Systematic analysis of the effects of Cyp1 deletions (Cyp1b1-/-, Cyp1a1-/-, and both; DKO) and diverse AhR activations (TCDD vs. PAH, 6–24 h) established the overlapping effects of Cyp1b1 deficiency and AhR activation on genes in these assemblies (Figure 1B and Figure 2A). This evidence concerns the gene CYP1B1 and pulmonary arterial hypertension.