MMP9 and neoplasm: MMP9 expression is elevated and is correlated with poor prognosis in a wide array of tumors, including CRC [5, 6, 35–47], and it plays multiple roles in the process of tumorigenesis: MMP9 is produced by tumor cells as well as by stromal inflammatory cells such as tumor-associated macrophages (TAMs) and neutrophils, and is a key mediator of the tumor-stroma crosstalk that results in reciprocal activation of pro-oncogenic signaling in these two compartments [48–52].