To further explore the association of TOP2A mRNA expression level with the pathological stages of different cancers, the “Pathological Stage Plot” module of the Ualcan database (Figure 3F) was applied respectively, which revealed the highest mRNA expression of TOP2A in adrenocortical carcinoma, kidney chromophobe, kidney renal clear cell carcinoma, and lung adenocarcinoma appeared in stage 4, while in lung squamous cell carcinoma, head and neck squamous cell carcinoma and breast invasive carcinoma appeared in stage 3 (Figure 3F). Here, TOP2A is linked to squamous cell lung carcinoma.