To confirm this hypothesis, we performed flow cytometry analysis and identified a striking abundance of CD19+ B cells in tumor lesions of MPR patients compared with treatment-naive and non-MPR patients (Fig. 2A, B, Supplementary Fig. S2A, B), and this proportion of CD19+ B cells were positively correlated with therapy response, while there was no difference in nearest non-cancer tissues (N), LNs and P1. This evidence concerns the gene CD19 and cancer.