Study on vasculogenic mimicry in malignant esophageal stromal tumors

AIM: To investigate whether malignant esophageal stromaltumors contain PAS-positive patterned matrix-associatedvascular channels, which are lined by tumor cells, but notvascular endothelial cells. That is vasculogenic mimicry(VN) independent of tumor angiogenesis.METHODS: Thirty-six tissue samples of/nalignantesophageal stromal tumors were analyzed. Tissuesections were stained for Vascular endothelial growthfactor (VEGF), CD31 and periodic acid Schiff (PAS). Thelevel of VEGF, the microvascular density (MVD) and thevasculogenic mimicry density (VID) were determined.RESULTS: PAS-positive patterned matrix-associatedvascular channels were detected in 33.3% (12/36)of tumor samples. Within these patterned channels,red blood cells were found. The level of VEGF and theMVD in tumors containing patterned channels weresignificantly higher than those in tumors not containingpatterned channels (P < 0.05). At the same time, themalignant degree of tumors was higher, the proportionsof tumors containing patterned channels were not onlymore, but also in the each kind of tumors containingpatterned channels.CONCLUSION: In malignant esophageal stromaltumors, a VM mechanism causes some tumor cells todeform themselves and secrete extracellular matrix;thus, PAS-positive patterned matrix-associated vascularchannels appear and supplying blood to the tumors tosustain their growth and metastasis.