To unbiasedly identify the crucial factors produced by CSF, we utilized liquid chromatography-mass spectrometry (LC-MS) based label-free quantitative proteomic platform on the CSF, respectively collected in control and leptomeningeal metastasis mice. Cell-free CSF was collected from Ctrl or LM mice at day12 after LLC-LeptoM inoculation, followed by proteomics analysis. n=15 mice for three samples per group, CSF pooled from five mice per sample.