A more powerful approach for the treatment of tumours addicted to chronic active BCR signaling caused by genetic mutations upstream of BTK, such as those targeting the My-T-BCR complex (e.g., ABC-DLBCL of the MCD type, primary central nervous system lymphoma (PCNSL), and Waldenström Macroglobulinemia (WM)) emerged from the development of the small molecule ibrutinib. Here, BCR is linked to primary central nervous system lymphoma.