Starting with the observation that IL-6 and/or MYC-driven B cell and plasma cell tumors in BALB/c mice exhibit constitutive NF-κB/STAT3 activity that leads to up-regulation of NF-κB target genes, we found that two genes of this sort, CDKN1A and FANCD2, are important for human BL and human MM, respectively. This evidence concerns the gene STAT3 and plasma cell neoplasm.