Expression of differentiation antigens within human mammary tumours is related to response to endocrine therapy and survival

Breast cancer cell-associated endopeptidase EC 24.11 modulates proliferative response to bombesin

We have investigated the production, growth and inactivation of gastrin-releasing peptide (GRP)-like peptides in human breast cancer cell lines. Radioimmunoassay detected GRP-like immunoreactivity (GRP-LI) in T47D breast cancer cells but not in the conditioned medium, indicating rapid clearance. No GRP-LI was found in the ZR-75-1 or MDA-MB-436 cells or their conditioned medium. High-performance liquid chromatography (HPLC) analysis of the GRP-LI in the T47D cells revealed a major peak, which co-eluted with GRP(18-27), and a minor more hydrophilic peak. In vitro stimulation of T47D cell growth by bombesin (BN) was enhanced to 138% of control levels (bombesin alone) by the addition of the selective endopeptidase EC 3.4.24.11 inhibitor phosphoramidon (0.1 ng ml(-1)). Fluorogenic analysis using whole cells confirmed low levels of this phosphoramidon-sensitive enzyme on the T47D cells. This enzyme, previously unreported in human breast cancer cells, significantly modulates both T47D growth and its response to BN-induced growth.

Prognostic value of a breast cancer-associated glycoprotein detected by monoclonal antibody LU-BCRU-G7

The immunohistochemical reactivity of a second generation murine monoclonal antibody (LU-BCRU-G7), raised against a novel fucosylated glycoprotein of M(r) 2300,000, has shown a significant association with prognosis of early stage carcinomas. Staining was observed in 72% of the 190 breast carcinomas tested. No relationship with steroid receptor status, stage or node status was found. An association with grade was observed (chi 2 7.83, 2 degrees of freedom, P = 0.02) only when the negative cut-off level was raised from < 10% cells staining to < 25%. Antibody reactivity was always cytoplasmic. Immunoblotting shows the antibody is reactive with a component of M(r) 230,000 not detected by HMFG 2. A significant association was found between lack of reactivity and improved disease-free interval (0.005 > P > 0.001) and survival (0.02 > P > 0.01). Subdivision of cases on the basis of node status showed that staining could refine survival data. A decreased reactivity of LU-BCRU-G7 was observed after pretreatment with beta-galactosidase but not a sialidase or beta-N-acetylhexosaminodase indicating that non-reducing terminal galactose residues in beta 1-3 or beta 1-4 linkages may be involved in the antibody binding site. This approach has identified a useful and novel prognostic marker in early stage human breast carcinoma.

Immunohistochemical reaction to human milk fat globule antibodies and breast cancer differentiation

Immunohistochemical studies of human breast cancers using human milk fat globule (HMFG) antibodies are divergent regarding the association with histologic differentiation. To clarify this association 392 tumors were assessed using two antibodies, HMFG-1 and HMFG-2. In half the tumors studied the tissue reaction to both antibodies was the same and in 63% the site of reaction was identical. Using both univariate and multivariate statistics, a highly significant association was recorded between membrane staining and well differentiated cancers and cytoplasmic staining and poor differentiation. Well differentiated tumors contained significantly more reactive cells. Complementing these findings was the association between age at diagnosis, tumor stage, and estrogen receptor status and differentiation. It is possible that immunohistochemical analysis with HMFG antibodies will provide better characterization of tumor differentiation than morphologic interpretation.

Assessment of milk fat globule membrane antibodies and lectins as markers of short-term prognosis in breast cancer

The milk fat globule membrane antibodies HMFG1, HMFG2, NCRC 11 and four of the Mam 6 series, and the lectins peanut agglutinin, wheat germ agglutinin, Concanavalin A, Lotus tetragonolobus and Ulex europaeus I have been applied to 115 stage I and II breast carcinomas (median follow up = 36 months) to assess their value as prognostic markers. Of the milk fat globule membrane antibodies only NCRC 11 staining showed a relationship to development of recurrent disease and overall survival, but this did not act as an independent indicator over and above that provided by histological grade. None of the lectins gave prognostic information, including those whose binding related to node status or grade. It is concluded that for short-term prognosis none of the markers can given independent prognostic information over and above that provided by histological evaluation.

The significance of hormone receptors to predict the endocrine responsiveness of human breast cancer

The paper reviews clinical data on the correlation between the response of human breast cancer to endocrine therapy and the tumour cell content of receptors of e.g. oestrogen (OeR), progesterone (PgR), androgens (AR) and the epidermal growth factor (EGFR). In advanced disease there is a well established correlation between OeR content and the rate of objective response to all types of endocrine therapy. However, if selection of first-line salvage therapy based on OeR status will result in prolonged survival or improved quality of life remains controversial. Assays of PgR, AR, and EGFR--in addition to OeR--increase the predictive ability but no study has been able to define an entirely unresponsive subgroup of patients on the basis of receptor status. In the adjuvant setting conflicting relationships have been reported. Some authors have found a benefit with tamoxifen also among OeR negative patients whereas others have concluded that adjuvant tamoxifen is ineffective in such patients. Prospective randomized trials are warranted to further assess the predictive value of hormone receptors, particularly in view of the increased frequency of thrombotic events and endometrial cancer associated with long-term adjuvant tamoxifen.

Circulating tumor marker levels in advanced breast carcinoma correlate with the extent of metastatic disease

The importance of the extent of metastatic disease in the circulating levels of CA 15-3 and carcinoembryonic antigens (CEA) was studied in 173 patients with advanced breast carcinoma. Estimates of the extent of metastatic disease were obtained by an objective arbitrary scale. Patients were observed clinically after serum samples were obtained, and survival was recorded. Elevated values of CA 15-3 (greater than 40 U/ml) were seen in 130 patients and CEA values (greater than 5 ng/ml) in 97 cases (75% versus 56%, P less than .0001). Elevated CA 15-3 values correlated with the estimated extent of metastatic disease (P less than .0001), number of metastases (P = .0006), and survival from study entry (P = .01). Elevated CEA values correlated with extent of disease (P less than .0001), but not with the number of metastases or with survival. No correlation was found between the elevated values of CA 15-3 or CEA and age, menopausal status, and initial tumor size or nodal status. The combination of the elevated values of CA 15-3 and CEA was more sensitive than CA 15-3 alone (P = .04), but there were no significant improvements when subgroups were considered. Significant differences, that depended on which specific organ was affected dominantly by metastases, were seen in the mean levels of CA 15-3 antigen. Similarly, patients with liver involvement had higher mean levels of CA 15-3 than those without hepatic metastases. A stepwise regression analysis of the dominant site of metastases, liver involvement, and estimated extent of disease showed that only the latter parameter retained a significant correlation with CA 15-3 antigen levels (P less than .0001). Median survival of patients who showed abnormal CA 15-3 levels was significantly shorter than that of patients with nonelevated CA 15-3 (10.1 versus 18.0 months, P = .04). This difference was not appreciated with CEA levels (10.2 versus 12.2 months, P = .4). We conclude that tumor marker levels in patients with advanced breast carcinoma correlate with the extent of metastatic disease. In addition, the CA 15-3 assay is more sensitive and correlates more accurately with the extent of disease than CEA. Finally, the observed CA 15-3 differences by organ involvement are related to the extent of disease variations. The objective evaluation of the extent of metastatic disease provides a new approach in the study and comparison of breast cancer-associated tumor markers.