OR4K2 and Alzheimer disease: Then correlation analysis showed 10 genes were key genes associated with M1 macrophages and AD, of which ARMCX5, EDN3, GPR174, MRPL23, RAET1E, ROD1, TRAF1 and WNT7B were positively associated with M1 macrophages and AD, while OR4K2 and ZNF543 were negatively associated with M1 macrophages and AD (Figure 7B).