Table 1.

Pros and cons of gene delivery methods.

Method	Pros	Cons
In vivo gene delivery	Straightforward	Difficult to target specific cells or tissues Risk of unwanted biodistribution Less control over efficiency of expression
Ex vivo gene delivery	Better control of targetted cells and expression level	Complex protocols of cell isolation and expansion might lead to a costly product and a difficult regulatory pathway.
Viral vectors	High efficiency of gene delivery	Risk of an immune response Risk of tumorigenicity due to insertional mutagenesis Stable integration might lead to an excess of protein secretion Production might be costly and complex
Non-viral vectors	Considered safer compared to viral vectors. Simpler production process Easier manipulation	Low efficiency of gene delivery