Compared to primary lung cancer, all the expression of hub genes increased in lymph node metastasis samples, and the expression of BUB1, BUB1B, CDK1, CCNA2 and CDC20 were related to peritoneum metastasis (Figure 4C; Supplementary Figure S3C). The gene discussed is CDK1; the disease is metastatic malignant neoplasm in the lymph nodes.