Answer:
The mutated protein would be the target for the new drug therapy.
Step-by-step explanation:
Cancer occur due to mutation in some important genes that regulate cell cycle as well as cell division.The mutation of tumor suppressor gene such as retinoblastoma,p53,PTEN etc also leads to the onset of cancer.
Now the most important point to note that mutation in the these particular genes result in the formation of abnormal proteins or disease causing proteins.These mutated proteins are the principle cause for the occurrence of cancer.
As a result the mutated protein would be appropriate target for the new drug therapy .The drug will interact with the mutated protein and blocks the toxic activity of the later.