A previous study of chronic lymphocytic leukemia demonstrated that KITLG is an upstream moderator of the MAPK pathway.8 From the bioinformatics analysis of TCGA‐THYM and GEO‐GES29695 data, we found that the expression of KITLG was higher in type A and AB thymoma than in the other subtypes. The gene discussed is KITLG; the disease is B-cell chronic lymphocytic leukemia.