Cancer cells generally migrate in groups, called “collective cell migration”, during which tumor cells form cell scaffolds at the front of the migration site through cell adhesion molecules, such as integrins and calcineurin, to pull other cells forward, a process that requires the protein hydrolases MMP-14, MMP-2, and MMP-9 to play a role.101,102. The gene discussed is MMP9; the disease is neoplasm.