Tumour markers in breast cancer: a report on the extensive clinical use of B5 and CA15.3

Abstract

The B5 antigen is an integral component of human erythrocyte membranes which becomes enhanced in cancer patients. Here we have measured the correlation between B5 status and disease status in 456 patients with breast cancer. A B5-positive status was found in 45/335 (13%) of patients who were long-term disease free and without recurrence (group A), and in 12/53 (23%) of patients who were disease-free following recurrence (group B). In contrast, the majority of patients with progressive disease were B5 positive, including 27/41 (66%) with progressive relapsed disease (group C) and 21/27 (78%) whose disease was progressive from diagnosis (group D). In a similar analysis of CA15.3 in 289 patients, abnormally high marker levels were found in 1/210 group A; 1/35 group B; 20/29 group C; and 8/15 group D patients. Changes in B5 level showed a high correlation with disease behaviour: rising B5 levels occurred in 56 patients, of whom 50 (89%) were found to have recurrent disease. A decrease in B5 was associated with remission in 53/55 (96%) patients. CA15.3 is a marker for breast cancer which related to tumour bulk, and combination of CA15.3 with B5 increased sensitivity for active disease as 21/24 (88%) of patients with recently relapsed disease were positive for either B5 or CA15.3: 16/24 (67%) of these patients had a positive marker result at, or prior to, clinical diagnosis of their recurrence. Overall, the combined use of CA15.3 and B5 gave clinically relevant data which was more informative than either marker alone.