Addressing the challenges of immunogenicity, heterogeneity and tumorigenicity in the clinical translation of human embryonic stem cells

The clinical translation of human embryonic stem cells (hESCs) presents promising potential for regenerative medicine, offering innovative treatments for a diverse array of conditions including neurodegenerative diseases, spinal cord injuries, diabetes, and heart disease. This review article navigates the complex landscape of hESCs application, centering on the challenges of tumorigenicity, immunogenicity, and heterogeneity that impede their clinical translation. Tumorigenicity poses a significant safety concern, necessitating the development of stringent differentiation protocols to prevent the formation of tumors post-transplantation. Immunogenicity, due to the allogeneic nature of hESC therapies, demands innovative solutions such as HLA typing and gene editing techniques to attenuate immune rejection. Heterogeneity among hESC lines hinders standardization and reproducibility, essential for regulatory approval. This review highlights strategies to address challenges in clinical hESC applications, including HLA haplotype banks and cloaking for immune compatibility, the critical role of safety monitoring, as well as key regulatory frameworks and interlaboratory potency standardization to support translation. Meanwhile, the review points to future needs for advanced gene editing for immune modulation, more precise cell differentiation techniques, and robust ethical and regulatory frameworks, plus accumulating human clinical data for key technologies and optimizing long-term safety monitoring to maximize hESCs' therapeutic potential safely and ethically.