Fig. 6

POLA2 facilitates CRC progress by potential biological mechanisms. A and B POLA2 was differential expressed between CRC tissues and peritumor tissues from multiple independent databases, including our own CRC tissues, Oncomine database (Gaedcke CRC tissues: GSE20842, Hong CRC tissues: GSE9348, Skrzypczak CRC tissues: GSE20916) and TCGA/GTEx CRC tissues. The expression data of POLA2 was calculated by applying log₂(TPM+1) log-scale in a public dataset, and the expression levels of POLA2 were detected by qRT-PCR and normalized to that of GAPDH in our own CRC tissues. And P value was calculated by a two-sided Student’s t-test in TCGA/GTEx data, Hong CRC tissues, and Skrzypczak CRC tissues, whereas were calculated by a paired two-sided Student’s t-test in Gaedcke CRC tissues and our own CRC tissues. C Based on a genome-wide CRISPR-Cas9-based loss-of-function screen, POLA2 was essential for cell growth; high CERES scores meant POLA2 was essential for cell growth in 24 CRC cell lines. D POLA2 expression levels were evaluated in multiple tumor tissue types from the Oncomine database. E The effect of overexpressing POLA2 on colony formation ability in SW480 and HCT116 cells with three replicates. The results presented colony formation ability relative to the control group (set to 100%). Data were shown from three experiments and each with three replicates. ****P < 0.0001 was calculated by a two-sided Student’s t-test. F The effect of POLA2 overexpression on cell proliferation in SW480 and HCT116 cells. Results were presented as the means ± SD from three experiments with six replicates each. All **P < 0.01, ***P < 0.001 compared with controls were calculated by a two-sided Student’s t-test. G The protein interaction network of POLA2 by STRING database. H POLA2 and the top 4 target mRNAs were co-expressed in CRC tissues based on TCGA data. All P values and R values were calculated by Pearson’s correlation analysis