Creatine kinase isoenzyme BB: a lung cancer associated marker

We investigated the diagnostic role of creatine kinase isoenzyme BB (CK-BB) in lung cancer. CK-BB was assayed using a radioimmunological system by saturation with Mallinchrodt double antibody 125I labelled (RIA Quant-CPK-BB). Sensitivity was 97% and specificity 90% in 44 cancers (T2-T3), in 36 non-cancers (chronic bronchitis) and in 48 healthy controls. Mean serum CK-BB values for patients with chronic bronchitis (2.64 +/- 1.1 ng/ml) were virtually the same as in normal subjects. Patients with lung cancer had markedly higher serum CK-BB values (9.17 +/- 2.6 ng/ml) than either the control group (healthy subjects) or the chronic bronchitis patients (p less than 0.01). These results lead us to suggest that CK-BB serum determination might prove useful in screening pulmonary disorders. However, further studies are essential to establish: 1) the relationship between serum levels of the isoenzyme and the histology and stage of the neoplastic disease; 2) the relation between CK-BB and the aggressive potential of the neoplastic clone.