Many pharmaceutical drugs currently in use bind to a specific “drug target” protein, and in that way alter the function

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Many pharmaceutical drugs currently in use bind to a specific
“drug target” protein, and in that way alter the function of this
target protein. Why is it complicated to apply this approach to
tumor suppressor genes for the treatment of cancer patients?
Group of answer choices
Because tumor suppressor genes are typically absent or
non-functional in cancer cells, removing the possibility of
modulating their function by drug binding.
Because most proteins encoded by tumor suppressor genes are
considered to be “undruggable” since they function based on
protein-protein interactions that involve interactions between
protein surfaces with a smooth shape.
Because there are many different tumor suppressor genes.
Because in cancer a number of different proteins are damaged and
targeting one of them does not have much effect.