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Volume 3 Supplement 1

Abstracts of the Breast Cancer Immunotherapy Symposium (BRECIS): Sidra Symposia Series

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Towards targeting PD-1/PD-L1 axis in breast cancer, pre-clinical data

PD-L1 is a ligand that upon binding to its receptor (PD-1) on T-cells leads to T-cell anergy/and or apoptosis [1, 2]. We have shown that PD-L1 is expressed in breast cancer where its expression correlates with estrogen receptor (ER) negativity [3]. To understand the mechanism of the constitutive expression of PD-L1 in tumor cells of ER negative cells we used gene-in and out approach, large scale bioinformatics and immunohistochemistry. We have demonstrated that epithelial to mesenchymal transition (EMT) upregulates PD-L1 expression while cells expressing ER downregulates PD-L1, in parallel with reversal of EMT process. Bioinformatics analysis of gene expression signatures of breast tumors showed a significant correlation between EMT score and PD-L1 mRNA expression. Strikingly, very strong association were found between PD-L1 expression and claudin low breast cancer, a subset of breast cancer known to have high EMT score. In conclusion, we have characterized the expression of PD-L1 in breast cancer and we have demonstrated a strong association between PD-L1 expression, EMT status and claudin-Low breast cancer. Our finding will be essential for choosing the appropriate subset of breast cancer patients that will likely benefit from anti-PD-L1 targeted therapy and understand biological changes upon anti-PD-L1 therapy.

References

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This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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Ghebeh, H., Colak, D., Tulbah, A. et al. Towards targeting PD-1/PD-L1 axis in breast cancer, pre-clinical data. j. immunotherapy cancer 3 (Suppl 1), P7 (2015). https://doi.org/10.1186/2051-1426-3-S1-P7

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  • DOI: https://doi.org/10.1186/2051-1426-3-S1-P7

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