Abstract P4-01-04: Circulating tumor cells (CTC) are associated with defects in innate and adaptive immunity in inflammatory breast cancer (IBC) patients

Abstract

Abstract Background: CTCs play a crucial role in tumor dissemination and are prognostic factor in primary and metastatic breast cancer patients. Immune cells in peripheral blood (PB) contribute to an unfavorable microenvironment for the CTCs survival. As such, effective host innate and adaptive immune surveillance systems could adversely influence tumor dissemination whereas dysfunctional immune systems could provide a favorable microenvironment for the dissemination of CTCs and cancer progression. This study aimed to correlate CTCs with the functions of innate [natural killer (NK) cells] and adaptive (T-cells) immune effector cells in PB of IBC patients. Methods: This prospective study included 65 IBC (21 non-metastatic, 14 de novo metastatic and 30 recurrent metastatic) patients treated between October 2008 and April 2012 at the MD Anderson Cancer Center. CTCs were enumerated before patients started a new line of chemotherapy using the CellSearch® system, 33 (50.8%) of patients were treatment naïve at the time of blood collection. The phenotype of T cells, their ability to secrete cytokines following activation through the T-cell receptor (TCR) and the NK cell subsets were analyzed by multiparameter flow cytometry and the results were correlated with CTCs and clinical outcome. For survival analysis immune cell counts were dichotomized to low or high category using the median count. Results: At least 1 CTC (≥ 1) or ≥ 5 CTCs per 7.5 mL of PB was detected in 40 (61.5%) or 21 (32.3%) of patients, respectively. Patients with at least 1 CTC or ≥ 5 CTCs had a significantly inferior overall survival (OS) [HR=2.48, p=0.003 and HR=1.85, p=0.045] than patients with no CTCs or with <5 CTCs, respectively. There was no correlation between CTCs count and total lymphocytes; however, patients with at least 1 CTC or ≥5 CTCs had significantly lower percentages of CD3+ and CD4+ T-cells compared with patients with no CTCs or < 5 CTCs, respectively. Patients with ≥ 1 CTC, had a lower percentage of TCR-activated CD8+ T-cells producing TNF-α (p=0.03) and IFN-γ (p=0.08), and a higher percentage of T regulatory lymphocytes (p=0.05) compared to patients with undetectable CTCs. Moreover, CTCs ≥5 was inversely associated with the percentage of the following NK cells subsets: non-ADCC NK (Spearman rho' = -0.30, p=0.02), ADCC NK (rho' = -0.15, p=0.20) and exhausted NK (rho = -0.24, p=0.04). We also observed increased prognostic value of CTCs in the context of adaptive immune cells, with worse OS for patients with ≥ 5 CTCs and low count of TCR-activated CD8+ T cells producing TNF-α (HR=6.72, p=0.0007) compared with patients with < 5 CTCs and high count of TCR-activated CD8+ that produced TNF-α. Conclusions: IBC patients with CTCs in PB had abnormalities in both innate and adaptive immunity as evidenced by low percentages of NK cell subsets, and low percentage of TCR-activated CD8+ T cells producing TNF-α, respectively. These data illustrate an inverse relationship between CTCs and both innate and adaptive immune cells in the PB microenvironment that could potentially impact tumor cell dissemination and initiation of the metastatic cascade. Moreover, immune cell profiling could add further prognostic value to CTCs in IBC patients. Citation Format: Michal Mego, Hui Gao, Evan N Cohen, Simone Anfossi, Antonio Giordano, Sanda Tin, Tamer M Fouad, Wendy A Woodward, Ricardo H Alvarez, Vicente Valero, Naoto T Ueno, Gabriel N Hortobagyi, Massimo Cristofanilli, James M Reuben. Circulating tumor cells (CTC) are associated with defects in innate and adaptive immunity in inflammatory breast cancer (IBC) patients [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P4-01-04.