https://news.feinberg.northwestern.edu/2019/02/06/new-role-for-dopamine-in-deadly-brain-cancer/

"A Northwestern Medicine study has demonstrated how the deadly brain cancer glioblastoma exploits dopamine in order to evade treatment and fuel growth, and suggests that targeting the neurotransmitter may slow cancer progression."

Interestingly, melatonin supplementation decreases dopamine.