Tumour vasculogenic mimicry is associated with poor prognosis of human cancer patients: a systemic review and meta-analysis.

BACKGROUND: Vasculogenic mimicry (VM) has been reported in various malignant tumours and is known to play an important role in cancer progression and metastasis. However, the impact of VM on the overall survival of human cancer patients remains controversial. The goal of this study was to evaluate whether VM is associated with 5-year survival of human cancer patients.
METHODS: Twenty-two eligible clinical studies with data on both tumour cell-dominant VM and the 5-year survival of 3062 patients involved in 15 types of cancers were pooled in the meta-analysis.
RESULTS: The 5-year overall survival of VM-positive and -negative cancer patients was 31% and 56%, respectively. The relative risk (RR) of the 5-year survival of VM-positive patients was significantly higher than that of VM-negative cases (RR=1.531; 95% confidence interval (CI): 1.357-1.726; P<0.001). Notably, metastatic melanoma patients demonstrated a higher VM rate (45.3%) than patients with primary melanoma (23.1%) and showed worse 5-year survival, suggesting that VM contributes to tumour metastasis and poor prognosis in cancer patients. Subgroup analysis indicated that a poor 5-year survival was significantly associated with eight types of VM-positive malignant tumours, such as lung, colon, liver cancers, sarcomas and melanoma; but was not associated with the seven other types of cancers, such as prostate cancer. Heterogeneity and publication biases were found among the 22 studies, mainly due to the divergent characteristics of cancers and extremely low survival rate in six types of malignant tumours.
CONCLUSION: VM-positive cancer patients show a poor 5-year overall survival compared with VM-negative malignant tumour cases, particularly in metastatic cancer.