In addition to NETs, leukotrienes derived from tumour-mobilized lung neutrophils aid the tumour colonization of distant tissues by selectively increasing the proliferation of metastasis-initiating tumour cells in a pERK1/2-dependent manner, and Zileuton, an inhibitor of leukotriene-generating enzyme Alox5, abrogates neutrophil pro-metastatic activity and consequently reduces metastasis [175]. This evidence concerns the gene ALOX5 and neoplasm.