In Figure 2(a), serum Cav1 level was significantly low in IPAH compared to non-PAH and COPD-PH group (76.45 ± 32.41 versus 140.75 ± 59.72 pg/mL and 173.57 ± 42.75 pg/mL; p = 0.014 and p = 0.047). The gene discussed is CAV1; the disease is chronic obstructive pulmonary disease.