Because our recent data show that PBF also modulates the function of the monocarboxylate transporter 8 (17), which regulates thyroid hormone efflux from the thyroid gland (24, 25), our collective findings suggest a fundamental role for PBF in normal thyroid physiology, albeit one that appears to be dysregulated in neoplasia. The gene discussed is SLC16A2; the disease is neoplasm.