Moreover, we found that the C4 subpopulation highly expressed cystatin B (CSTB), matrix metalloproteinase 9 (MMP9), chemokine C-C ligand 5 (CCL5), and macrophage migration inhibitory factor (MIF) (Fig. 3F), which have the characteristics of promoting tumor cell migration and invasion. Here, MMP9 is linked to neoplasm.