For type A and type B thymoma classification, seven protein classifier candidates identified in the previous discovery DIA experiments, including ACOT7, BCAM, FYB1, galectin‐3/9, GRAP2, and NKCC1, were selected in our PRM assay due to their significantly differential expression patterns between these two subtypes (Fig. 5A). The gene discussed is BCAM; the disease is thymoma.