In the last decade the progress in biochemistry, molecular biology, and bacteriology caused a great deal of attention to be paid for the use bacteria in cancer therapy. Some applications in this area are the use of bacteria as sensitising agents for chemotherapy, as vectors for gene therapy and as delivery agents for anticancer drugs.

In this field, especially Escherichia coli genes and enzymes have been the targets for pro-drug approaches to cancer therapy where inert pro-drugs can be converted to highly active species in vivo. Moreover, IL-4 fused with Pseudomonas exotoxin has been applied directly into malignant brain tumours and binds with high affinity to IL-4 receptors not present on normal brain cells an approach by which major part of the tumour is destroyed without harming the normal brain tissue.

This review is focused on the anticancer agents of microorganism origin that are used to treat some cancer types