Next, we performed a statistical analysis of the data in the Gene Expression Omnibus (GEO) database (www.ncbi.nlm.nih.gov/geo/) and found that the expression level of CRL4 (DDB1/Cul4A) in ovarian tumors was higher than normal ovarian tissue (P < 0.05), which was consistent with the results of IHC staining (Fig. 1c). This evidence concerns the gene DDB1 and ovarian neoplasm.