Introduction to the special section on neuroendocrine neoplasms

The endocrine system, a complex network of glands, orchestrates physiological balance within the body through the production and secretion of hormones. These hormones are chemical messengers in intercellular communication, acting as conduits between the secretory cells and distant target sites. They traverse the circulatory system by being released into the extracellular fluid, and their impact is specific to cells possessing receptors for a particular hormone.
The endocrine system collaborates...

Endocrine cells produce hormones to communicate with remote target cells found in other organs. The hormone reaches these distant areas using the circulatory system. This exposes the whole organism to the hormone but only those cells expressing hormone receptors or target cells are affected. Thus, endocrine signaling induces slow responses from its target cells but these effects also last longer.

The intricate framework of the endocrine system encompasses a diverse array of glands, with their target tissues and organs strategically distributed throughout the body. Central to this network are the endocrine glands, specialized structures that lack ducts and release hormones directly into the interstitial fluid. Notably, the hypothalamus, a vital neuroendocrine organ situated in the brain, governs neural functions and serves as a potent source of hormonal regulation. Near the hypothalamus...

A signaling cascade is a series of events that facilitates the transmission of information within or between cells, culminating in a targeted response in the recipient cell. As chemical messengers, hormones are pivotal in initiating and modulating these intricate signaling cascades based on their solubility.
Lipid-soluble hormones, such as steroid hormones, demonstrate an intracellular action. These hormones traverse cell membranes due to their lipid nature. Once inside the target cell, they...

The mammalian target of rapamycin or mTOR protein was discovered in 1994 due to its direct interaction with rapamycin. The protein gets its name from a yeast homolog called TOR. The mTOR protein complex in mammalian cells plays a major role in balancing anabolic processes such as the synthesis of proteins, lipids, and nucleotides and catabolic processes, such as autophagy in response to environmental cues, such as availability of nutrients and growth factors.
The mTOR pathway or the...

Neurotransmitters play a crucial role in the communication between neurons in the autonomic nervous system. Neurons in the autonomic nervous system can be cholinergic or adrenergic depending on the neurotransmitters synthesized. Cholinergic neurons use acetylcholine as their primary neurotransmitter. This includes all the preganglionic fibers of the sympathetic and pre- and postganglionic fibers of the parasympathetic nervous systems. In addition, neurons of the somatic nervous system also use...