Research published in 2026 demonstrates that breast cancer disrupts the body's natural glucocorticoid diurnal rhythms by altering brain activity. Specifically, tumors trigger aberrant hypothalamic neuronal activity in the paraventricular nucleus, leading to a "flattened" hormone cycle that correlates with higher mortality and suppressed immunity. The study reveals that disinhibition of PVN CRH neurons is the primary neural mechanism behind this systemic dysfunction. By using timed neuromodulation to restore normal rhythms, the researchers successfully boosted anti-tumor immunity and slowed cancer progression. These findings highlight the critical role of CD8+ T cells in communicating brain signals to the tumor site. Ultimately, the work identifies the HPA axis as a novel therapeutic target for treating breast cancer through circadian regulation.

References:

• Gomez A M, Wu Y, Zhang C, et al. Aberrant hypothalamic neuronal activity blunts glucocorticoid diurnal rhythms in murine breast cancer[J]. Neuron, 2025.