The Human Embryonic Kidney (HEK) 293 cell line is widely used in research work such as vaccine production, adenovirus and adeno-associated viral vectors, and gene therapy. However, little attention was drawn to the passage level of 293 cells. We first claim that the tumorigenicity of the HEK 293 cell line reached 100% when the passage exceeded 65, whereas using low-passage (<52) HEK 293 cell line no tumor could be induced under the same condition. Results from nude mice assay, tumor tissue histological examination, primary culture, PCR and isoenzyme analysis showed that the tumor in nude mice could only be induced by viable high-passage 293 cells. This suggests that more attention should be paid to the passage level of the HEK 293 cell line, especially for vaccine production but the low-passage HEK 293 cell line should be acceptable to regulatory authorities for recombinant virus vector, vaccines, and gene therapy. Meanwhile, we also find that high-passage HEK 293 can be employed as a highly malignant tumor model as its tumorigenicity increases significantly.

中文翻译：

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体外培养的人胚肾293细胞系的致瘤性多样化。

人胚肾（HEK）293细胞系广泛用于研究工作，例如疫苗生产，腺病毒和腺相关病毒载体以及基因治疗。但是，很少引起对293细胞传代水平的关注。我们首先声称，当传代超过65时，HEK 293细胞系的致瘤性达到100％，而使用低传代（<52）HEK 293细胞系，在相同条件下无法诱导肿瘤。裸鼠试验，肿瘤组织学检查，原代培养，PCR和同工酶分析的结果表明，裸鼠的肿瘤只能由存活的高传代293细胞诱导。这表明应更加注意HEK 293细胞系的传代水平，特别是对于疫苗生产，但监管机构对于重组病毒载体，疫苗和基因疗法应接受低传代的HEK 293细胞系。同时，我们还发现，高通量的HEK 293可以用作高度恶性的肿瘤模型，因为它的致癌性显着提高。