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. The gene discussed is STAT3; the disease is Miyoshi myopathy.