MMP9 and neoplasm: Moreover, the LU-treated mice showed a decrease in MMP2 (matrix metallopeptidase 2) and MMP9 (matrix metallopeptidase 9) and a correlating increase in TIMP1 (TIMP metallopeptidase inhibitor 1) and TIMP2 (TIMP metallopeptidase inhibitor 2), but no significant changes in levels of these proteins were observed in Mel 1011-implanted tumours.