A method for treating B-cell lymphoma in a subject that has been diagnosed as having a B-cell lymphoma characterized by a mutation in MYD88 and is in need of such treatment is presented. The lymphoma is treated with an oligonucleotide having a sequence 5′-(CCT)n-3′. The B-cell lymphoma may be activated B-cell-like (ABC) subtype of diffuse large B-cell lymphoma (DLBCL) or Waldenstroms macroglobulinemia (WM).