In the subgroup analysis, we found that NEK2 overexpression was tightly related to worse OS of patients with HCC (HR = 1.50; 95% CI: 1.18–1.91; P < 0.01), CRC (HR = 2.03; 95% CI: 1.16–3.56; P = 0.03), glioma (HR = 3.15; 95% CI: 1.76–5.62; P < 0.01), lung cancer (HR = 2.04; 95% CI: 1.37–3.05; P < 0.01), breast cancer (HR = 1.52; 95% CI: 1.32–1.75; P < 0.01), and pancreatic duct adenocarcinoma (HR = 1.06; 95% CI: 1.01–1.12; P = 0.03) (Table 2). This evidence concerns the gene NEK2 and breast cancer.