Even though WISP-1 knockdown had no significant effect on vessel density in GSC-derived xenografts in this study, more could be investigated in terms of its relationship with proangiogenic factors such as VEGF, which is positively regulated by WISP-1 to remodel vasculature in human osteosarcoma and oral squamous cell carcinoma. This evidence concerns the gene CCN4 and oral cavity squamous cell carcinoma.