TNF and fibrosarcoma: According to this view, we found that extremely low, nontoxic doses of iso1Au/TNF or iso1Au/TNF + IL12, corresponding to 3–6 × 107 nanoparticles (equivalent to 5–10 pg of TNF), were sufficient to exert synergistic effects with doxorubicin in the WEHI-164 fibrosarcoma model.