During 5 days of co-culturing, significant HUVEC sprouting toward the tumor spheroids of ASPS cells occurred; however, the sprouting effect was significantly suppressed by Rab27a or Sytl2 knockout and ASPSCR1::TFE3-expression loss (Fig. 6d, e, Supplementary Fig. 6c). This evidence concerns the gene RAB27A and neoplasm.