p27 Expression Correlates with Short-Term, but not with Long-Term Prognosis in Breast Cancer

New prognostic and predictive factors are needed to adjust more appropriate therapy for individual patients after operation. p27 is a cell cycle regulator, and a low tissue expression of this protein has been shown to correlate with poor prognosis in colorectal, lung, gastric, prostate, and breast cancer. In this study on 197 breast cancer patients with a median follow-up of 17 years, the prognostic value of immunohistochemical p27 expression was evaluated. After 5 years of follow-up patients with a p27 expression in less than 50% of the tumor cells had a significantly lower survival rate than those with an expression above this level (p=0.01). However, after longer follow-up the difference decreased and was no longer significant at 7 years (p=0.1) or when the entire follow-up period was examined (p=0.67). Tests for associations showed that a low p27 expression correlated with a high histologic grade, a high S-phase fraction (SPF), an advanced TNM stage and negative hormone receptor status. In conclusion: Tissue expression of p27 is a significant predictor of 5-year, but not of 10- or 15-year breast cancer specific survival.