Characterization of the immune environment in pregnancy-associated breast cancer

Abstract

Pregnancy-associated breast cancer (PrBC) is a rare and clinically challenging condition. Specific immune mechanisms and pathways are involved in maternal–fetal tolerance and tumor-host immunoediting. The comprehension of the molecular processes underpinning this immune synergy in PrBC is needed to improve patients’ clinical management. Only a few studies focused on the immune biology of PrBC and attempted to identify bona fide biomarkers. Therefore, clinically actionable information remains extremely puzzling for these patients. In this review article, we discuss the current knowledge on the immune environment of PrBC, in comparison with pregnancy-unrelated breast cancer and in the context of maternal immune changes during pregnancy. A particular emphasis is given to the actual role of potential immune-related biomarkers for PrBC clinical management.

Plain language summary

Pregnancy-associated breast cancer (PrBC) affects about 4% of women with breast cancer who are of childbearing age. Managing these tumors is difficult due to interactions between the mother, fetus and tumor. These interactions cause changes in the immune system of patients with PrBC. Understanding how the immune system responds to PrBC may lead to better ways of managing the disease. This review focuses on the current knowledge of the immune system in PrBC, including which components can be used as biomarkers to improve clinical management.

Keywords::

• biomarkers
• breast cancer
• breast cancer during pregnancy
• pregnancy-associated breast cancer
• tumor immune microenvironment

Author contributions

Each author made substantial contributions to the conception and design of the work, and the draft and final approval of the submitted version.

Acknowledgments

The authors acknowledge support from the University of Milan through the APC initiative; the authors were partially supported by the Italian Ministry of Health with ‘RicercaCorrente’, ‘5 × 1000’; Konstantinos Venetis is supported by Fondazione IEO-MONZINO and Mariia Ivanova is supported by Fondazione Umberto Veronesi.

Financial& competing interests disclosure

The authors have no competing financial interests in relation to the work described. Outside of the submitted work, E Guerini-Rocco has received advisory fees, honoraria, travel accommodation/expenses, grants and/or nonfinancial support from AstraZeneca, Exact Sciences, GSK, Illumina, LCM Genect, Novartis, Roche and Thermo Fisher Scientific. N Fusco has received honoraria for consulting/advisory role from Novartis, AstraZeneca, Diaceutics, Adicet Bio and Sermonix; speaker bureau from MSD, Boehringer Ingelheim, Novartis, AstraZeneca, Daiichi Sankyo, GSK, Gilead and Diaceutics; and research grants from Novartis and Reply. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Additional information

Funding

The authors have no competing financial interests in relation to the work described. Outside of the submitted work, E Guerini-Rocco has received advisory fees, honoraria, travel accommodation/expenses, grants and/or nonfinancial support from AstraZeneca, Exact Sciences, GSK, Illumina, LCM Genect, Novartis, Roche and Thermo Fisher Scientific. N Fusco has received honoraria for consulting/advisory role from Novartis, AstraZeneca, Diaceutics, Adicet Bio and Sermonix; speaker bureau from MSD, Boehringer Ingelheim, Novartis, AstraZeneca, Daiichi Sankyo, GSK, Gilead and Diaceutics; and research grants from Novartis and Reply. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.