This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Molecular Genetics, Subject name: Biochemistry
Which enzymatic mutation is responsible for immortality of cancer cells: 
Select and explain. 
A. DNA reverse transcriptase, B. RNA polymerase, C. Telomerase, D. DNA polymerase
C: Telomerase
Answer: C: Telomerase 
Explanation: Ans. C. Telomerase(Ref: Robbins 9/e page 288)Telomerase is one of several factors that contribute to the endless replicative capacity (the immortalization) of cancer cells.