BMI1 and renal cell carcinoma: miRNA-218-5p was shown to be downregulated in a variety of carcinomas, including mesenchymal glioblastoma,24 pancreatic cancer25 and renal cell carcinoma,26 and exhibits tumor-suppressive activities,24, 25, 26, 27 while CCAT1 was shown to promote tumor progression.8 In the first place, we examined whether CCAT1 has any effect on miRNA-218-5p target genes and found that CCAT1 knockdown inhibited the expression of Bmi1 (Tu et al.27) and caveolin-2 (Yamasaki et al.26), whereas co-transfection of miRNA-218-5p inhibitor attenuated this inhibition (Figure 4a).