Creatine kinase-BB in the cerebrospinal fluid as a marker of CNS metastases and leptomeningeal carcinomatosis in patients with breast cancer.

To determine whether creatine kinase-BB isoenzyme would be useful in detecting central nervous system metastases secondary to breast cancer, we measured the cerebrospinal fluid (CSF) activity of creatine kinase (CK) and its BB isoenzyme (CK-BB) in 65 consecutive patients suspected of having CNS involvement.