Parece que poderá ser possível em algo que se chamará bacterioterapia:
http://m.nzherald.co.nz/lifestyle/news/article.cfm?c_id=6&objectid=11803567
Citando:
"A genetically-altered form of salmonella has been developed that will attack tumour cells but leave healthy cells alone.
The bugs are a leading cause of food poisoning in the UK each year, reports DailyMail.
It is the latest example of developments in a new field of cancer treatment called "bacteriotherapy".
Experiments on mice using a modified version of salmonella reduced the size of cancer tumours, the American Association for the Advancement of Science annual meeting in Boston heard.
Alterations made to the salmonella bug stopped it attacking and infiltrating into normal healthy cells. Instead it targeted cancer cells."