A major limitation for the use of Ad vectors in gene therapy trials is the development of strong innate and adaptive immune responses against the Ad capsid. Gene therapy can wipe out defective genes, putting an end to all types of genetic disease. Gene therapy doesn’t have to just apply to humans. Scientists have yet to understand fully how the human genes work. Some cancers are caused by more than one gene and some vectors, if used incorrectly, can actually cause cancer or other diseases. 4. Gene therapy is still incomplete, requiring a lot of trials and risks in order to find the correct solution. It could apply to plants as well, eliminating diseases that can devastate entire crops some seasons. The challenges associated with interpreting information from large-scale gene expression experiments in vivo is also discussed. Gene therapies can also apply to animals, which could then help to stabilize the food chain and save producers money as therapies become less expensive. 5. The biology of human gene therapy is very complex, and there are many techniques that still need to be developed and diseases that need to be understood more fully before gene therapy can be used appropriately. Gene therapy, when successful, can have a number of advantages in comparison to drug therapy .For example, this therapy can provide a cure rather than ease the patient's symptoms. Adenovirus–host interactions with circulating blood components and cellular factors restrict Ad5-mediated gene transfer efficiency and the length of the transgene expression, and affect biodistribution of the vectors. Up to this day, researchers are still studying how and when to make use of gene therapy. This technique remains taboo among health experts because the treatment remains under testing. The Disadvantages of Gene Therapy: Needs More Clinical Tests. Gene therapy is a complicated field of research and many questions remain to be answered. In addition, because gene therapy involves making changes to the body’s genetic setup, it raises many unique ethical concerns. It could be used to enhance a person’s overall health. The substitution of defective genes for functional copies also raises ethical questions that must be addressed before accepting these treatments to prevent cancer . This paper addresses some of the limitations and uncertainties of gene expression profiling in mechanistic and predictive toxicology with respect to the expectations of toxicogenomics. As mentioned above, gene therapy remains at the experimental stage. Gene therapy as the process of transplanting genes has developed normally in place of genes that may be missing or have emerged abnormally to correct a genetic disorder. It is a technique that is still in its experimental periods, and so involves some advantages and disadvantages. Gene therapy has shown some promise in treating a large list of diseases such as cancer, cystic fibrosis, heart disease, diabetes, hemophilia and AIDS. Health …