INSM1 and medullary thyroid gland carcinoma: It was originally cloned as IA-1 in 1992 by Goto et al. from a human insulinoma subtraction library and has since been found to be expressed in a variety of neuroendocrine neoplasms, including insulinomas, medullary thyroid carcinomas, pituitary adenomas, and pulmonary neuroendocrine neoplasms [20,24,25].