Virus 
Antibiotic inactivation 
Malignant change in marrow. 
Mesna 
Headache 
Joint pain 
Diarrhea 
Marrow Marking 
No additional side effects have been seen in extensive animal studies of the marrow marking 
technique or in any person treated with the marker genes so far. However, despite this 
apparent safety, there are theoretical risks. For example, although the virus containing the 
marker has been strongly disabled and is considered harmless, it is conceivable that changes 
might occur in the cells in which it is placed, which would allow the virus to recover, grow 
and potentially even cause cancer. The inserted marker may also produce a protein which 
can inactivate certain antibiotics. There are alternative antibiotics available which work as 
well, and these would be used instead. 
Confidentiality 
Your/Your child’s case will be treated in complete confidence, unless you specifically agree 
otherwise. 
However, approved people from Government agencies may review the charts. 
Alternative Procedures 
If you do not want to have part of your/your child’s marrow marked, you^our child could 
still have a transplant with an untreated marrow. If you do not want a transplant at all for 
yourself/your child, we could give treatment with different drug combinations or radiation 
therapy. However, there is no evidence that these therapies would provide an incre 2 ised 
chance of controlling the cancer, although the side effects might be less than the drugs used 
in this treatment. Alternatively, you/your child could have no further therapy. 
Recombinant DNA Research, Volume 14 
