All of the tumor growth-promoting factors identified in glioblastoma cyst fluid are known to be present in blood, including hormones, kininogen-1, osteopontin, GRP78, SPARCL1, HRG, LRG, α-2-HS-glycoprotein, MIF, VEGFA, kallikrein, IGFBP2, CD166, clusterin, CD5L, and hepatocyte growth factor activator [49]. This evidence concerns the gene KLK4 and neoplasm.