The June 19, 2008
headline reads “US doctors kill skin cancer with cloned T-cells.” Does this suggest that human cloning of embryonic
stem cells has been successful in treating skin cancer?
Absolutely not!
The details of the New England
Journal of Medicine report that generated this news coverage reveal that adult stem cells
obtained from the patient were used. As reported in ScienceDaily,
researchers “removed CD4+ T cells, a type of white blood cell, from a
52-year-old man whose Stage 4 melanoma had spread to a groin lymph node and to a lung. T
cells specific to targeting the melanoma were then expanded vastly in the laboratory using
modifications to existing methods.”
The exciting result was an apparent
cure of melanoma for this patient. “Two months later, PET and CT scans
revealed no tumors. The patient remained disease free two years later, when he was last
checked.”
Can other melanoma patients expect to
receive this treatment soon? The reality
check came from researcher Cassian Yee, M.D. “Yee cautioned that these results
represent only one patient with a specific type of immune system whose tumor cells
expressed a specific antigen. More studies
are needed to confirm the effectiveness of the experimental T-cell therapy.”
The widely reported introduction for
this news story was: “US doctors have for the first time successfully treated a skin cancer patient with cells cloned from his own immune system.” The
story included a later reference stating that the treatment “used his own
cloned infection-fighting T-cells.”
How many people will immediately think
of cloned human beings? That has become a
common reference point in the debate over stem cell research since cloning of embryos to
obtain stem cells is considered a necessary step by advocates of embryonic stem cell
research.
Technically, use of
“cloned” in the news report about treating melanoma is accurate. A definition of cloning states, “Cloning is
the process of making an identical copy of something. In biology, it collectively refers
to processes used to create copies of DNA fragments.”
However, since reporting of this
stem cell research success never used the phrase “adult stem cells” even though
the original cells were taken directly from the patient, confusion is very likely to occur
for many readers, whether that confusion was intended or not.
This news represents an exciting
medical breakthrough that will become even more exciting if it can be duplicated by
additional studies. This breakthrough was
achieved using adult stem cells that were isolated based on specific characteristics and
encouraged to duplicate themselves so large numbers of these stem cells could be infused into the patient.
This result again demonstrates that killing embryos (cloned or otherwise) for stem
cells is not required to achieve medical breakthroughs.