Compared with the benchmarks AAV9 and AAV6, AAV5 shows higher and more homogeneous gene transfer in the left ventricular, and less extra-cardiac vector organ accumulation, without any signs of clinical toxicity in the clinically relevant model., This paper focuses on the application of AAV in gene therapy, and expounds the reasons, mechanism of action, safety issues, strategies to improve treatment efficiency, and specific application examples., Adeno-associated virus (AAV) technology is an essential platform for gene therapies, as it has a low immunogenic profile and a diverse tropism for human tissues. However, a growing body of, They have an excellent and well defined safety profile, and can direct long term transgene expression with tropism for specific tissues such as the liver (for serotypes 2, 5 and 8 among, The objective of this article is to demystify AAV vectors, providing some basic background on the vectors, defining safety concerns, outlining strategies to mitigate safety issues, and discussing recent FDA safety meetings regarding AAV gene therapies., Diligent, collaborative studies of both cancer rates and vector DNA will be needed to understand whether cancer risk is altered in our gene therapy recipients by either vector integration or by other factors.