To assess the functions of NDUFA4L2 in ccRCC cells, we utilized a human ccRCC cell line RCC4 (RCC4-P) which expresses high levels of endogenous NDUFA4L2 in the presence of activated HIF-1α signaling.8 We first used CRISPR-Cas9 gene-editing technology to knock out (KO) NDUFA4L2 in RCC4-P (Figure 1a) and confirmed the NDUFA4L2 KO in the RCC4-KO-643 polyclonal cell line via amplicon next-generation sequencing (Figure 1b) and Western blotting (Figure 1c). This evidence concerns the gene COXFA4L2 and nonpapillary renal cell carcinoma.