How fasting boosts breast cancer therapy

Estrogen receptor-α (ERα) activation has been linked to breast cancer development and progression and endocrine therapy is been used to treat these patients. 

Studies have shown that periodic fasting enhances the efficacy of standard endocrine therapy and delays acquired drug resistance but the underlying mechanisms is not well understood.

The researchers in this study show that the fasting epigenetically reprograms breast tumors, dramatically enhancing endocrine therapy with large-scale activation of glucocorticoid receptor (GR) and progesterone receptor signalling and concomitant reduction in the activity of activator protein-1 (AP-1) family members.

They also demonstrate that GR knockout hinders the anti-tumor effects of fasting and GR ligands recapitulates fasting effects.

Fasting-mimicking diet exhibited increased blood progesterone and cortisol concentrations in breast cancer patients.

https://www.nature.com/articles/s41586-025-09869-0

https://sciencemission.com/Fasting-boosts-breast-cancer-therapy