High Serum Soluble CD155 Level Predicts Poor Prognosis and Correlates with an Immunosuppressive Tumor Microenvironment in Hepatocellular Carcinoma.

Background Hepatocellular carcinoma (HCC) is one of the most prevalent malignancies with poor prognosis. There is no research about the clinical significance of serum soluble CD155 (sCD155) level for HCC. We aim to explore the prognostic and diagnostic value of sCD155 in HCC patients undergoing curative resection. Methods Serum sCD155 level in HCC patients was determined by enzyme-linked immunosorbent assay. The prognostic significance of sCD155 was evaluated by Cox regression and Kaplan-Meier analyses. CD155 expression and biomarkers of immune cells in HCC tissues were detected by immunohistochemistry staining. The diagnostic significance of sCD155 was evaluated using receiver operating characteristic curve. Results Serum sCD155 level was significantly increased in HCC patients and predicted poor prognosis. The prognostic value of sCD155 remained in low recurrent risk subgroups of HCC. Serum sCD155 level was positively related to CD155 expression in HCC tissues. High serum sCD155 level was associated with decreased numbers of CD8(+)T cells and CD56(+)NK cells and increased number of CD163(+)M2 macrophages. Serum sCD155 level had better performance in distinguishing HCC patients from healthy donors and patients with chronic liver conditions than alpha-fetoprotein. Among patients with alpha-fetoprotein <= 20 ng/ml, serum sCD155 level could differentiate HCC patients from non-HCC patients. Conclusion Serum sCD155 level represents a promising biomarker for diagnosis and prognosis of HCC. High serum sCD155 level may reflect an immunosuppressive tumor microenvironment in HCC.