We also observed the similar result when vectors were transfected into 293T cells (Supplemental Fig. S6).To further explore the relationship between E2F1 and CKS2, based on online tool GENPIA [31], which integrates RNA-seq data from the Cancer Genome Atlas (TCGA), we observed that both E2F1 and CKS2 were highly expressed compared to the normal tissues in 24 and 23 cancer types, respectively (Supplemental Figs. S7 and S8). Here, E2F1 is linked to cancer.