Abstract:

Objective  To investigate whether malignant gastric stromal tumors contain PAS-positive patterned matrix-associated  vascular channels, that is vasculogenic mimicry(VM) independent of tumor angiogenesis.  Methods 36 tissue samples were divided into three groups: the poorly, the moderately and the highly malignant gastric stromal tumors. Tissue sections were stained with VEGF, CD31 1and periodic acid Schiff (PAS). The number of VEGF, microvascular density (MVD) or vasculogenic mimicry density (VMD) was calculated.  Results PAS-positive patterned matrix-associated vascular channels were detected in 30.56%(11/36) of malignant gastric stromal tumors. The number of VEGF or MVD in tumors containing patterned channels was fewer than that in tumors not containing patterned channels,and there was a significant difference between them(P<0.05). Also, the malignant degree of gastric stromal tumors, and proportion of malignant gastric stromal tumors containing patterned channels and quantity of VMD were increased.  Conclusion  In malignant gastric stromal tumors, there is the VM mechanism underlying some tumor cells deforming themselves and secreting an extracelluar metrix, thus the PAS-positive patterned matrix-associated vascular channels appear and bring a blood supply for tumors to sustain growth and metastasis.

Key words: Vasculogenic mimicry; Tumor angiogenesis; Gastric stromal tumors