However, in THP-1 cells co-cultured with A549 lung adenocarcinoma cells, the expression of p-STAT3, p-STAT6, and other markers significantly increased, suggesting that GM-CSF from A549 cells can suppress SHP2 in TAMs, thus activating the STAT3/STAT6 pathway and enhancing cathepsin secretion and M2 macrophage polarization. This evidence concerns the gene CTSS and lung adenocarcinoma.