NPY2R and metastatic malignant neoplasm in the lymph nodes: Methylation of the HCRTR2 promoter significantly correlated with lymph node metastasis (P = 0.040), methylation of the NPY1R promoter significantly correlated with smoking status (P = 0.041), and methylation of the NPY2R promoter significantly correlated with age (P = 0.040) and recurrence (P = 0.004).