Near-absolute expression of the bcl-2 protein identifies a subgroup of stage II breast cancer patients with a most favorable outcome. Results of a clinicopathological study

The clinical relevance of quantitative assessment of tumor-tissue expressio n of the bcl-2 protein in operated stage II breast cancer was investigated in this study. Thirty-five cases were studied by immunohistochemistry for t he expression of bcl-2 protein and analyzed for disease outcome. One fourth (25%) of the cases were negative and 57% demonstrated near-absolute expres sion of the bcl-2 protein. No association was found between immunohistochem ical detection of the protein with age, hormonal receptor status and tumor grading other than between bcl-2 and estrogen receptor expression (p=0.01). An impressively positive impact of near-absolute expression of bcl-2 on cl inical outcome was identified. Our results provide evidence that quantitati ve assessment of bcl-2 expression constitutes a new approach in early breas t cancer With potential clinical implications. We consider that molecular s ub-staging of patients with stage Il breast cancer by level of bcl-2 expres sion provides additional important prognostic information and prompts for i nvestigation of its clinical significance on the issue of adjuvant systemic therapy.