Abstract
We previously reported that the expression on the primary tumour of the antigen CaMBr8 was related to a short survival, attributable either to higher tumour aggressiveness or a poor response to oophorectomy. To further verify the CaMBr8 prognostic value, we analysed retrospectively 862 breast cancer patients with a 19 year follow-up. In this series, CaMBr8 expression was found to be associated to some negative prognostic factors (premenopausal status, lymphnode invasion, a high number of mitosis and HER-2/neu oncoprotein expression), but had no influence on the patients' survival. Direct association with a poor prognosis was only evident in patients with lobular or mixed breast carcinoma, which however represent only a small fraction of the total breast cancers. Another possibility was that CaMBr8 could identify a subgroup of patients which did not respond to hormone therapy. To verify this hypothesis we evaluated on a second series of 116 patients the relationship between CaMBr8 expression and hormone-receptor levels. A negative association emerged which was also observed in vitro in the human breast cancer line MCF-7 treated with Sodium Butyrate, a differentiation inducer, which reduced hormone-receptor levels and increased CaMBr8 expression. In conclusion, the longer survival of CaMBr8 negative tumour patients observed in the initial study, was probably related to a better response to oophorectomy, due to the hormone-receptor level of their tumours.