Growth factor targeted and conventional therapy of breast cancer

Immunoassay for measuring the heparin-binding growth factors HARP and MK in biological fluids

Heparin-affin regulatory peptide (HARP) and Midkine (MK) belong to a family of growth/differentiation factors that have a high affinity for heparin. The involvement of these molecules in various proliferative diseases prompted us to develop an assay for measuring the concentrations of these factors in biological fluids and culture media. This report describes an immunoassay that uses only commercially available materials, based on the high affinity of certain molecules for heparin. It consists of adsorbing heparin-BSA covalent complexes to microtiter plate wells and to quantify the heparin bound HARP or MK by using appropriate antibody. The method is specific and measures concentrations ranging from 40-1200 pg/mL HARP and from 25-1200 pg/mL MK and various parameters are investigated. The within-assay coefficient of variation was less than 5% for both assays. The method was checked by measuring the concentrations of these growth factors in the sera of healthy humans and in patients with cancer. As previously reported, we confirmed that the serum concentrations of MK are higher in patients with tumours (n = 139) than in controls (n = 19). The synthesis of HARP and MK by various cells in culture was also analysed.

Prognostic value of epidermal growth factor expression in breast cancer

A series of 198 female breast cancer biopsies were analysed immunohistochemically for the expression of epidermal growth factor (EGF), with special emphasis on its prognostic significance. A total of 67/198 tumours (33.8%) were EGF-positive, 24 (12%) of which showed strong expression of EGF. EGF was usually expressed in the cytoplasm of the cancer cells but, in 22 cases, the normal ducts adjacent to the cancer showed positive staining as well. Strong EGF expression was related to distant metastases at diagnosis (P = 0.04). Oestrogen(ER)- and progesterone-receptor(PR)-negative tumours showed EGF positivity with equal frequency (P = 0.05 in both). Axillary lymph node status, histological type, tumour size, histological grade, S-phase fraction, mitotic index or cancer recurrence did not show any statistical correlation with EGF expression. Tumour size (P = 0.007), axillary lymph node involvement (P = 0.003) and ER content (P = 0.03) were independent prognostic factors in multivariate survival analysis, whereas EGF positivity, as an independent factor, had no effect on survival. In univariate analysis, however, EGF positivity predicted a more favourable outcome in axillary-lymph-node-positive tumours (P = 0.04). The results suggest that immunohistochemical assessment of EGF expression has hardly any clinical significance in addition to the well-established prognostic factors in breast cancer.

Effect of Decapeptyl (a GnRH analogue) and of transforming growth factor-alpha (TGF-alpha), in the presence of heparin, on the sulfatase activity of human breast cancer cells

The effects of the polypeptide Decapeptyl (a gonadotropin-releasing hormone (GnRH) agonist analogue) and of transforming growth factor-alpha (TGF-alpha), on estrone sulfate-sulfatase activities in the homogenates of various breast cancer cell lines were studied in the presence of heparin. In hormone-dependent MCF-7 breast cancer cells, Decapeptyl can inhibit sulfatase activity, and this effect is significantly augmented in the presence of heparin. In the other hormone-dependent T-47D breast cancer cell line, the decrease of sulfatase activity was only significant when Decapeptyl was associated with heparin. No significant effect on sulfatase activity elicited by heparin, Decapeptyl or a mixture of both was found in the hormone-independent MDA-MB-231 breast cancer cells. TGF-alpha stimulates sulfatase activity in the MDA-MB-231 cells but has no effect in the MCF-7 cells; in contrast, TGF-alpha combined with heparin provokes a decrease of the sulfatase activity in both cell lines. It is concluded that the sulfatase activity in some types of breast cancer cell can be inhibited by heparin combined with the polypeptides Decapeptyl or TGF-alpha.