AR and metastatic malignant neoplasm in the lymph nodes: The statistical analysis (odds ratio and 95% confidence interval, respectively) showed that there were 3 independent risk factors for extrathyroidal extension, including age (>55 y/o) (OR: 2.88, 95% CI: 1.15–7.2, p = 0.024); lymph node metastasis (OR: 8.56, 95% CI: 3.69–19.94, p < 0.001); and expression of AR (OR: 0.38, 95% CI: 0.17-0.89, p = 0.026), suggesting that AR expression is an independent factor for extrathyroidal extension in PTC (Table 3).