Papillary thyroid carcinomas (PTCs) measuring 1.0 cm or less in diameter were defined as papillary thyroid microcarcinomas (PTMCs) by the World Health Organization (WHO), emphasizing on their benign behavior, probably of little clinical significance, which do not affect patients' survival. However, some reported that PTMCs may have aggressive behavior, can cause locoregional recurrences, cervical lymph node metastases, and even distant metastases. But till now, the characteristics of PTMCs with early lateral neck node metastasis were only reviewed and described by the clinicopathological parameters, and no analysis of PTMCs by the gene level is available. In these study, we investigate the genetic expressional alteration which influenced on the early lateral neck node metastasis in thyroid papillary microcarcinoma.