In nude mice, the growth, weight, Ki-67 proliferation index, and CD31-positive microvessels of subcutaneous xenograft tumors formed by NB cells were increased and decreased by stable over-expression or knockdown of HNF4A-AS1, respectively (Fig. 2h and Additional file 1: Figure S7c, d). The gene discussed is PECAM1; the disease is neuroblastoma.