Since DP1 receptor is not detectable in cardiac tissues (Katsumata et al, 2014), PGD2/DP1 axis mediates glucocorticoid‐induced cardioprotection against ischemia (Tokudome et al, 2009), probably through M2 macrophage‐mediated timely resolution of inflammation in injured hearts (Kong et al, 2016, 2017). The gene discussed is PTGDS; the disease is ischemia.