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: Pathology
Which of the following can be used as tumor marker in pancreatic carcinoma? 
Select and explain. 
A. CA-125, B. CA 27-29, C. CA 19-9, D. CA 15-3
C: CA 19-9
Answer: C: CA 19-9 
Explanation: CA 19-9 is a tumor marker for pancreatic as well as colon cancers.