Expression of Bax in relation to Bcl-2 and other predictive parameters in breast cancer

Background: It has been suggested that modification of the physiologicalsusceptibility to induction of programmed cell death in transformedcells contributes to the pathogenesis of cancer. One of themajor regulators of cell death is the bcl-2 family. In breastcancer, altered expression of Bcl-2 has been described. Distributionof its counterpart Bax and the differential expression patternhave still to be evaluated. Patients and methods: Bax expression was investigated by immunohistochemistryin 122 primary breast cancers. Results were correlated withexpression of Bcl-2 and other variables of predictive value. Results: There was a positive association between Bax expressionand histological grading, (over)expression of c-erbB-1 and -2and proliferative activity. The correlation was most significantin cases where no concomitant Bcl-2 expression could be detected.In the same subgroup an inverse correlation with positivityfor estrogen (and progesterone) receptors was observed. Thepresence of Bax was not significantly associated with eithertumor type and size, nodal status or expression of c-erbB-3. Conclusion: Expression of Bax was coupled with negative histopathologicalfeatures, especially when expression of Bcl-2 was downregulatedconcomitantly. It may appear that alterations of the differentialBax/Bcl-2 expression pattern take part in deregulation of proliferationand loss of differentiation, thus playing an important rolein malignant progression. Bax, Bcl-2, breast cancer, prognostic factors