COPD genes: SH3PXD2B, CORIN, SELL, TRAF3IP3, BHLHE22; LUAD genes: IGFBP2, CDKN2A, MUC5B, CEACAM5, ELF3, MAD2L1, BUB1B, CENPF, TOP2A, ASPM; COPD-LUAD essential genes: GPI, EZH2, EFNA4, CFB, ENO1. Here, EFNA4 is linked to chronic obstructive pulmonary disease.