INSM1 and pancreatic insulinoma: The expression of INSM1 was detected in early human fetal brain, endocrine pancreas development, and the tumors of NE origin including insulinoma, retinoblastoma, neuroblastoma, medulloblastoma, pheochromocytoma, Merkel cell carcinoma, medullary thyroid carcinoma, pituitary tumor, carcinoids, and small-cell lung carcinoma [1].