1072 THE IMMUNOPHENOTYPE OF LIVER STEM CELLS AND ITS RELATIONSHIP TO HCC DEVELOPMENT ON TOP OF CHRONIC HCV; POSSIBLE PROGNOSTIC SIGNIFICANCE

Background and Aims: Identification of the exact role/significance of different types of liver stem cell markers was investigated. Methods: Sixty core liver biopsies representing chronic HCV, mixed schistosomiasis and chronic HCV, cirrhosis and HCC on top of HCV cirrhosis were stained immunohistochemically with monoclonal antibodies to stem cell markers CK 19, CK 34, OV6 and PCNA. Results: CD 34 was higher in HCC as compared to each of cirrhosis (p = 0.001), hepatitis (p = 0.001) and mixed groups (p = 0.001). Cirrhotics showed higher numbers as compared to HCV (p =0.001) and mixed groups (p = 0.001). No differences were noted between cirrhotics and HCCs. It correlated positively with PCNA/LI in HCV (r = 0.486, p = 0.022), cirrhotics (r = 0.723, p = 0.001) and HCCs (r = 0.871, p = 0.001). No correlations were observed in the combined group. OV 6 positivity was higher in the mixed group as compared to the HCV group (p =0.045). It was totally absent from HCC cases. In the mixed group, it correlated with PCNA/LI (r = 0.982, p = 0.001). It correlated with CK 19 in HCV (r = 0.546, p = 0.009), and cirrhotics (r = 0.868, p = 0.001). CK 19 was higher in the cirrhosis group, it correlated significantly with each of OV 6 in the HCV group and with CD 34 (r = 0.524, p = 0.037).in the cirrhosis group. No CK 19 positivity was detected in HCC group. In the combined group, it correlated with portal infiltrate (r = 0.866, p = 0.026) and spotty necrosis (r = 0.866, p = 0.026). In the cirrhosis group: it correlated with portal infiltrate (r = 0.501, p = 0.048) stage (r = 0.570, p = 0.021) Conclusions: In human HCCs occurring on top of chronic HCV infection, we propose that the immunophenotype of HPCs, whether they express OV6 or CD 34 could be considered as a prognostic sign; OV6 expression is associated with regenerative activity, while CD 34 expression is associated with a high probability of HCC development.