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Genetics and Human Malleability
85
that is, to mark these cells so that they could be studied in blood and tumor
specimens from the patient over time.
The TIL were marked with a vector (called N2) containing a bacterial
gene that could be easily identified through recombinant DNA techniques.
Our protocol was called, therefore, the N2-TIL Human Gene Transfer
Clinical Protocol. The first patient received gene-marked TIL on May 22,
1989. Five patients have now received marked cells. No side effects or prob
lems have thus far arisen from the gene transfer portion of the therapy. Use
ful data on the fate of the gene-marked TIL are being obtained.
But what was done that was new? Simply, a single gene was inserted into
a population of cells that had been obtained from a patient’s body. There
are an estimated 100,000 genes in every human cell. Therefore the actual
addition of material was extremely minute, nothing to correspond to the
fears expressed by some that human beings would be “re-engineered.”
Nonetheless, a functioning piece of genetic material was successfully
inserted into human cells and the gene-engineered cells did survive in
human patients.
What Will We Be Able to Do?
Although only one clinical protocol is presently being conducted, it is
clear that there are several applications for gene transfer that probably will
be carried out over the next five to ten years. Many genetic diseases that are
caused by a defect in a single gene should be treatable, such as ADA defi
ciency (a severe immune deficiency disease of children), sickle cell anemia,
hemophilia, and Gaucher disease. Some types of cancer, viral diseases such
as AIDS, and some forms of cardiovascular disease are targets for treatment
by gene therapy. In addition, germline gene therapy, that is, the insertion of
a gene into the reproductive cells of a patient, will probably be technically
possible in the foreseeable future. My position on the ethics of germline gene
therapy is published elsewhere.5
But successful somatic cell gene therapy also opens the door for enhance
ment genetic engineering, that is, for supplying a specific characteristic that
individuals might want for themselves (somatic cell engineering) or their
children (germline engineering) which would not involve the treatment of a
disease The most obvious example at the moment would be the insertion of
a growth hormone gene into a normal child in the hope that this would make
the child grow larger. Should parents be allowed to choose (if the science
should ever make it possible) whatever useful characteristics they wish for
their children?
5.
W. French Anderson, “I Inman Ciene Therapy: Scientific and Ethical Considerations,
'Journal of Alcdicinc and Philosophy
I0 (1 ()<S5): 275 () 1.