BAFF-R expression in IgD+ CD24+ B cells was positively associated with lung adenocarcinoma (LUAD) risk (odds ratio [OR], 1.0168 [95% confidence interval [CI], 1.0006–1.0332]), mediated by macrophage migration inhibition factor (MIF) with a mediation proportion of 14.2% (95% CI, 0.00007–0.0046). The gene discussed is CD24; the disease is lung adenocarcinoma.