Page 50 - SDIR5 Abstract book 21 12 2021.

POSTER PRESENTATIONS

P10

The prognostic significance of interleukin-6 in hormonally dependent breast cancer

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Jelena Milovanović , Nataša Todorović-Raković , Jelena Hranisavljević , Marko Radulovic 1
1 Department of Experimental Oncology, Institute of Oncology and Radiology of Serbia, Belgrade, Serbia
2 Laboratory for Radiobiology and Molecular Genetics, Vinča Institute of Nuclear Sciences, Belgrade, Serbia

Background: Interleukin-6 (IL-6) is a pleiotropic cytokine with both pro- and anti-inflammatory properties.
This study aimed to investigate the prognostic significance of IL-6 and its association with the established
breast cancer parameters ER and HER2. Patients and Methods: The study included 79 premenopausal
women with early and locally advanced estrogen-dependent (ER+) breast cancer. All patients received
adjuvant hormonal therapy: tamoxifen alone (56/79) or combination with goserelin (23/79). The median
follow-up period was 85 months. IL-6 serum protein concentrations were measured by ELISA. Cox
proportional hazards regression analysis was implemented for prognostic evaluation of the data
categorized based on metastasis outcome. Results: IL-6 median serum concentrations were indicative of
their possible association with the actual metastasis outcome, as these values differed consistently
between patient groups with metastasis and without metastasis. Medians for IL-6 were 1.3, 1.7, 1.1, 1.5
and 2.1 pg/mL for the patients with metastasis on bones, brain, liver, lungs and without metastasis,
respectively. In the whole group of patients, IL-6 associated with good disease outcome (p=0.001,
HR=0.05). The median for IL-6 was 1.7 pg/mL in the group prognosticated as high-risk and 2.2 pg/mL in the
group prognosticated as low-risk. Multivariate analysis highlighted IL-6 as the independent prognostic
low
factor (p=0.001, HR=0.0007). IL-6 lost its prognostic significance in ER and ER high subgroups but IL-6
remained prognostically significant in both HER2− and HER2+ subgroups. Conclusion: Serum IL-6 is
indicated as a biomarker of favorable disease outcome. Clinical applicability of the study is based on its
relevance for the breast cancer immunotherapy research.
Keywords: breast cancer, inflammation, interleukin-6, metastasis, prognosis.

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