We found that circRNAs are significantly downregulated in BRCA (P=4.71e–32), CRC (P=9.50e–35), GC (P=5.09e–10), HCC (P=1.86e–32) and PRAD (P=1.52e–08) tumours, and upregulated in BLCA (P=1.13e–09) and KCA (P=3.65e–79). The gene discussed is CSN3; the disease is gastric cancer.