A variety of tumor products (glycoproteins, enzymes, and hormones), as well as oncofetal and cell-surface antigens, have been used as tumor markers, ie, as sensitive (but nonspecific) tools to determine the presence of a tumor. One such marker is alpha-fetoprotein (AFP), a 70 000–molecular weight glycoprotein that is produced by the yolk sac, fetal liver, and intestinal epithelium. The circumstances that cause false elevations in the serum concentration of AFP are not completely certain.
In addition to decreased levels of thyroxine (T4) and triiodothyronine, hypothyroidism is associated with a variety of biochemical perturbations, including diminished urinary excretion of calcium, low serum concentrations of alkaline phosphatase and insulin-like growth factor I, and elevated serum concentrations of triglycerides and cholesterol.
A patient with hepatoblastoma, acquired hypothyroidism, and a persistent elevation in AFP prompted this investigation of the effect of hypothyroidism on serum concentrations of AFP in children.
Patient Report. A 15-month-old