Can you "reformulate" your question because I do not understand it.
Some cancers metastasize to the brain like melanomas because of neurogenic factors. Not far from half of the brain metastases are from melanomas.
On the reverse, the brain can influence the growth of some primary cancers outside the brain with respect to various types of neuropeptides, an example of which is the CCK / gastrin family of peptides or also neurotensine.
I am providing you with attached articles, but I actually do not know whether I am responding within the field of your question.