An assessment of the clinical usefulness of two serum markers, CA15 3 and HMFG 2 in localized and metastatic breast cancer.

CA 15 3 is a circulating glycoprotein defined by two monoclonal antibodies (115 D 8 and DF 3) with good specificity for breast cancer. Tumour-associated antigens have been detected by the monoclonal antibody HMFG 2 using a low pH ELISA method. We compare the values obtained using these two assays in patients with localized and metastatic breast cancer. CA 15 3 and HMFG 2 levels were measured in 61 patients, 24 localized and 37 metastatic, evaluated by standard biochemical and radiological testing. Of the patients with metastatic disease 78.4 per cent had an elevated CA 15 3 level whereas only 8.3 per cent of patients with localized disease had an elevated level (chi 2 = 28.2 p = 0.001); 29.8 per cent of patients with metastatic disease had elevated HMFG 2 levels while among those with localized disease 16.7 per cent had elevated levels (chi 2 = 0.57 p = NS). We conclude that only CA 15 3 is a useful marker in advanced disease.