Parity and lactation induce T cell mediated breast cancer protection
Menée à l'aide de modèles murins et d'échantillons tissulaires issus de patientes, cette étude met en évidence un mécanisme par lequel la gestation et l'allaitement réduisent le risque de cancer du sein ou la croissance tumorale en favorisant l'accumulation de lymphocytes T CD8+ dans les glandes mammaires
Parity and breastfeeding reduce the risk of breast cancer, particularly triple-negative breast cancer (TNBC)1,2, yet the immunological mechanisms underlying this protection remain unclear. Here, we show that parity induces an accumulation of CD8+ T cells, including cells with a tissue-resident memory (TRM)-like phenotype within human normal breast tissue. In murine models, pregnancy followed by lactation and involution drove the accumulation of CD8⁺ T cells in the mammary gland, coinciding with reduced tumour growth and increased intratumoural immune cell infiltration, effects that were abrogated by CD8⁺ T cell depletion. Importantly, this CD8+ T cell dependent tumour control was only observed following a complete cycle of lactation and involution. Consistent with this, primary TNBCs from parous women exhibited greater T cell infiltration and improved clinical outcomes. Together these findings, spanning preclinical models and over 1000 patient samples, provide new insight into how reproductive history shapes breast immunity, positioning CD8⁺ T cells as key mediators of parity-associated protection and informing novel strategies for both prevention and treatment of breast cancer.
Nature , résumé, 2025