Knowledge of the driver mutations underlying cancer has led to targeted therapeutics, such as the protein kinase inhibitor imatinib (trade name Gleevec) in cases of chronic myeloid leukemia. Cancer cells often become resistant to a given drug, so researchers continue searching for new drugs that target proteins that contribute to the cancerous phenotype. One recent promising approach uses drugs that lead to ubiquitination and proteasomal degradation of the target protein. Which of the following mutated proteins are good candidates for this approach?
A) oncogenes
B) proteins with loss-of-function mutations
C) proteins with gain-of-function mutations
D) tumor suppressor genes

Gain-of-function mutations: In biology, the term "gain-of-function mutation" is described as one of the different types of mutation in which the altered or changed "gene product" consists of an entirely new pattern or molecular function associated with gene expression. However, the "gene-of-function mutations" are being always considered as "Semidominant or Dominant".

In the question above, the correct answer is option C.