MMP9 and cancer: Control of this system in cancer stem cells reduces proliferation and invasiveness by suppression of ERK and AKT pathways and down-regulation of MMP9 and octamer-binding transcription factor 4 (Oct-4).254 These effects on cancer stem cells support the possible use of antipsychotic drugs as co-adjuvants to existing therapy.255 Although further evidence is required to assure the role of dopamine receptors against CSC survival, this offers a new promise for cancer treatment.