Many of these genes correlated positively with the HIF metagene in multiple tumor-specific datasets, including the canonical HIF target genes ALKBH5, BNIP3, EGLN3, GAPDH, P4HA2, PDK1, PFKL, PFKP, PLOD1, and TPI1. This co-variation of the HIF metagene with other HIF target genes confirms an underlying biological variation in HIF metagene expression within each tumor type. The gene discussed is PDK1; the disease is neoplasm.