MMP2 and neoplasm: In addition, we also observed that CM from astrocytes induced much less invasion of colon HCT116 tumor cells and almost didn’t induce invasion of non-metastasis breast MCF-7 tumor cells (Figure S5), which suggests that preferential substrates for MMPs (MMP-2 or -9) either in the tumor matrix or surrounding cells in the microenvironment is likely to contribute to different invasive ability.