Thyroglobulin messenger ribonucleic acid levels in the peripheral blood ofchildren with benign and malignant thyroid disease

Reverse transcriptase-PCR has identified thyroglobulin mRNA (Tg mRNA) in pe ripheral blood of normal adults and adults with thyroid cancer. However, no children were studied. The primary objective of this study was to determin e whether whole blood Tg mRNA levels differ between benign and malignant th yroid disease in children. The secondary goals were to determine whether wh ole blood Tg mRNA levels vary with age or pubertal development among childr en with thyroid disease. Whole blood Tg mRNA levels were determined in 38 c hildren (29 girls, nine boys; median age, 14.5 y; range, 4.8-20.4 y) with b enign and malignant thyroid disease and correlated with diagnosis, age, pub ertal status, thyroid size, and serum levels of free thyroxine, TSH, and Tg protein. Tg mRNA levels ranged from 3.3 to 104 pg Eq/mug total thyroid RNA (mean. 28 +/- 20.2 pg Eq/mug total thyroid RNA) and were similar in benign and malignant disorders (p = 0.67). However, in children with previously t reated papillary thyroid cancer, Tg mRNA levels directly correlated with to tal body I-131 uptake (p = 0.026) and serum Tg protein (p = 0.037). There w as no difference between boys and girls, and no change with pubertal matura tion. In children with benign thyroid disease, Tg mRNA levels correlated wi th serum TSH (p = 0.031), but not with diagnosis, age, Tanner stage, or thy roid size. We conclude that Tg mRNA levels are similar in children with ben ign and malignant thyroid disease and unchanged by age or pubertal status. but correlated with tumor burden in previously treated papillary thyroid ca ncer.