In the validation cohort, further RT-PCR was performed to validate 4 DEGs specific for poorly differentiated HCC, of which NOVA1, NSMCE2 and KIAA0196 were significantly up-regulated, while AQP9 was significantly down-regulated in poorly differentiated samples, as compared with that in 9 adjacent non-tumor samples, 3 moderately differentiated samples and 3 well differentiated samples. Here, AQP9 is linked to hepatocellular carcinoma.