['To investigate the relationship between the expression of soluble B7-H3 (sB7-H3) in the plasma and hepatitis virus B-associated hepatocellular carcinoma (HBV-HCC).', 'Twenty-three patients with HBV-HCC and 15 healthy donors were enrolled in this study. The level of sB7-H3 in the plasma was detected by ELISA. The expression of sB7-H3 mRNA in peripheral blood monocytes (PBMCs), tumor tissues and peri-tumor normal tissues were determined by relative real-time quantitative PCR (qRT-PCR). The level of membrane B7-H3 (mB7-H3) expressed in tumor tissues and peri-tumor normal tissues were detected by immunohistochemical staining.', 'The level of plasma sB7-H3 in the HBV-HCC patients was significantly higher than that in the healthy donors (P<0.05). However, the level of sB7-H3 mRNA in PBMCs was not significantly different between the HBV-HCC patients and healthy donors (P>0.05). The level of plasma sB7-H3 dropped significantly after the resection of liver tumors (P<0.05). The qRT-PCR showed the expression of sB7-H3 mRNA in tumor tissues and peri-tumor normal tissues were about 60 and 1 800 times higher than those in PBMCs of the corresponding HBV-HCC patients, respectively, and the expression of sB7-H3 mRNA in peri-tumor normal tissues was about 30 times higher than that in tumor tissues. Immunohistochemical staining revealed that the expression of mB7-H3 in peri-tumor normal tissues was higher than that in tumor tissues.'] Does [ Plasma sB7-H3 serve as an assistant diagnostic marker for hepatitis B virus-associated hepatocellular carcinoma ]?