A 50-year-old female (patient no. 8) who had advanced PTC with multiple lung metastases and a single large tumor mass (measuring 4.6 cm in maximal diameter) in the right lung showed low Tg and high anti-TgAb levels, which interfered with follow-up of the disease status based on Tg levels (Figure 5). The gene discussed is TG; the disease is neoplasm.