Breast carcinoma with brain metastases: clinical analysis and immunoprofile on tissue microarrays

Background: Development of brain metastasis in patients with breast carcinoma correlates with poor outcome. Identification of tumor characteristics associated with breast cancer brain metastases (BCBM) could help identify patients at risk. Patients and methods: We studied 209 patients with BCBM. We evaluated a panel of proteins relevant to the biology of breast carcinoma on tissue microarrays of 133 primary tumors and 56 BCBM, including paired samples from 43 patients, and correlated the findings with the clinical outcome. Results: The median survival after BCBM diagnosis was 19 months (95% confidence interval, 13-23 months). Patients presenting with solitary metastasis had a significantly longer median survival than those with multiple lesions (25 versus 11 months, P <= 0.0001). We found no significant discordance in the expression of tested markers, but identified a possible association between the expression of basal cytokeratin CK5/6 in the primary carcinoma and the development of multiple rather than solitary brain metastases. Conclusions: Expression of antigens commonly associated with breast carcinoma does not differ significantly between the primary tumor and the corresponding brain metastases. Although no specific immunoprofile identifies breast carcinomas that develop brain metastases, we observed a possible association between CK5/6 expression in the primary tumor and multiple versus solitary BCBM.