A Comparative Study on TERT Overexpression and CRISPR Editing Cell Immortalization Techniques

The boundary between a cancerous and normal cell is thin. As cancerous cells are caused by mutations from the accumulation of DNA lesions, it is important to look into the process of cellular transformation to find ways to develop controlled cell immortalization. (Yoshioka, 2015) There are many methods of cell Immortalization. The methods focused in this paper are TERT(Telomerase reverse transcription) overexpression and CRISPR editing.

TERT overexpression is successful across different cell types, including specific blood cells, macrophages, and human kidney cells. (Huang et al., 2024) Each shows a high efficiency in transfection indicating a successful outcome of T-cell immortalization with minimal genomic alteration. Emerging CRISPR editing approaches, including CRISPR-Cas9 genome editing and CRISPRa-mediated transcriptional activation, present a more controlled method of cell immortalization, avoiding insertional mutagenesis and providing controls and potential reversibility. (He et al., 2025; Zhao et al., 2020) Notably, it is the first time that a normal human T cell line is established. However, challenges remain, as the risk of off-target mutation and double strand break induced instabilities could occur. Both techniques demonstrate promising cell immortalization outcomes with TERT overexpression showing minimal genomic instability. CRISPR, as an editing tool, shows positive direction on the mobility of immortalization methods but its amount of negative effects on genomic stability remains unclear.

This review compares TERT overexpression and CRISPR-based immortalization with emphasis on genomic stability, an aspect typically discussed separately in existing studies. By synthesizing findings, this paper evaluates which approach currently offers the most balance between immortalization and genomic stability.