The oestrous cycle stage affects mammary tumour sensitivity to chemotherapy.

ABSTRACT: The response of breast cancer to neoadjuvant chemotherapy (NAC) varies substantially, even when tumours belong to the same molecular or histological subtype¹. Here we identify the oestrous cycle as an important contributor to this heterogeneity. In three mouse models of breast cancer, we show reduced responses to NAC when treatment is initiated during the dioestrus stage, when compared with initiation during the oestrus stage. Similar findings were observed in retrospective premenopausal cohorts of human patients. Mechanistically, the dioestrus stage exhibits systemic and localized changes, including (1) an increased number of cells undergoing epithelial-to-mesenchymal transition linked to chemoresistance^2-4 and (2) decreased tumour vessel diameter, suggesting potenti

SUBMITTER: Bornes L 

PROVIDER: S-EPMC11666466 | biostudies-literature | 2025 Jan

REPOSITORIES: biostudies-literature