Analysis of Bcl-2 protein expression in chronic lymphocytic leukemia - A comparison of three semiquantitation techniques

A number of studies revealed that high expression of the proto-oncogene bcl -2 correlated with poor prognosis or resistance to chemotherapy in some tum ors but predicted a favorable clinical course in other neoplasias. In these studies, however, different immunologic techniques for Bcl-2 detection wer e used, raising the question of whether the methods applied were comparable . Using chronic lymphocytic leukemia (CLL) cells, the aims of our study wer e as follows: (1) to determine the reproducibility of Bcl-2 semiquantitatio n by immunocytochemistry, flow cytometry, or immunoblotting; (2) to study t he agreement between results obtained by these methods; and (3) to examine the association between Bcl-2 expression in tumor cells of 99 patients with CLL and clinical parameters. We found that determination of Bcl-2 expressi on by immunocytochemistry was reproducible and the results were comparable with those of flow cytometry and immunoblotting. In the patient collective examined, Bcl-2 expression did not reflect the extent of tumor mass, but hi gher levels were found more often in patients with progressive disease.