Gene therapy for cancer relies upon the delivery of a therapeutic gene
to a target cell population which may comprise either the tumour cell
s themselves or specific host effector cells with anti-tumour activity
. In addition, gene delivery may be targeted directly to the tumour ce
lls in vivo or towards cells explanted from the patient. The precise r
equirements of the delivery system depend upon the specific therapeuti
c strategy being used in each case, however, delivery must be accurate
, efficient and must result in correctly regulated expression of the g
ene in only the desired cell type. Equally important, the delivery sys
tem must be sale for both the patient and the community as a whole. He
re, we summarize the types of gene therapy which have been proposed fo
r the treatment of cancer and review how currently available delivery
systems are suited to each of these individual strategies.