you should probably look at oncogenes in general.
https://en.wikipedia.org/wiki/Oncogene
at the simplest level, the particular gene, and particular perturberance, sets the "type" of cancer.
there will most often be additional genetic abnormalities giving nuance to the character of the oncotype.
the tumour is originated from a cell type of specific differentiation, and developmental potency, further widening the pool of possible cancer type.
immunotype of cancer also sets the relationship between cancer and the body.
the cells of the body are setup for a functional death and replacement so when you try to rescue a particular cell [or cohort] you are fighting against how the grand scheme of tissue maintenance operates.
unless you have concern for a particular long lived cell, it is best to destroy the tumour cell, and let the next cells in line replace them.
it is still a multifacet strategy being developed, inhibit the genetic properties of the tumour, and target the immunotype for destruction.