By in vivo metastatic melanoma models, we found that enforced PEAK1 expression markedly increased lung metastatic nodes in the SKMEL19 cells, whereas targeting PEAK1 abrogated lung metastasis of SKMEL28 cells (Figure 4(a-b)), and few tumor masses could be seen in the lungs, suggesting that PEAK1 plays critical roles in melanoma cell metastasis. The gene discussed is PEAK1; the disease is neoplasm.