Vasculogenic mimicry is associated with high tumor grade, invasion and metastasis, and short survival in patients with hepatocellular carcinoma

Vasculogenic mimicry (VM) has increasingly been recognized as a form of angiogenesis. In VM, epithelial cells are integrated into the malignant tumor vasculature. An association has been observed between VM and poor clinical prognosis in some malignant tumors. However, whether VM is present and clinically significant in hepatocellular carcinoma (HCC) is unknown. In this study, we determined whether VM was present in HCC and whether it was associated with tumor grade, invasion and metastasis, and survival duration. We collected paraffin-embedded HCC tumor samples, along with complete clinical and pathologic data for all the cases, and performed immunohistochemical staining for CD31, CD105 (endoglin), hepatocyte, vascular endothelial growth factor, matrix metalloproteinase (MMP)-2, and MMP-9. The VM status was compared with the clinical and pathological data using statistical tests. Kaplan-Meier survival analysis and log-rank test were used to compare survival durations between patients with and without VM. The VM vessel cells were CD31 and CD105-negative and hepatocyte and vascular endothelial growth factor-positive, showing that they were not derived from endothelial cells but were HCC tumor cells. Patients with VM had a higher metastasis rate than did those without VM (P=0.003). Consistent with this finding, MMP-2 and MMP-9 were present in all the VM cases but were found less frequently in non-VM cases (P<0.05). The Kaplan-Meier survival analysis showed that patients in the VM group had a significantly shorter survival duration than did those in the non-VM group. In conclusion, VM is a marker of poor clinical prognosis in HCC: Its presence may be associated with a high tumor grade, invasion and metastasis, and short survival.