Of these hub genes, only four genes, CDK1, NDC80, KIF11, and COL4A2, were shared between the two groups, whereas 189 hub genes from the normal group replaced 101 different hub genes from the tumor group, resulting in protein–protein network differences between the normal and tumor groups (Fig. 6 and Supplementary Table 9). The gene discussed is NDC80; the disease is neoplasm.