IMMUNONEUTRALIZATION OF GONADOTROPIN-RELEASING-HORMONE - A POTENTIAL TREATMENT FOR ESTROGEN-DEPENDENT BREAST-CANCER

The aim of this study was to assess the therapeutic potential of activ e immunisation with GnRH-glycys-PPD in a hormone-dependent experimenta l model. Mammary tumours were induced in female rats using dimethylben zanthracene (DMBA) and the effects of GnRH immunoneutralisation on tum our development were evaluated. High titres of anti-GnRH IgG correlate d with a decrease in oestrogen levels and subsequent tumour suppressio n. A comparison of immunised and non-immunised animals showed that whe n GnRH-specific IgG levels were at a maximum titre (80-100 mu g/ml), n early 10% of the GnRH-glycys-PPD treated animals showed mammary masses , compared with all the non-treated animals at the same stage in the s tudy. When the antibody levels fell, tumour regrowth was observed, but to a level below that observed in the non-treated animals. Following further treatment with the analogue, the tumours regressed again, show ing their retention of hormone dependency. This is consistent with oth er endocrine manipulations in the treatment of breast cancer; the adva ntages of immunisation with GnRH-glycys lies in its non-toxicity and r eduction in side-effects, which were mainly adjuvant-induced, (C) 1997 Elsevier Science Ltd.