Endocrine system cells typically make up larger tissues and organs that function within and outside of the endocrine system. A hormone is any of a class of signaling molecules produced by glands in multicellular organisms that are transported by the circulatory system to target distant organs to regulate physiology and behaviour. Hormones have diverse chemical structures, mainly of 3 classes: eicosanoids, steroids, and amino acid/protein derivatives (amines, peptides, and proteins). The glands that secrete hormones comprise the endocrine system. The term hormone is sometimes extended to include chemicals produced by cells that affect the same cell (autocrine or intracrine signalling) or nearby
Multiple endocrine neoplasia mutation or hereditary transmission. The presence of two or more tumor types in a single patient does not automatically designate that individual as having MEN because there is a small statistical chance that development of two "sporadic" tumors that occur in one of the MEN syndromes could occur by chance. The term "multiple endocrine neoplasia" was introduced in 1968, but descriptions of the condition date back to 1903. Multiple endocrine neoplasia The term multiple endocrine neoplasia (MEN) encompasses several distinct syndromes featuring tumors of endocrine glands, each with its own characteristic pattern. In some cases, the tumors are malignant, in