CA 15-3 False Positives (correction)

I had an interesting discussion with my wife's onc recently as she was scratching his head over a gradually climbing set of ca 15-3 figures. She mentioned that there had been a spate of these recently and that they went up, then seemed to disappear.

I found this article.

http://www.ncbi.nlm.nih.gov/entrez/query.f...t_uids=15386335

'The neutrophil, not the tumor: serum CA 15-3 elevation as a result of granulocyte--colony-stimulating factor-induced neutrophil MU1C overexpression and neutrophilia in patients with breast carcinoma receiving adjuvant chemotherapy.'


It suggests that the use of g-csf (granulolyte - colony stimulating factor) treatments to counteract neutropenia (low white cell count) can boost the results of the ca 15-3 marker tests due to the expression of a MUC1 protein on the white cells produced.

As the use of these (expensive) treatments is becoming more common and they are being applied more widely in a preventative way (plus new generation g-csf's like Neulasta relased in 2004 being a lot more effective) I wondered if this might be the explanation.

The onc thinks it's a reasonable theory - though recognises that 15-3 can be a particularly flaky and non-specific marker which varies for numerous reasons. I know how a set of fluctuating marker results can set the heart racing and if other people are on g-csf's and have experienced the same problem without an explanation, I thought this might be of interest.

John, I get the CA 27-29 done. I have never had the 15-3 done. What are the circumstances under which the 15-3 is indicated as a diagnostic tool?

John L.

I had a false postive CA 27-29 as well as elevated liver enzymes when receiving Neulasta. The liver enzymes and CA 27-29 went back to normal about 6 weeks after I has my last Neulasta injection.

Barbara

ca 15-3 and ca 27.29 are effectively the same test for the same protein. 27.29 is the newer test. But being here in England we like to stick to our old world traditions and still use 15-3!

As both detect the MUC1 proteing, I suspect that the effect on the readings are the same for both tests. Interesting to hear someone else onserved the same effect.