Androgen receptor (AR), E-cadherin, and Ki-67 as prognostic markers in triple-negative breast cancer (TNBC).

Abstract

1062 Background: TNBC is an aggressive subset of breast cancer (BC) with central nervous system and visceral metastatic involvement and it represents a molecular subtype without specific target therapy. Methods: This observational, retrospectivestudy included 45 TNBC. The aim of this study was to evaluate the expression of some molecular determinants such as the AR, E-cadherin and Ki-67 in relation to histological type, time to relapse and overall survival.Immunohistochemistry (IHC) was carried out on formalin-fixed paraffin-embedded tumor samples obtained from patients (pts) defined TNBC, since ER and PgR were 0% and HER2 negative (IHC score 0/1 or FISH not amplified). Results: Median age was 58.8 years (range 39-77). The main histological type was ductal in 35 pts (77.7%), lobular in 7 (15.5%), medullary in 3(6.6%). 29 pts (64.4%) had a G3 tumor. Tumor stage was: I 6/45 (13.3%), IIA 21/45 (46.6%), IIIA 11/45 (24.4%), IIIB 3/45 (6.6%) and IV 4/45 (8.8%). All patients received treatments; the most frequently used regimens were anthracycline and taxanes. The androgen receptor was positive (IHC >10%) in 12/45 (26.6%). E-cadherin expression was semi-quantitatively analyzed according to the percentage of cells showing membrane positivity: 0 (0 to 10%); 1+ (10 to 30%); 2+ (30 to 70%); 3+ (> 70%). E-cadherin expression was considered positive if the score was ≥ 2, and negative when score was ≤ 1. This expression was negative in 24/45 (53.3%) cases. The Ki-67 index was ≥ 25% in 17/45(37.7%). The statistical analysis showed that patients with AR negative and Ki-67 positive expression have a significant correlation with the ductal histotype and G3 tumors (p < 0.001). Multivariate analysis showed that the patients with AR and E-cadherin negative but Ki-67 positive expression showed significantly (p < 0.001) worse overall survival time than those with either AR and E-cadherin positive but Ki-67 negative expression. Conclusions: Our data suggest that the combination of AR and E-cadherin expression as well as Ki-67 status might be useful prognostic markers in TNBC.