MMP9 and neoplasm: Carnosine was also shown to inhibit KRAS-mediated HCT116 proliferation [14], to inhibit metastasis of SK-Hep-1 invasive hepatocarcinoma cells by inhibiting expression and activity of matrix metalloproteinase 9 [47], and to eliminate tumor cells from a mixture of normal fibroblasts and HeLa cells [12].