Immortalized human embryonic kidney cell line HEK293 and the human embryonic lung fibroblasts HELF were used as positive control and negative control, respectively.

同时以端粒酶阳性的永生化人胚肾成纤维细胞HEK293作为阳性对照，以端粒酶阴性的人胚肺成纤维细胞HELF作为阴性对照。