Although we could not detect spontaneous brain and lung metastases in our model, our results show that activity of MMP-2 and MMP-9 and angiogenesis were decreased in tumors developed in TNFR1 KO mice, suggestive of a pro-tumoral role of TNFR1 in melanoma progression. The gene discussed is TNFRSF1A; the disease is melanoma.