CD34 and coronary artery disorder: The combined expression values of all 4 genes also showed a high correlation coefficient (R = 0.91, p < 0.0001) with the average expression of the 303 genes expressed at higher levels in CAD patients (R = 0.91, p < 0.0001, data not shown), which is suggestive for a causal role of RARα stimulation by its ligand, all-trans retinoic acid, in the upregulation of genes in CD34+ cells in CAD patients.