APOE and colorectal carcinoma: To explore the prognostic value of hub genes, we analyzed TCGA and GEO database on CRC patients and found that mRNA levels of CLU, SFTPD, CCL18, SPP1, APOE and BGN were upregulated at advanced CRC stages (Fig. 5A-F), while the expression of MMP3 was downregulated with the CRC stages (Fig. 5G).