VTCN1 and osteosarcoma: Significantly higher serum expression of B7-H4 in gastric cancer (242, 243), NSCLC (244, 245), HCC (246, 247), RCC (248–250), bladder urothelial carcinoma (251), ovarian cancer (252, 253), and osteosarcoma (254) has been reported in comparison to normal healthy individuals or control groups.