Thus, using immunohistochemistry (IHC) in combination with high-throughput RNA-sequencing (RNA-seq) or microarray data from The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), ArrayExpress and Oncomine databases, our study seeks to confirm the relationship among CDK5 expression levels and HCC development and progression. The gene discussed is CDK5; the disease is hepatocellular carcinoma.