_1748708118 20250531161518000 Rovedar Daryoushbabazadeh@gmail.com Rovedar Journal of Lab Animal Research J Lab Anim. Res 2980-9703 04 29 2025 4 2 Mehran Bahmani https://orcid.org/0009-0009-3478-6658 The CRISPR-Cas9 system has revolutionized genome editing, offering unprecedented precision and efficiency in gene modification. Its potential in cancer therapy, particularly oncolytic gene therapy, has garnered significant attention, especially with the development of advanced delivery platforms. However, effective and safe in vivo delivery of CRISPR components remains a major barrier to clinical translation. This review provides a comprehensive overview of viral and non-viral nanocarrier systems for CRISPR-Cas9 delivery, with a particular focus on their application in xenograft models of cancer. The present study aimed to bridge the gap between molecular innovation and therapeutic application by evaluating the efficiency and safety of CRISPR-Cas9 delivery systems in preclinical oncology models. The mechanisms and classifications of viral vectors, including adeno-associated viruses (AAV), lentivirus, and adenovirus, were emphasized, highlighting their strengths in gene transfer efficiency, while addressing concerns over immunogenicity, genome integration, and scalability. Subsequently, non-viral nanocarriers, including lipid nanoparticles (LNPs), polymeric systems, dendrimers, and metallic nanoparticles, have emerged as safer and more customizable alternatives. Key considerations, including stability, endosomal escape, payload capacity, and tumor targeting, are evaluated, supported by findings from recent xenograft-based studies. A direct comparison between viral and non-viral systems was presented, emphasizing differences in transfection efficiency, biosafety, immunological responses, and gene-editing precision in preclinical tumor models. The clinical relevance of CRISPR-based oncolytic strategies was examined, along with their integration with other cancer therapies. Additionally, the emerging challenges of immune evasion, tumor heterogeneity, and delivery barriers were evaluated. In addition, the regulatory and ethical dimensions surrounding genome editing in cancer therapy are addressed, including long-term safety concerns, germline editing considerations, and global disparities in clinical oversight. The discussion concluded with an examination of future perspectives, highlighting strategic improvements in delivery technologies and validation pipelines. Xenograft models were proposed as a means to accelerate clinical translation. 04 29 2025 12 21 https://creativecommons.org/licenses/by/4.0 10.58803/jlar.v4i2.66 https://jlar.rovedar.com/index.php/JLAR/article/view/66 https://jlar.rovedar.com/index.php/JLAR/article/download/66/104 https://jlar.rovedar.com/index.php/JLAR/article/download/66/104 10.1080/08830185.2019.1677645 10.58803/jlar.v1i1.13 10.1002/anie.201504741 10.1080/17425247.2018.1517746 10.3389/fbioe.2022.973326 10.4103/2277-9175.98152 10.3390/ijms20215491 10.1016/j.jconrel.2022.01.013 10.1016/j.apsb.2021.05.020 10.1038/s41392-023-01419-2 10.1002/jgm.3107 10.1186/s13036-018-0127-2 10.58803/RBES.2023.2.1.02 10.1016/j.omtm.2021.03.018 10.1038/s41417-023-00597-z 10.3390/v11010028 10.3389/fbioe.2022.895713 10.1016/bs.pmbts.2018.05.001 10.1080/17425247.2022.2100342 10.1002/btpr.2484 10.1016/j.cell.2020.03.023 10.1208/s12249-024-02834-6 10.1016/j.jconrel.2021.03.030 10.1002/adma.202300665 10.1016/j.jconrel.2023.08.028 10.1039/D2BM01001A 10.1016/j.addr.2024.115359 10.7150/thno.84291 10.3390/pharmaceutics14122682 10.1021/acs.chemrev.5b00346 10.1016/j.progpolymsci.2009.01.002 10.1021/acs.chemrev.3c00705 10.1002/wnan.1364 10.3390/polym11040745 10.2174/2210681209666190807145229 10.1166/jbn.2016.2122 10.2174/1385272820666161025161853 10.2147/JHC.S456683 10.1016/j.heliyon.2024.e38165 10.2147/IJN.S243155 10.1002/smll.202312153 10.3390/ijms25137333 10.1007/s13346-023-01362-3 10.3390/molecules30040962 10.1007/978-981-13-0481-1_4 10.1016/j.jconrel.2022.01.008 10.1002/adma.202303261 10.1208/s12248-021-00608-7 10.3390/polym13193307 10.3389/fmmed.2022.1054069 10.1016/j.jconrel.2022.01.047 10.1177/10915818231153996 10.1021/acsnano.4c13146 10.3389/fimmu.2024.1444437 10.3390/cells11182781 10.3389/fonc.2020.01387 10.3389/fonc.2022.755053 10.1186/s40164-023-00457-4 10.1016/j.humimm.2018.09.007 10.1186/s13287-021-02510-7 10.1038/cr.2016.142 10.3390/ijms241512317 10.1007/s00262-018-2281-2 10.1089/nat.2019.0790 10.1002/bies.202000047 10.1038/s41467-019-11955-7 10.7150/thno.47007 10.1134/S1068162019060025 10.1016/j.ymeth.2017.04.003 10.1038/s41467-018-05843-9 10.1016/j.xphs.2019.10.003 10.1038/mt.2009.41 10.1002/EXP.20240095 10.3389/fmed.2024.1527600 10.3390/v13050822 10.1038/s41392-023-01407-6 10.1038/s41573-019-0029-0 10.1111/pbi.13383 10.1111/rego.12335 10.1016/j.actbio.2024.04.010 10.1093/bmb/ldx002 10.1073/pnas.2004837117 10.1080/14787210.2024.2360684 10.1016/j.jcyt.2024.02.007