Breast cancer during pregnancy: from preclinical models to clinical studies

Breast cancer is the most common malignant disease among females worldwide and the leading cause of cancer related death. Especially during pregnancy, the incidence of breast cancer is on a continuous rise. Additionally, pregnancy-associated breast cancer is linked to a poor prognosis. It has been hypothesized that pregnancy related changes in the breast might delay a timely diagnosis. Further, hormonal changes and adaptational processes of the maternal immune systeme might simultaneously promote a tolerogenic microenvironment for the tumor. Therefore, we established a preclinical model that provides a prerequisite to comprehensively investigate the impact of the study maternal immune adaptations to pregnancy in modulating the severity of breast cancer during pregnancy.

Data available from our preclinical model revealed a significantly advanced tumor progression in pregnant mice, compared to non-pregnant controls upon inoculation of the murine breast cancer tumor cell lines Py8119 or E0771. Tumor progression was determined by caliper-based calculation of tumor volume, which was independently confirmed by end-of-experiment tumor volume assessment using CT scans. Mortality rates were similar between mouse groups, and confounding factors leading to mortality criteria, such as food and water consumption, could be excluded. Plug-to-pregnancy rate remained similar between tumor and non-tumor bearing pregnant mice, as well as serum progesterone levels. Litter size and fetal as well as neonatal weight remained unaffected between litters born by control or tumor-bearing females.

We further aim to initiate a multi-center longitudinal cohort study entitled PRINCEbreast, based in Hamburg, in which women diagnosed with breast cancer during pregnancy shall be recruited.

Publication History

Article published online:
11 October 2022