SUMO4 and ovarian serous cystadenocarcinoma: In contrast, the mRNA expression levels of SUMO4 in 22 tumor tissues, including colon adenocarcinoma (COAD), liver hepatocellular carcinoma (LIHC), and ovarian serous cystadenocarcinoma (OV), were lower than those in the corresponding non-tumor tissues; interestingly, however, the SUMO4 mRNA expression level in PAAD was still higher than that in the corresponding non-tumor tissues (Figure 1D).