, the plasma proteosome level was not correlated with the severity of HCC by the Milan criteria or with AFP level. In addition, it was not significantly related to laboratory or Child-Pugh scoring. Moreover, the combined use of plasma proteosome level and AFP measurements for the diagnosis of HCC was not effective.

In this study, the plasma proteosome level was comparably recorded in both patients with cirrhosis and patients with HCC (mean value±standard deviation were 5.796±1.46 and 7.176±2.48μgml(-1), respectively), not reaching a significant differentiating level between them, although predictability of HCC using the plasma proteosome level was significant (p=0.017).