Abstract P1-06-08: Stem cell markers CD44+CD24- and ALDH1 in primary breast cancers and metastatic sentinel and non-sentinel lymph nodes

Abstract

Abstract Background and Aim Studies of Aldehyde dehydrogenase 1 (ALDH-1) and CD44+/24- have suggested them as cancer stem cell (CSC) markers in breast cancers and the clinicopathologic and prognostic significance of these CSC markers have been widely investigated. However, expressions of CSC in metastatic axillary lymph nodes (ALN) of breast cancers have not yet been the center of interest. Therefore, the object of this study is to explore breast CSC markers CD44+CD24- and ALDH-1 in the primary breast tumor and metastatic ALNs by retrospectively analyzing the CSC expressions on metastatic tumor cells within ALN. Method 180 surgically resected breast cancers were selected and among them 165 cases had undergone sentinel lymph node (SLN) with or without non-sentinel lymph node (NSLN) dissections. 50 SLNs (30.3%) and 43 NSLNs (30.9%) had metastatic tumor cells and total of 74 cases were involved with axillary lymph node metastasis. Double immunohistochemistry of CD44/CD24 and single immunohistochemical staining of ALDH-1 were applied on paraffin embedded breast tissue specimens and lymph node specimens to evaluate the CSC phenotypes of primary tumor and metastatic lymph nodes. Results The prevalence of CD44+/CD24- and ALDH-1(+) tumor cells in primary breast cancer was 76.7% and 45.0%. In triple negative breast cancers (TNBC) contained significantly higher percentage (49.2%) of ALDH-1 positive tumor cells (p=0.001). CD44+/CD24- phenotype was present in 65.2% and 40.0% in metastatic SLNs and NSLNs, respectively. The analysis of metastatic sentinel lymph nodes and breast cancers with CSCs indicated that there are significant relationships with ALDH-1(+) (p<0.001) and CD44+/CD24- (p<0.001) phenotypes. CSC expression in metastatic NSLNs and breast tumors also showed significant association (p=0.001). However, CSCs in metastatic SLNs and NSLNs did not show any significant relationships to the intrinsic molecular subtypes. Conclusions This study investigated the impact of the stem/progenitor phenotype defined by CD44 positivity/CD24 negativity and ALDH-1 positivity in sentinel lymph nodes (SLN) on non-sentinel lymph node (NSLN) metastases. CSC phenotypes expressed in metastatic SLNs and NSLNs, independently showed significant association with the primary breast tumors. However, in future, the authors recommend that the exploration of a much larger study including a vast amount of pool will provide a more reliable result. Citation Format: Kim W, Kim Y-M, Kim W, Lee J-S. Stem cell markers CD44+CD24- and ALDH1 in primary breast cancers and metastatic sentinel and non-sentinel lymph nodes. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-06-08.