NOTCH1 nonsynonymous mutations were associated with class-switched and IgA B cells in BRCA ER+ tumors (estimate = 10.6, adjusted P = 0.003), and nonsynonymous mutations in DGRC8 were associated with enriched IgA B cells in lung adenocarcinoma (estimate = 18.7, adjusted P = 0.04). This evidence concerns the gene CD79A and lung adenocarcinoma.