Abstract P3-01-03: Circulating tumor cells (CTCs) with epithelial to mesenchymal transition (EMT) phenotype are associated with inferior outcome in primary breast cancer
Authors: Mego M , Jurisova S , Karaba M , Minarik G , Benca J , Sedlackova T , Pindak D , Cristofanilli M , Reuben JM , Mardiak J 
Published: May 2019

Background: CTCs comprise heterogenous population of cancer cells with different clinical and biological value. Epithelial-mesenchymal transition (EMT) leads to generation of cells with cancer stem cell properties and increased resistance to chemotherapy and radiation therapy. While the prognostic value of CTCs with epithelial phenotype was repeatedly demonstrated in primary as well as metastatic breast cancer, prognostic value of CTCs with EMT phenotype (CTC_EMT) remained unknown. The aim of this study was to evaluate the prognostic value of CTCs with EMT phenotype in primary breast cancer (PBC) patients.

Methods: This study included 432 primary breast cancer patients treated by surgery and adjuvant therapy from March 2012 to February 2015. CTC_EMT were detected before surgery by quantitative RT-PCR assay. Peripheral blood mononuclear cells (PBMC) were depleted of hematopoietic cells using RossetteSepTMnegative selection kit. RNA extracted from CD45-depleted PBMC was interrogated for expression of EMT transcription factors (TWIST1, SNAIL1, SLUG, ZEB1) by qRT-PCR. Patient samples with higher EMT genes transcripts than those of healthy donors (n=60) were considered as CTC positive. Herein, we report the impact of CTC_EMT on disease-free survival (DFS).

Results: CTC_EMT were detected in 76 (17.6%) patients. Patients CTC_EMT had significantly inferior DFS compared to patients without CTC_EMT (HR = 2.46, 95%CI 1.29 – 4.68, p = 0.0003). Estimated 2- and 5-year DFS for CTC_EMT negative vs. CTC_EMT positive patients was 93.4% and 85.5% vs. 86.9% and 58.1%, respectively. Prognostic value of CTC_EMT was demonstrated in all subgroups of patients, most pronounced in hormone receptor positive, HER2 negative subgroup. In multivariate analysis, presence of CTC_EMT, axillary nodal involvement and hormone receptor status were independently associated with DFS (Table 1).Presence of CTC_EMT was not associated with any patients/tumor characteristics except p53 status (CTC_EMT were present in 20.7% of p53 negative vs. 12.4% p53 positive tumors, p = 0.04).

Conclusions: In this translational study, we demonstrate for the first time the prognostic value of CTC with EMT phenotype in primary breast cancer. Presence of CTC_EMT could lead to better identification of patients with increased risk of recurrence, especially in hormone receptor positive, HER-2 negative primary breast cancer patients.

Multivariate analysis of factors associated with disease free survivalVariableHR (95%CI)P – valueCTC with EMT phenotype  Present vs. absent2.46 (1.48-4.10)0.0005N stage  N+ vs.N02.92 (1.78-4.76)0.00001ER/PR status  Positive for either vs. Negative for both0.40 (0.23-0.71)0.001

Citation Format: Mego M, Jurisova S, Karaba M, Minarik G, Benca J, Sedlackova T, Pindak D, Cristofanilli M, Reuben JM, Mardiak J. Circulating tumor cells (CTCs) with epithelial to mesenchymal transition (EMT) phenotype are associated with inferior outcome in primary breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-01-03.