I know a lot about Cholangiocarcinoma. I could write you novels about its link to Ulcerative Colitis, to primary sclerosing cholangitis. Steps to excise the bile ducts. Really all of this information is available online, so its not going to prove to you or anyone that I am what I claim to be.
What I will tell you is... Tumor markers are rarely if ever used in DIAGNOSIS.
Perfect example- With cholangio your CEA and CA-19-9 CAN be elevated... CAN BE.. I have seen people with Cholangio with NORMAL levels... I have seen people who DONT have cancer, who have high levels... So we dont check tumor markers to make a diagnosis.
They are used to follow up... For example, after surgery... If your CEA was say 20 preop... Postop week 4 it goes down to ZERO... But 3 months from now, it's back up to 20 or higher, we then can usually say that this tumor is coming back and that they aren't "cured"...
You wont find that on google, that's the real deal bro.
Add to this, certainly other routine labs like high Alk Phos, GGT etc can all help to aid in diagnosis, but tumor markers really aren't all that fantastic. We still have a lot to learn about them.