KEY POINTS:
Gene therapy is an experimental treatment that involves introducing genetic material into a person's cells to fight or prevent disease.
Viruses are normally used to insert genes into cells because of their ability to recognise specific cells. In gene therapy, the viruses used are altered to make them safe for humans.
>> Read our series on latest cancer breakthroughs
>> Donate to the Herald Christmas Cancer Appeal
Last September, the US National Cancer Institute announced that two men with advanced melanoma were cleared of their cancers using genetically modified versions of their own immune cells.
Australia's national science agency, the CSIRO, is developing a novel form of gene therapy aimed at bypassing the need for surgery or radiation by delivering a cell-killing drug directly into the tumour.
A common sheep virus is used to deliver a gene for a special drug-activating enzyme into cancerous prostate cells.
Advances like these are opening up the field towards more individualised treatments.
