Notably, CM derived from tumor-promoting human M2 macrophages (stimulated with IL4 for 24 hours) resulted in the highest number of cancer cells (A549-GFP) in the tissue while CM derived from antitumor human M1 macrophages (stimulated with LPS and IFN-γ for 24 hours) resulted in a smaller number of cancer cells, both compared with TCS-PCLS treated with CM derived from naive human M0 macrophages (Figure 6F). This evidence concerns the gene IL4 and cancer.