Background: Bcl-2 staining positivity has shown limited prognostic value. However, we have decided to study this issue in the era of mammography screening, and adjuvant treatment protocols.
Methods: Paraffin sections of 414 breast cancers were stained for bcl-2 and staining intensity graded. Association of bcl-2 with established prognosticators was analysed with chi 2 test and odds ratios in 2 x 2 tables. Kaplan-Mayer analysis and Cox's regression were used to evaluate the prognostic value of bcl-2 and other prognosticators.
Results: Bcl-2 immunostaining was associated with tumor size, lymph node status, histological type, multivariate prognostic index, standardized mitotic index, Ki-67 fraction, DNA-index, proportion of cells with DNA above 5c, estrogen receptor status, and histological grade. ER status showed the best association with bcl-2 positivity (odds ratio 11.3, 95% CI 5.6-22.7). In the whole group of patients bcl-2 positivity was not an independent prognosticator. However, among N+ patients bcl-2 staining was significant, and among postmenopausal N+ patients bcl-2 immunostaining was a stronger independent prognosticator than tumor size.
Conclusions: The prognosis of N+ breast cancers can potentially be evaluated with bcl-2 positivity, in association with tumor size, and mitotic activity. Among postmenopausal N+ patients, most of whom have received anti-estrogen therapy, bcl-2 positivity is an independent prognosticator. Also, the close association of bcl-2 positivity with ER status supports the view that bcl-2 negativity reveals a patient group which might benefit from additional treatment in association with anti-estrogen therapy.