CXCR4 and nonpapillary renal cell carcinoma: Some of the genes such as ABCA13, CXCR4, ABCG2, EZH2, SALL4, and ALDH1A3 were significantly differentially expressed between the ccRCC tissues and normal tissues and showed a higher expression level in sphere cells than in the adherent cells (see later in Figure 3B).