At the very least, understanding the details of the PHD:HIF‐α interaction may be useful in optimising PHD inhibitors, for example, some inhibitors more efficiently displace HIF‐α from the PHDs than others.37 The development of substrate‐selective inhibitors is of particular interest given the distinct physiological roles of HIF‐1 and HIF‐2 target genes.5a, 72 Further, compounds that promote PHD activity are also of interest, in particular from a cancer pharmaceutical perspective. This evidence concerns the gene PDC and cancer.