This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
All of the following statements are true about tumour markers except 
Select and explain. 
A. screening of a cancer, B. follow up of a cancer patient, C. confirmation of cancer, D. for knowing about recurrence
C: confirmation of cancer
Answer: C: confirmation of cancer 
Explanation: None