Furthermore, to examine the direct functional effect of N2-neutrophil on brain metastasis in vivo, we performed gain-of-function N2-neutrophils (CD11b+Ly6G+) adoptive transfer isolated from bone marrow of naive, non-tumor-bearing Balb/c mice pretreated with nicotine for 10 days as previously described [37]. The gene discussed is ITGAM; the disease is neoplasm.