To test the hypothesis that pseudogene RACGAP1P may regulate the expression of its parent gene as a ceRNA, we firstly assessed the correlation of RACGAP1P and RACGAP1 via mRNA expression data derived from the TCGA, GEO (GSE5975, GSE76297) and Cancer Cell Line Encyclopaedia (CCLE) and found the co-expression patterns between RACGAP1P and RACGAP1 in primary HCC tissues, as well as HCC cell lines (Fig. 2a, b). The gene discussed is RACGAP1; the disease is hepatocellular carcinoma.