Serum and tissue c-erbB-2 antigen levels predicts outcome and response to hormonal therapy of bone metastatic breast cancer

Bone metastases are considered oestrogen receptor positive and usually respond to hormonal therapy. Expression of the cerbB2 oncoprotein is claimed to predict cancers, which recur early and respond poorly to hormonal therapy. Aims: To detect whether raised serum levels of serum cerbB2 antigen predicts poor response to hormonal therapy as judged by UICC criteria and to determine the incidence of cerbB2 expression in primary tumours associated with bone metastasis. Methods: Preoperative serum levels of soluble HER-2/neu in 75 primary breast tumour patients and the sera of 56 patients with bone metastatic disease prior to change in hormonal therapy have been analysed by ELISA. Levels of≥25ng/ ml were considered significantly raised. In addition paraffin sections of 76 of the 131 women was retrieved and immunohistochemistry (IHC) performed using NCL-CBL11 (Novocastra) antibody to determine cerbB2 expression.Results: Expression of cerbB2 was seen in 37% of early tumours but no raised serum level ≥ 25ng/ml were seen. A correlation between serum levels of cerhB2 and tissue expression was seen (p<0.05) Factor Number cerbB2≥25ng/ml cerbB2(IHC) Responders 10 0 2/8(25%) Stable 22 0 4/13(31%) Progressive 24 14(58%)**10/15(67%)*IHC= Immunohislochemistry*p<0.05,**p<0.000 Conclusion: Forty five percent of the patients with bone metastases expressed cerbB2. Tumour expression of cerbB2 and raised serum levels of cerbB2 predicted response to hormonal therapy.