We also confirmed a high percentage of CA9+ and/or CD147+ expression, with an average of 84%, on the cell membrane of CTCs (DAPI+/CD45-) captured by CA9-/CD147-based enrichment approach in 94% (31 out of 33) samples we examined, which was accompanied by positive staining of CA9 and CD147 in the corresponding RCC samples as revealed by IHC (Figure 4A and Table 3). This evidence concerns the gene PTPRC and renal cell carcinoma.