RT Journal Article SR Electronic T1 Multiple endocrine neoplasia type 2 andRET: from neoplasia to neurogenesis JF Journal of Medical Genetics JO J Med Genet FD BMJ Publishing Group Ltd SP 817 OP 827 DO 10.1136/jmg.37.11.817 VO 37 IS 11 A1 Hansford, Jordan R A1 Mulligan, Lois M YR 2000 UL http://jmg.bmj.com/content/37/11/817.abstract AB Multiple endocrine neoplasia type 2 (MEN 2) is an inherited cancer syndrome characterised by medullary thyroid carcinoma (MTC), with or without phaeochromocytoma and hyperparathyroidism. MEN 2 is unusual among cancer syndromes as it is caused by activation of a cellular oncogene, RET. Germline mutations in the gene encoding the RET receptor tyrosine kinase are found in the vast majority of MEN 2 patients and somaticRET mutations are found in a subset of sporadic MTC. Further, there are strong associations ofRET mutation genotype and disease phenotype in MEN 2 which have led to predictions of tissue specific requirements and sensitivities to RET activity. Our ability to identify genetically, with high accuracy, subjects with MEN 2 has revolutionised our ability to diagnose, predict, and manage this disease. In the past few years, studies of RET and its normal ligand and downstream interactions and the signalling pathways it activates have clarified our understanding of the roles played by RET in normal cell survival, proliferation, and differentiation, as well as in disease. Here, we review the current knowledge of the normal functions of RET and the effects of mutations of this gene in tumorigenesis and in normal development.