Fig. 1
From: Chronic stress in solid tumor development: from mechanisms to interventions
Chronic stress regulates the tumor microenvironment through the neuroendocrine system. The nervous system is composed of cranial and spinal nerves. Under chronic stress, the hypothalamus releases CRH, which triggers ACTH secretion from pituitary to stimulate the secretion of glucocorticoids from the adrenal cortex. Chronic stress also activates the SNS, which directly innervates organs through sympathetic neurotransmitter norepinephrine (NE) release from neuro synapse, promoting the synthesis and secretion of epinephrine (E) from the adrenal medulla. NE generally reaches the TME through nerve fibers, and E/glucocorticoids (GCs) reach it through the blood