EPO and colonic neoplasm: Naturally, the overexpression of HIF-1α upregulated VEGF and EPO protein and mRNA levels in the cells (Figure 2E and 2F, lane 5), silencing of HIF-1α abolished the upregulation of VEGF and EPO protein and mRNA levels mediated by ZFP91 (Figure 2E and 2F, lane 4), supporting that ZFP91 is able to upregulate HIF-1α in colon cancer cells.