There have been several recent advances in the understanding of the pr
ocess of carcinogenesis in the thyroid and parathyroid glands. The spe
cific abnormal molecules are, in many instances, well understood. This
review provides an overview of the molecules in the cell that regulat
e cell growth and proliferation and identifies the molecules that have
been found to be abnormal (or mutant) in various types of thyroid and
parathyroid neoplasia.