PLK1 and glioma: Figure 6 showed the negative correlations between PLK1 mRNA levels and ESTIMATE score, Immune score and Stromal score in GBM, suggesting low immune pressure in PLK1 overexpressed patients (Figures 6A–C). Quksza et al. conceive a model to elucidate that low immune pressure induces high tumor heterogeneous and tumor mutational burden (TMB). We therefore hypothesized that this low immune pressure would induce tumors much more heterogeneous and TMB in PLK1 overexpressed patients (43), which was consistent with our analysis results in many tumors including glioma (Figure 6D).