We knocked down TFAM to decrease the mtDNA copy number in several human cancer cell lines, including esophageal squamous cell carcinoma (ESCC) [42], renal cell carcinoma (RCC) [27], colorectal cancer (CRC) [43], and non-small cell lung cancer (NSCLC) [33] as well as GAC (Figure 2 & Supplementary Figure S3; Table 5) in the current study. Here, TFAM is linked to esophageal squamous cell carcinoma.