Tumour markers?

Tumour markers?

Tumour markers? Hi,

Anybody know anything about tumour markers? I went for my first chemo today and before I started it they did a blood test and said it was to measure my tumour markers. Didn’t think twice about it at the time as my head was full of worrying about chemo, but now I’m curious. What is it about and what does it mean?

Any bright ideas appreciated!


For Yvonne Hi Yvonne,

I have found a web link which may be helpful to you regarding this question. The link is as follows:


I hope this is of help.

Kind regards.

BCC Forum Host

Hi Yvonne

My oncologist doesn’t do tumour markers as he doesn’t consider them reliable for everyone and prefers to keep an eye on things via scans.

I have attached below a great summary of why TMs work for some and not others - this has been provided by a non doctor on my US support group, but I think explains things pretty clearly.


Virtually every breast cancer (or any other kind of cancer) has certain structures on the surface of the tumor cells. If a particular
patient’s tumor has one or more structures that match up with what a particular tumor marker test looks for, that test can be used to monitor the patient’s progress, unsually only after diagnosed with a recurrence.

The concept of a lock and key pretty well explains things. The way the mechanism of action for tamoxifen, femara, and other selective estrogen receptor modulators (SERMs) and aromatase inhibitors (AIs) is usually explained to patients is that they block actual estradiol (the form of estrogen that hooks up with tumor cells and is presumed to cause ER+ and PR+ tumors to stop growing) from fitting itself into the receptors on PR+ PR+ the tumor cells’ surface. A similar process works for HER-2 positive tumors although the lock and key analogy works with antibodies and antigens.

A FISH test for HER-2 is extremely reliable; and IHC test for HER-2 is less reliable unless the test is evaluated by an EXTREMELY competitent lab technologist. Additionally, it is a FISH is a binary test. You either are or are not HER-2 positive.

The actual tumor marker tests, such as CEA, CA15-3 and CA27-29, can only identify the presence of tumor cells, IF and WHEN the receptor for that particular test is present. So, if a patient’s breast cancer tumor has the receptor for CEA, then the test should detect it and it probably can be used for monitoring after a recurrence is positively identified. Ditto for the other tests. Obviously, if the receptor for a particular test is not present on the surface of a patient’s tumor, then that particular test can’t be used to monitor that patient.