Don’t even think about it.

Top Line: While the interaction between cancer and the immune system steals all the headlines these days, the interaction between cancer and the nervous system is just as interesting...and disturbing.

The Studies: For instance, IDH-mutated gliomas are thought to produce large amounts of d-2-hydroxyglutarate that increase seizure activity. But what if chemical signaling between the brain and brain tumors went both ways? Two studies [1, 2] published in Nature last week independently describe the presence of neuron-tumor chemical synapses by which gliomas integrate into the neurochemical signaling structure of the brain. What happens when these synapses fire during brain activity? Just what you’d expect—a flood of glutamate induced tumor proliferation and invasion. Wait, what?! That's right, forget about cell phones. The very electrical activity of the brain itself communicates directly with tumor cells to promote tumor growth. On the flip side, reduced neuronal activity and inhibition of these synaptic receptors resulted in decreased tumor proliferation. In other words, what we are looking at here is the same tumor receptor-proliferation hallmark of cancer that we’re used to seeing outside the brain. What is more unsettling in this scenario is that brain tumors have integrated themselves into the essential electrical framework of our minds. But wait, a third study also demonstrated that brain metastases from triple-negative breast cancer also activate genes involved in neuron signaling to develop synapses with neurons in the brain

TBL: Primary brain tumors and brain metastases form chemical synapses with neurons whereby electrical activity in the brain contributes to tumor proliferation and invasion. | Venkataramani, Venkatesh, Zeng, Nature 2019