You work in the pathology laboratory of a large metropolitan hospital and have been asked to assist with the screening of a biopsy sample from a patient$’$s cancerous tumor. You discover a mutation in the enzyme, inorganic pyrophosphatase, which is required to cleave pyrophosphate during DNA replication. The mutation reduces the enzyme$’$s activity by half. Would this mutation be beneficial or deleterious to the cells of the tumor? Explain your answer.