**10. Resistance to mAb**

Even if mAb therapy is successful, many patients show resistance to it. The resistance may be innate or acquired after exposure to antibodies. Natural resistance is already present in mutations in cancer cells prior to the therapy, and acquired resistance is received after the exposure to therapy [45]. Another limitation is the dependency of the therapy on the overexpression of receptors. Mutations of receptors and the components in the signaling pathway may decrease the efficacy of antibody-targeted therapy. If cells express a variant of the receptor, therapy's potency may still decrease even if the binding site does not change [46].
