PS2 PROTEIN STATUS FAILS TO BE AN INDEPENDENT PROGNOSTIC FACTOR IN ANAVERAGE BREAST-CANCER POPULATION

In this study we analysed the cytosolic concentrations of the estrogen -regulated protein pS2 in tumors of 462 breast cancer patients, 16 ben ign breast tumors and 58 metastases. The median pS2 values were highes t in breast cancer, followed by benign tumors and metastases (Kruskal- Wallis Test: p<0.05). Information on other prognostic factors and clin ical outcome was available for 354 patients (median follow-up, 35 mont hs). We found a pS2 value of 2 ng/mg protein to be the best cut-off le vel to discriminate between pS2+ (63%) and pS2- (37%) tumors with resp ect to relapse-free survival (RFS) and overall survival (OS). The pS2 status was significantly correlated with age, estrogen receptor (ER) a nd progesterone receptor (PR) status. pS2 was negatively correlated wi th grading and was more often positive in invasive lobular than in inv asive ductal carcinomas. ER, pS2 and grading were highly significantly correlated with each other. In univariate analysis pS2- patients show ed a significantly shorter RFS (p=0.0001) and OS (p=0.0005). However, multiple regression analysis revealed that in our series of patients t he pS2 status provides no independent prognostic information.