CA9 and NDUFA4L2 served as marker genes of ccRCC cells and they were distributed in clusters 4, 7, 8, 10, 11, 12, 15, which overlapped with the distribution of epithelial cell markers and this resulted from that ccRCC originates from renal tubular epithelial cells (Figure 10D). Here, CA9 is linked to nonpapillary renal cell carcinoma.