Gene therapy vectors, tissue-specific

A great number of tissue-specific promoters has been isolated and characterized, and some of these have been used in experimental cancer gene therapy (see Table 1). Obviously, tissue-specific promoters are also active in the normal tissue from which the tumor originated. Unless the loss of these normal cells is acceptable (as in the case of melanocytes), additional specificity mechanisms need to be considered to make the resulting vector useful for a systemic delivery. This can be achieved, for example, by introducing an additional level of specificity, such as a specificity for proliferating cells or a selectivity for other conditions that are characteristic of tumor cells (see later). 

AAV has been considered as a potential vector for gene therapy because of its wide range of tissue specificity, its ability to infect and... 

Viral vectors have been the most commonly used means of gene delivery for both VEGF-A and FGF-2. Gene therapy presents an attractive alternative to purified proteins because it offers the possibility of sustained production of one or more factors following a single administration. Furthermore, tissue-specific and highly localized production of the therapeutic factor is possible, through the use of tissue-specific promoters. 

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