Zebrafish (Danio rerio) in cancer research: A revolutionary model for drug testing, discovery, and precision medicine

 Corresponding author: Rutuja Kamble Copyright © 2025 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution License 4.0. Zebrafish (Danio rerio) in cancer research: A revolutionary model for drug testing, discovery, and precision medicine Rutuja Kamble 1, * and Krishnan Karthickeyan 2 1 Assistant Professor, Department of Pharmaceutical Chemistry, SCES’s Indira College of Pharmacy, Tathawade, Pune 411033. 2 Professor and Head, Department of Pharmacy Practice, School of Pharmaceutical Sciences, Vels Institute of Science, Technology and Advanced Studies (VISTAS), Pallavaram, Chennai, Tamil Nadu. World Journal of Biology Pharmacy and Health Sciences, 2025, 24(02), 329-342 Publication history: Received on 01 October 2025; revised on 08 November 2025; accepted on 10 November 2025 Article DOI: https://doi.org/10.30574/wjbphs.2025.24.2.0972 Abstract As a useful model in cancer research, zebrafish (Danio rerio) have made substantial contributions to precision medicine, drug testing, and discovery. They are the perfect system for in vivo research of cancer progression and therapy responses because of their fast growth, genetic resemblance to humans, and transparent embryos. This article examines the use of zebrafish in pharmacogenomics, personalised medicine development, and high-throughput cancer medication screening. We also go over the benefits and drawbacks of using zebrafish models in oncological research as well as its possible applications in precision medicine in the future. Keywords: Zebrafish Model; Cancer Research; Drug Discovery; Precision Medicine; Pharmacogenomics 1. Introduction Since cancer is still one of the world's top causes of death, new methods to personalised medicine and drug development are required. Zebrafish have become well-known because of their conserved genes linked to cancer, capacity to grow tumours that resemble human cancers, and appropriateness for high-throughput drug screening. Their use in cancer has been further enhanced by the creation of xenografts and transgenic zebrafish models [1]. Zebrafish-based drug discovery has made it possible to quickly and affordably identify new cancer treatments by using their transparent embryos to track the development of tumours in real time [2]. Additionally, zebrafish patient-derived xenografts (PDX) are a promising personalised medicine tool that enhances therapeutic decision-making and enables real-time medication response monitoring [3]. Recent studies have shown that zebrafish may be used to mimic some malignancies, including ovarian and breast cancer, and that zebrafish avatars can be used as a translational platform to evaluate targeted treatments [4]. Furthermore, zebrafish models have been essential to the study of lung cancer, helping to improve therapeutic treatments and drug screening [5]. Because of these benefits, zebrafish are becoming more and more popular as a crucial tool in precision oncology, helping to improve our knowledge of tumour biology and build patient-specific treatment plans [6]. The most recent advancements in precision medicine, drug discovery, and zebrafish-based cancer medication testing will be examined in this review, along with their implications for oncological research in the future. Zebrafish have been widely World Journal of Biology Pharmacy and Health Sciences, 2025, 24(02), 329-342 330 recognized as an essential model for studying human diseases due to their genetic similarity to humans and suitability for high-throughput screening. [7] 1.1. Zebrafish in Cancer Drug Testing Because of their fast growth, genetic resemblance to humans, and aptitude for high-throughput screening, zebrafish models have become a useful platform for evaluating cancer drugs. These qualities have made it possible for researchers to carry out comprehensive drug testing and therapeutic compound assessment in a timely and economical way [8]. 2. Why Zebrafish are Effective in Cancer Drug Testing Because of their physiological and genetic resemblance to humans and their capacity for extensive, economical research, zebrafish (Danio rerio) have grown in importance in the testing of cancer drugs [89]. Zebrafish are a great model for researching the pathophysiology of cancer since their genomes are almost 70% similar to those of humans, and they contain orthologs for over 84% of the genes linked to human diseases [10]. For cancer medication screening, their transparency in the early phases of development enables real-time visualisation of tumour growth, angiogenesis, and metastasis [5]. 2.1. High-throughput Screening To find anti-cancer drugs, chemical libraries may be quickly screened using zebrafish embryos. Their optical transparency and tiny size allow for real-time tracking of tumour growth and treatment response. Zebrafish were investigated as drug discovery tools by Macrae and Peterson (2015), who focused on their use in phenotype-based screening [8]. The capacity of zebrafish models to simulate genetic and epigenetic changes in cancer was emphasised by Hason and Bartůněk (2019) [9]. While Kirchberger et al. (2017) [11] showed how zebrafish supplement traditional mouse models, Astone et al. (2017) [6] investigated zebrafish xenografts to evaluate precision cancer medications. Zebrafish xenotransplantation was employed by Bentley et al. (2015) [12] to assess leukaemia treatments. Zebrafishbased quantitative and systems pharmacology was created by Tanaka et al. (2018) [1] for high-throughput in vivo screening. [1] • Dockins et al. (2019) developed standardised procedures for drug testing for leukaemia and breast cancer by optimising human cancer cell xenografts in zebrafish larvae for high-throughput drug screening. [13] • To find anti-metastatic medications, Nakayama and Makinoshima (2020) examined screening models based on zebrafish [14]. • Gallardo et al. (2015) found new chemicals influencing zebrafish cell migration using phenotype-driven chemical screening. [15] • Schmitz et al. (2019) investigated high-throughput drug response screening using zebrafish xenograft breast cancer models. [16] • Mauro et al. (2019) used zebrafish to create automated procedures for the identification of angiogenesis inhibitors. [17] Table 1 High-throughput Screening in Zebrafish Year Key Findings Reference 2015 Explored zebrafish as tools for drug discovery, emphasizing their role in phenotype-based screening. [8] 2015 Used zebrafish xenotransplantation to evaluate leukemia therapies. [12] 2015 Used phenotype-driven chemical screening to discover novel compounds affecting cell migration in zebrafish. [15] 2017 Studied zebrafish xenografts to test precision oncology drugs. [6] 2017 Demonstrated how zebrafish complement classic mouse models in cancer drug screening. [11] 2018 Developed zebrafish-based quantitative and systems pharmacology for high-throughput in vivo screening. [1] 2019 Optimized human cancer cell xenografts in zebrafish larvae for high-throughput drug screening, establishing standardized protocols for leukemia and breast cancer drug testing. [13] World Journal of Biology Pharmacy and Health Sciences, 2025, 24(02), 329-342 331 2019 Developed automated protocols for angiogenesis inhibitor discovery using zebrafish. [17] 2019 Explored zebrafish xenograft breast cancer models for high-throughput drug response screening. [16] 2019 Highlighted zebrafish models' ability to model genetic and epigenetic alterations in cancer. [9] 2020 Reviewed zebrafish-based screening models for identifying anti-metastatic drugs. [14] 2023 Studied zebrafish for lung cancer research. [5] 2.2. In Vivo Drug Efficacy Testing To evaluate the efficacy of new treatment medicines, zebrafish tumour models offer a physiologically appropriate setting. In vivo zebrafish models take into consideration tumor-microenvironment interactions, which are important in the development of cancer, in contrast to in vitro tests [18]. Zebrafish have shown promise in screening and verifying anti-cancer medications in a number of studies Table 2 Key Developments in Zebrafish-Based Oncology Models Year Key Findings Reference 2015 Reviewed the translational potential of zebrafish in oncology, demonstrating their role in screening and validating anti-cancer drugs. [18] 2018 Utilized zebrafish models for pancreatic cancer drug testing. [1] 2019 Introduced a PCR-based zebrafish model to rapidly test drug efficacy in head and neck cancer. [19] 2019 Reviewed zebrafish as a biomedical model, highlighting its role in metabolic disorders and oncology. [20] 2020 Discussed zebrafish avatars as a key tool in precision medicine, enabling patient-specific treatment testing. [3] 2021 Demonstrated the efficacy of zebrafish models in breast cancer therapy development. [2] 2023 Studied zebrafish for lung cancer research, highlighting their utility in drug testing and target validation. [5] 2023 Analyzed zebrafish avatars as a translational platform for predicting patient outcomes in oncology. [21] 2024 Evaluated zebrafish tumor xenograft models for cancer drug development and high-throughput screening of long non-coding RNAs (lncRNAs). [22] 2024 Developed an in vivo drug screening protocol in zebrafish to identify anti-metastatic drugs. [23] Figure 1 Advancements in Zebrafish Models for Cancer Research World Journal of Biology Pharmacy and Health Sciences, 2025, 24(02), 329-342 332 2.3. Toxicity Profiling Zebrafish lessen the need for mammalian models by facilitating the study of medication toxicity at an early stage. Before moving on to mammalian models, the capacity to detect and measure developmental defects, organ toxicity, and systemic side effects in zebrafish eggs offers a reliable platform for evaluating medication safety. [8] Zebrafish offer a predictive model for evaluating drug-induced toxicity, as shown by McGrath and Li (2008) [24], who also pointed out that the toxicity profiles of zebrafish and mammals are comparable. Their research confirmed that zebrafish are a trustworthy substitute for conventional mouse models in preclinical medication development. This was further supported by He et al. (2014) [25], who demonstrated that zebrafish are very predictive of mammalian reactions to hazardous chemicals, especially in evaluations of developmental and reproductive toxicity. ZeGlobalTox is a novel screening method created by Cornet et al. (2017) [26] that enables scientists to evaluate druginduced organ toxicity in zebrafish. Zebrafish are a complete tool for multi-organ toxicity testing since their study included important toxicity endpoints such as cardiotoxicity, neurotoxicity, and hepatotoxicity. In their evaluation of zebrafish as a high-throughput nanotoxicity screening model, Jia et al. (2019) [27] showed how different nanomaterials affect biological systems at varying doses. Zebrafish were highlighted in this study as a useful model for assessing the security of new nanotechnologies. Applications of zebrafish in preclinical toxicity testing, such as evaluating hepatotoxicity, nephrotoxicity, cardiotoxicity, and teratogenicity, were compiled by Miyawaki (2020) [28]. In a similar vein, Cassar et al. (2020) [29] emphasised zebrafish as a link between in vitro tests and investigations on mammals, showing enhanced prediction for toxicities caused by drugs. According to their findings, zebrafish are a model that can improve translational research while lowering the moral dilemmas associated with testing on mammals. Zebrafish-based toxicity tests for paediatric cancer medications were examined in recent research by Azzam et al. (2024) [30], which assessed their contribution to guaranteeing drug safety for younger patients. By creating a zebrafishbased high-throughput screening technique for discovering anti-metastatic medications while reducing systemic toxicity, Nakayama et al. (2024) [23] made significant progress in the field. Together, these results demonstrate the benefits of using zebrafish for medication toxicity testing. They are a vital tool in preclinical drug development and safety pharmacology because of their capacity to anticipate adverse drug responses, offer early-stage toxicity evaluations, and supplement mammalian models. Table 3 Summary of Key Studies in Zebrafish-Based Toxicity Profiling Year Key Findings Reference 2008 Demonstrated zebrafish as a predictive model for assessing drug-induced toxicity, highlighting similarities between mammalian and zebrafish toxicity profiles. [24] 2014 Showed zebrafish as a highly predictive model for mammalian responses to toxic substances in developmental and reproductive toxicity assessments. [25] 2017 Developed ZeGlobalTox, an innovative approach to assessing drug-induced organ toxicity in zebrafish, covering cardio-, neuro-, and hepatotoxicity. [26] 2019 Reviewed zebrafish as a high-throughput nanotoxicity screening model, evaluating the in vivo toxicological profiles of various nanomaterials. [27] 2020 Summarized applications of zebrafish in preclinical toxicity testing, including hepatotoxicity, nephrotoxicity, cardiotoxicity, and teratogenicity assessments. [28] 2020 Highlighted zebrafish as a bridge between in vitro assays and mammalian studies, improving the predictability of drug-induced toxicities. [29] 2024 Investigated zebrafish-based toxicology assays for pediatric cancer drugs, evaluating their role in drug safety assessments. [30] 2024 Developed a zebrafish-based high-throughput screening method for identifying anti-metastatic drugs while minimizing systemic toxicity. [23] World Journal of Biology Pharmacy and Health Sciences, 2025, 24(02), 329-342 333 2.4. Personalized Drug Testing Zebrafish patient-derived xenografts (PDX) provide a potential personalised treatment strategy. Researchers may quickly assess the effectiveness of particular chemotherapy medicines by implanting tumour cells from individual patients into zebrafish eggs. This allows them to customise treatment plans for improved clinical results (Fieuws et al., 2024). [4] Zebrafish avatars have been shown to be useful in functional precision medicine by Fieuws et al. (2024) [4], allowing for real-time evaluation of tumour response to treatments. Zebrafish models were employed by Fazio et al. (2020) [3] to forecast medication reactions for individual patients, opening the door to customised treatment plans. [3]Zebrafish were used for lung cancer screening by Wu et al. (2023) [5], demonstrating their function in evaluating medication responses in various lung cancer subtypes. [5] Macrae and Peterson (2015) evaluated the effectiveness of zebrafish in pharmacogenomics, highlighting their capacity to detect medication reactions unique to each patient. [8]. In their investigation of their function in pancreatic cancer therapy, Tanaka et al. (2018) [1] showed that zebrafish PDX models might be employed for quick drug screening and treatment assessment [1]. Zebrafish applications in leukaemia therapy were examined by Astone et al. (2017) [6], who demonstrated how leukaemia xenografts in zebrafish enable customised drug testing [(Astone et al., 2017)]. [6] Zebrafish PDX models were created by Wang et al. (2022) [31] for the treatment of non-small cell lung cancer, emphasising their application in the screening of immunotherapies and targeted treatments [31].The use of zebrafish patient-derived avatars for intestinal cancer screening was reported by Costa et al. (2022) [32], who also showed how effective these avatars are at evaluating various treatment approaches. [32] Zebrafish leukaemia xenografts were effectively employed by Somasagara et al. (2021) [33] to assess new leukaemia therapy. Together, these results demonstrate the increasing value of zebrafish as a model for customised drug testing, offering an affordable, scalable, and patient-specific platform for assessing cancer treatments. Table 4 Summary of Key Studies in Zebrafish-Based Personalized Drug Testing Year Study Key Findings Reference 2015 Macrae and Peterson Examined zebrafish efficiency in pharmacogenomics and personalized drug screening. [8] 2017 Astone et al. Studied zebrafish applications in leukemia treatment, demonstrating personalized drug testing. [6] 2018 Tanaka et al. Explored zebrafish PDX models in pancreatic cancer therapy for rapid treatment evaluation. [1] 2020 Fazio et al. Used zebrafish models to predict patient-specific drug responses. [3] 2021 Somasagara et al. Applied zebrafish leukemia xenografts to evaluate novel leukemia therapies. [33] 2022 Wang et al. Developed zebrafish PDX models for non-small cell lung cancer treatment. [31] 2022 Costa et al. Utilized zebrafish patient-derived avatars for digestive cancer therapy screening. [32] 2023 Wu et al. Applied zebrafish PDX models for lung cancer screening and drug testing. [5] 2024 Fieuws et al. Demonstrated zebrafish avatars in functional precision medicine for rapid drug assessment. [4] 2.5. Advancements in Zebrafish Research 2.5.1. CRISPR Genome Editing By enabling precise gene alterations to generate disease models and investigate carcinogenesis, CRISPR/Cas9 technology has completely transformed the study of zebrafish cancer. [34] Researchers have been able to explore new treatment targets in zebrafish, create mutations specific to cancer, and eliminate tumour suppressor genes thanks to this genome-editing technology. World Journal of Biology Pharmacy and Health Sciences, 2025, 24(02), 329-342 334 In order to increase accuracy and enable targeted gene alterations in zebrafish cancer models, Liu et al. (2019) extended the CRISPR toolset [35]. Cas12a-mediated gene editing in zebrafish dramatically decreased off-target effects, increasing the precision of cancer model development, as shown by Ouyang et al. (2020).[36] The translational uses of CRISPR/Cas9 for zebrafish gene editing were reviewed by Sharma et al. (2021), indicating its promise for both basic research and therapeutic discoveries [37]. In order to replicate different human diseases, Chaudhary et al. (2020) investigated the use of CRISPR in creating transgenic zebrafish lines [38]. In ground-breaking research, Ablain et al. (2018) highlighted the utility of zebrafish in functional genomics by identifying PVRL1 as a metastasis suppressor gene in melanoma using a tissue-specific CRISPR strategy [39]. These results highlight how CRISPR/Cas9 technology has revolutionised zebrafish cancer research and is an essential tool for medication development and precision oncology. 2.6. AI-Driven Drug Screening Because AI speeds up data processing and predictive modelling for cancer treatments, it has greatly improved zebrafishbased drug development. Nguyen et al. (2021) demonstrated the effectiveness of AI in discovering possible therapeutic compounds by streamlining high-throughput drug screening for breast cancer using AI-powered optical imaging methods in zebrafish xenografts. [40] Grandhi et al. (2021) used AI-driven 3D tumour enrichment tests in zebrafish, which enabled high-throughput real-time monitoring of treatment resistance mutations [41]. Haney et al. (2020) improved the standardisation of engrafted tumour area estimation by automating zebrafish drug screening through the use of AI-assisted fluorescence imaging. [42] The development of tailored therapies is advanced by AI-based chemical screening techniques that use zebrafish models to quickly identify tiny compounds that inhibit cancer, as noted by Xie et al. (2015) [43].AI-driven phenotyping of zebrafish embryos was proven by Terriente and Pujades (2013), which made it easier to identify anti-cancer drugs through high-throughput screening [44]. An AI-assisted pipeline was shown by Dockins et al. (2019) to standardise zebrafish xenograft procedures for drug testing, improving tumour cell injection and response assessment [13]. Bozhko et al. (2021) showed the potential of AI in pharmacological screens outside of cancer by using AI neural network algorithms to categorise zebrafish behavioural responses to psychoactive substances [45]. 2.6.1. 3D Imaging and Optical Screening Real-time visualisation of tumour growth and medication responses is now possible thanks to recent advancements in 3D imaging technology, revolutionising zebrafish-based cancer research. For the study of zebrafish models, optical projection tomography (OPT) has become a potent 3D imaging method. High-resolution reconstruction of both live and preserved zebrafish specimens is possible with zOPT, an open-source OPT platform designed for zebrafish imaging and created by Zhang et al. (2020) [46]. Nguyen et al. (2021) investigated optical imaging methods in zebrafish xenografts to provide high-throughput drug screening for breast cancer, proving that autofluorescence lifetime imaging could predict treatment response. [40] To allow single-cell resolution imaging of cancer cell heterogeneity, tumour development, and microenvironment interactions, Tang et al. (2016) used optically transparent, immune-compromised zebrafish [47].Yan et al. (2020) [48] demonstrated the preclinical effectiveness of several chemotherapy combinations by introducing high-resolution dynamic single-cell imaging of human cancer development and treatment responses after engraftment into immunodeficient zebrafish. [47] Jones matrix optical coherence tomography (JM-OCT) was created by Lichtenegger et al. (2022) to non-destructively assess tumour anomalies in zebrafish models, emphasising its use in preclinical research [49]. In order to provide quantitative optical tomography for cancer progression and vascular development in vivo, Kumar et al. (2016) improved 3D fluorescent imaging in zebrafish [50]. World Journal of Biology Pharmacy and Health Sciences, 2025, 24(02), 329-342 335 The efficiency, accuracy, and scalability of zebrafish-based cancer research have been greatly enhanced by these developments in CRISPR genome editing, AI-driven drug screening, and 3D imaging, making them a crucial tool in oncology drug discovery. Table 5 Summary of Key Technological Advancements in Zebrafish Cancer Research Technology Key Findings Reference CRISPR Genome Editing Enhanced precision in gene modifications for cancer modeling in zebrafish. [34] CRISPR Expansion Improved targeted gene modifications for disease modeling. [35] AI-Driven Drug Screening AI-powered optical imaging enhances high-throughput screening. [40] 3D Tumor Enrichment Assays AI-driven 3D tumor screening identifies drug resistance mutations. [41] Live-Cell Imaging Used zebrafish for melanoma and squamous cell carcinoma studies. [51] High-Throughput Imaging Applied in cardiovascular and cancer research. [52] Optical Projection Tomography (OPT) zOPT platform enables high-resolution reconstruction of zebrafish specimens. [46] Autofluorescence Lifetime Imaging Predicts drug response in zebrafish xenografts for breast cancer screening. [40] Immune-Compromised Zebrafish Imaging Enables single-cell resolution imaging of tumor heterogeneity and evolution. [47] Dynamic Single-Cell Imaging Captures real-time growth and therapy response in zebrafish cancer models. [48] Jones Matrix Optical Coherence Tomography (JM-OCT) Non-destructive tumor characterization in zebrafish models. [49] 3D Fluorescence Imaging Enables quantitative optical tomography of cancer progression. [50] 2.7. Advantages Over Traditional Models 2.7.1. Cost-Effectiveness An affordable substitute for mammalian models like mice and rats is zebrafish. Because of their compact size, researchers can shelter vast populations in a little amount of area, which drastically lowers facility expenses. Largescale investigations are also more cost-effective since zebrafish may be kept in high-density aquatic habitats and require less feed.[53] 2.7.2. Rapid Reproduction and Development In contrast to mice, which take around 20 days to mature, zebrafish embryos grow externally and finish organogenesis 24 to 48 hours after fertilisation. This quick development speeds up the drug discovery process and allows for quicker experimentation.[54] 2.7.3. Genetic Similarity to Humans Nearly 84% of the genes linked to human diseases have a zebrafish equivalent, and humans and zebrafish share about 70% of their genes [55]. They are a great model for researching cancer and evaluating targeted treatments because of their genetic similarities. 2.7.4. Transparency for Imaging Real-time, non-invasive visualisation of tumour growth, medication responses, and metastasis is made possible by the optical transparency of zebrafish embryos and larvae. High-resolution imaging methods, which are challenging to accomplish in murine models, can be utilised to follow the growth of tumours using fluorescent markers [56]. World Journal of Biology Pharmacy and Health Sciences, 2025, 24(02), 329-342 336 Figure 2 Comparison between Traditional Models vs Modern Models.Modern Models offer cost-effective, rapid and transparent advantages Future Directions • AI and Machine Learning in Drug Screening Oncology research is on the brink of a significant revolution, thanks to the integration of artificial intelligence (AI) and machine learning (ML) in zebrafish-based medication screening. By harnessing the power of AI, researchers can utilize advanced picture analysis techniques to swiftly determine how a tumor responds to various medications, eliminating the need for time-consuming human review processes. Moreover, machine learning algorithms have been meticulously trained to analyze and interpret hundreds of zebrafish tumor images, enhancing the efficiency and accuracy of the screening process [40]. This innovative approach holds immense promise for enhancing the effectiveness of oncology research and ultimately improving patient outcomes. • Personalized Medicine Applications By introducing patient-derived tumour cells into zebrafish embryos, zebrafish xenografts are becoming more potent instruments for personalised treatment. Oncologists may utilise these models to quickly evaluate a variety of medication combinations, assisting them in customising patient care. Zebrafish xenografts have been demonstrated in recent research to reliably predict clinical outcomes in patients with breast and colorectal cancer.[57] • CRISPR-Based Cancer Models Zebrafish models are increasingly being used to create precise cancer mutations using the CRISPR-Cas9 gene-editing technique. By studying tumour development and progression in real time, these gene-edited animals enable researchers to develop more precisely targeted treatments. It is anticipated that sophisticated CRISPR methods like base editing and prime editing would increase the accuracy of zebrafish cancer models.[58] World Journal of Biology Pharmacy and Health Sciences, 2025, 24(02), 329-342 337 • Integration with Humanized Models In order to create "humanised" zebrafish models, human immune cells, tumour microenvironments, and vasculature are being included. These developments will close the gap between preclinical testing and human trials and improve the therapeutic relevance of zebrafish cancer investigations.[48] 3. Comparison of Zebrafish, Mice, and Organoid Models in Cancer Research Model species and systems that closely mimic human tumour biology, treatment response, and disease progression are used in cancer research. A number of variables, including genetic similarities, tumour microenvironment, drug screening effectiveness, and ethical issues, influence the choice of model, whether it be zebrafish, mice, or organoids. Zebrafish and organoids are becoming strong substitutes with distinct benefits, while mouse models have long been the gold standard. 3.1. Zebrafish (Danio rerio) as a Cancer Model Because of their approximately 70% genetic closeness to humans and their capacity to form tumours that mimic human cancers, zebrafish have gained popularity as oncology models [9]. Real-time monitoring of tumour development, angiogenesis, and metastasis is made possible by their optically transparent embryos [5]. Because thousands of embryos may be treated at once, zebrafish are also perfect for high-throughput drug screening, which drastically cuts down on time and expense [8]. However, the translational potential of zebrafish models may be limited due to their absence of some essential human physiological characteristics, such as lungs and a fully functional adaptive immune system [10]. In spite of this, zebrafish patient-derived xenografts (PDX) are transforming personalised medicine by allowing quick testing of chemotherapeutic medications on tumours specific to each patient [4]. 3.2. Mice Models in Cancer Research Because of their well-established tumour engraftment techniques, fully developed immune systems, and great genetic resemblance to humans (~85%), mice have been the gold standard in cancer research [59]. In order to comprehend the course of cancer, scientists can investigate certain oncogenes and tumour suppressors using genetically modified mouse models (GEMMs) [46]. Prior to clinical trials, mouse xenograft models (PDX and CDX) provide an in vivo platform for evaluating new cancer medications [60]. • Mice models have drawbacks despite their benefits: • Expensive and lengthy experimental schedules • Disparities in human physiology and metabolism that might result in variations in medication metabolism [61]. They are less effective than zebrafish for early-stage drug screening because to their limited high-throughput applications.[11] 3.3. Organoid Models in Cancer Research Organoids are three-dimensional (3D) cell cultures made from patient tumours that retain the original cancer's genetic and epigenetic features [62]. These models are perfect for drug response testing and personalised treatment because they closely resemble the biology of human tumours [63]. They have been effectively used to lung, breast, and colorectal malignancies, allowing for patient-specific medication screening [31] However, the absence of essential elements of the tumour microenvironment, including stromal connections, immune cells, and blood arteries, limits the capacity of organoids to simulate immune response and metastasis [64]. Drug penetration issues and culture variability continue to be obstacles in the development of co-culture systems with immune cells [65].