Standard and molecular cytogenetics of endocrine tumors

Standard cytogenetic data are reported for benign and malignant thyroid and pituitary tumors. These identified chromosomal rearrangements activating RET and PPAR gamma 1 in a subset of papillary (PTCs) and follicular thyroid carcinomas (FTCs) and amplification of PKC epsilon in FTCs. Increases in complex karyotypes accompany progression in thyroid lesions. For pituitary tumors, karyotypic abnormalities more often affect functioning than nonfunctioning tumors. Such differences extend into comparative genomic hybridization (CGH), with a similar distribution for chromosomal imbalances. CGH data are reported on all varieties of endocrine tumors, supporting some cytogenetic findings and adding new hotspots for genomic imbalances. Increases in genomic imbalance accompany clinical progression in malignant thyroid tumors, adult adrenocortical tumors, parathyroid tumors, and some pancreatic endocrine tumors (PETs), e.g., insulinomas. Pheochromocytoma and FTC show more losses than gains. Specific patterns of imbalances are emerging for gastrointestinal PETs regarding location and hormone status; for pheochromocytomas, medullary thyroid carcinomas, and parathyroid tumors regarding genetic syndrome association; and for pituitary tumors regarding hormone status.