Prognostic significance of immunohistochemical expression of Rb gene product in operable breast cancer

21121 Background: The aim of this study was to investigate the prognostic significance of the expression of Rb gene product in operable invasive breast cancer by performing immunohistochemical analysis. Methods: Between January 1993 and December 2001, 212 operable invasive breast cancer patients underwent immunohistochemical staining for Rb, and we retrospectively analyzed these results together with the clinical outcomes. Results: The overexpression of p53 was detected in 72.7% of the cases. The overexpression of Rb was correlated with positive hormonal receptor (p=0.000), and inversely correlated with lymph node metastasis (p=0.017) and vascular invasion (p=0.004). The tumor size, tumor histology, histologic grade, and tumor stage were not related to the overexpression of p53. Multivariate Cox regression analysis indicate that lymph node metastasis and tumor size were the significant prognostic factors for overall survival; lymph node metastasis was the significant prognostic factor for relapse free survival. On the subgroup analysis, the Rb expressors showed better 7-year overall survival (98.5% vs. 81.5%, respectively, p=0.005) and relapse free survival (94.1% vs. 77.4%, respectively, p=0.021) than did the p53 non-overexpressors for the patients without lymph node metastasis. However, for the patients with lymph node metastasis, the survival rates were not different for both the Rb expressors and the Rb non-expressors. Conclusions: Immunohistochemical staining of the Rb gene product was an independent prognostic factor for predicting survival of the lymph node negative operable breast cancer patients. No significant financial relationships to disclose.