TNF and papilloma: Reconstitution of DMBA/TPA-treated Rag2−/− mice with B cells from DMBA/TPA-treated WT mice restored papilloma growth, whereas reconstitution with B cells from DMBA/TPA-treated TNFα−/− mice failed to restore papilloma growth, thereby implicating TNFα-producing B cells as key mediators of tumorigenesis in this model.