In the 29 ex vivo lung samples used for miRNA microarray profiling, qRT-PCR confirmed that expression of both SERPINE1 (fold-change >2.2) and HNF4A (fold-change >1.3) had generally higher expression in association with lower miR-34c expression; however only SERPINE1 (p = 0.05) was significantly differentially expressed between mild and moderate emphysema (Figure 3) in this cohort, and it was correspondingly upregulated in more severe disease in both TPCH-KCO (fold change >1.2, p < 0.05) and Spira (fold change >1.13) datasets (Figure 2). Here, HNF4A is linked to pulmonary emphysema.