Expression of apolipoprotein M in human hepatocellular carcinoma tissues

The present study examined mRNA levels and protein mass of apolipoprotein M (apoM) in human hepatocellular carcinoma (HCC) tissues and in the adjacent tissues. Plasma apoM levels in these HCC patients were also determined and compared to the normal subjects. The mean level of plasma apoM in the HCC patients was 0.61±0.30 OD mm−2, which was significantly higher than that in the normal subjects 0.37±0.07 OD mm−2 (P<0.01). However, both apoM mRNA levels and apoM protein mass in the HCC tissues were significantly lower than in the adjacent tissues (P<0.05). It is concluded that human hepatocellular carcinoma tissues had a reduced capacity to produce apoM than the adjacent non-tumor tissues. However, the plasma apoM levels were higher in the HCC patients than in normal subjects, which suggested that tissues adjacent to the tumors or extra-hepatic apoM production in the HCC patients may contribute to the higher plasma apoM levels in these patients. The clinical significance of apoM in relation to HCC still needs further investigation.