Gene therapy involves the transfer of nucleic acids to somatic cells for the treatment of genetic disorders in humans. In this therapy, disease-causing genes are removed or replaced with normal or functional genes to fulfill the enzyme or protein requirement of the body. The disease is expected to be eliminated after gene therapy.

The idea of gene therapy was introduced by Joshua Lederberg in 1963; however, research on human genetics did not accelerate until the 1980s. Subsequently, the first clinical study on gene transfer was conducted by Anderson et al. in 1990. In that study, a 4-year-old girl with adenosine deaminase (ADA) deficiency was treated by transfecting the ADA gene into her white blood cells, resulting in considerable improvements in her immune system. In the same year, gene therapy was also tested on patients suffering from melanoma, and the results showed that retroviral gene transfer was safe and practical. Since 1989, more than 900 clinical trials on gene therapy have been approved worldwide. Among these trials, 70% are in the area of cancer gene therapy. To date, substantive progress has been made in gene therapy, and this progress has benefited from advancements in the therapeutic strategies discussed next.

Gene Delivery Systems

Although considerable strides have been made in developing gene-based therapeutic strategies, establishing efficient and safe gene delivery systems remains the main challenge in tumor gene therapy. The gene therapy vectors used in gene delivery systems can be categorized into two groups: viral and non-viral systems.

Viral systems

Viral vectors, which can transfer genetic materials into host cells, are biological systems derived from naturally evolved viruses. Viruses used in gene therapy have been modified to increase safety, enhance specific uptake, and improve efficiency. The viral vectors include retrovirus, adenovirus, Herpes simplex virus (HSV), adeno-associated virus (AAV), and poxvirus (vaccina virus). The most commonly used DNA viral vectors are based on adenoviruses and AAVs. The understanding of viral vectors has increased greatly and their design and production have been improved. Several clinical trials have been performed for various viral vectors. However, there are some drawbacks in terms of the safety and toxicity of these vectors and the size of the transfected genetic material. Therefore, great caution should be exercised when using viral vectors for the treatment of human diseases, and this topic should be investigated further.

Non-viral systems

The limitations associated with viral vectors have encouraged researchers to focus on non-viral systems. Many methods have been developed for the non-virus-mediated delivery of genetic materials, including non-viral vectors and physical approaches.

Non-viral vectors

Non-viral vectors are safe, can be constructed and modified by simple methods, and exhibit high gene encapsulation ability. Non-viral vectors include Cationic polymers like polyethylenimine (PEI) and poly-L-lysine (PLL), Cationic peptides, and Cationic liposomes. Among these vectors, liposome is widely used in clinical trials for tumor therapy. In HLA-B7-negative melanoma patients, antitumor immunity is induced by injecting Cationic liposomes containing HLA-B7- and β-2 microglobulin–encoding genes. Further, patients with glioblastoma have been treated with Cationic liposomes containing the β-interferon– encoding gene. Hence, liposomes are considered safe for use in humans.

Shell nanoparticles, the newly described Cationic core, offer more advantages than liposomes, namely, high gene transfection efficiency and concurrent delivery of drugs and genes to the same cells . Another advantage of nanoparticle-based therapeutic strategies is that they simultaneously have enhanced efficacy and reduced adverse effects. This advantage can be attributed to properties such as their passive and active targeting. Passive targeting allows effective localization of targets in tumor cells based on “enhanced permeability and retention (EPR)”. Coating nanoparticles with targeting molecules, such as antibodies, peptides, nucleic acid aptamers, carbohydrates, and small molecules, can enhance the cellular uptake of nanoparticles. For example, using a Wistar rat model which had implanted with folate receptor-expressing C6 glioma cells, significant growth inhibition of C6 glioma xenografts was observed after treatment with nanoparticle/targeting molecule combinations, FA-PEG-PEI/pCD/5-FC and FA-PEG-PEI/pTRAIL  Unlike other types of therapeutic agents, nanoparticles allow for custom design and property-tuning. Further, as more clinical data becomes available and the optimal therapeutic properties of nanoparticles becomes clear, the nanoparticle-based approach will continue to improve.

In this Research Topic collection we invite researchers to submit manuscripts along the following themes:

Manuscript contributions that deal with Cancer, Recent advances in vaccines for cancer, Medication, etc.

- Interdisciplinary research, observational field studies, experiments or manipulations, meta-analyses, reviews or modelling approaches are also welcome.

Journal of Cancer Diagnosis is now accepting submissions on this topic. A standard EDITORIAL TRACKING SYSTEM is utilized for manuscript submission, review, editorial processing and tracking which can be securely accessed by the authors, reviewers and editors for monitoring and tracking the article processing. Manuscripts can be uploaded online at Editorial Tracking System https://www.scholarscentral.org/submissions/cancer-diagnosis. or forwarded to the Editorial Office at mailto:manuscripts@omicsonline.com

 Nancy Ella                                           
Journal Manager
Journal of Cancer Diagnosis
Email:mailto:manuscripts@omicsonline.com