CD31 as well as ERG staining of the lung from LR/HIF-1αΔ/Δ mice showed decreased microvessel density and reduced angiogenesis (Figure 3A, and Supplementary Figure 2A) along with reduced tumor cell proliferation (Figure 3B, and Supplementary Figure 2B) with no changes in tumor cell apoptosis (data not shown) compared to CC-LR mice in the presence or absence of NTHi-induced COPD-like airway inflammation. Here, PECAM1 is linked to chronic obstructive pulmonary disease.