CA27-29

I have read the following answer on this web site concerning CA27-29.  "Increased levels could be due to a variety of reasons such as - ovarian cysts, uterine fibroids, intestinal or colonic problems, medication; Paxil, hepatitis, tuberculosis, systemic lupus."  As I have Stage IV breast cancer (bone disease), and also have systemic lupus, can you tell me what exactly is meant by "increased levels?"  How high can these levels go due to the lupus?  Is 100-200 pt rise possible?  Because a person has lupus, is it possible that the CA27-29 reading will never return to normal?  Would the CA27-29 reading elevate during or due to a lupus flair?  Can you refer me to any pathology texts that might document the answers to these questions?  Thank you.

[CCF-RN,MSN-rf]

Dear snowy22:  We do not use the CA27-29 because we do not find it specific to breast cancer and cannot interpret the levels in situations such as yours.  How would one know, as you ask, whether an increase is due to breast cancer or lupus?  As such, I am unable to provide either an answer or a source for an answer to your question.