Evening star., 1953-10-23
Science Wins q Round
In Fight on Leukemiu
Resistance to Poisons
Among Cells Discovered
By Thomas R. Henry

n 1OL1S 6GCP AI1cdu OUWdTU uI1QGIS
standing-and possibly eventual treat
ment-of 1eukemia. the invariably fatal
cancer Of the blood, has been taken
with the discovery by National Insti-
tuteS Of Health scientists Of the evolu-
tionary phenomenon Of resistance to
poiSonS among leukemic cells.
The findings may eventually be ap-
piled to most other forms of cancer,
although they have not yet reached the
point of any medical application and
have been confined to one type of leu
kemia in mice.
The phenomenon is the same as that
which has arisen with antibioticS-
especially the highly promising strepto-
mycin in treatment of tuberculosis.
For some time it has been known that
striking remiSsionS of acute lymphocetic
anemia, the type common in children
and probably the most tragic of all,
could be brought about by two types Of
drugs. These were the so-called folio
acid goniStS-moSt notably ame-
thopterine and minoptherine-and the
anti-purines, the best known of which
Is mercapto-purine. The ordinary leu
kemic lymph cells apparently require
both the vitamin folio acid and purineS
for their metaboliSm. These drugs pre-
vent them from making use of the SUBJ
stances and they die quickly. They ap-
pear to be much more sensitive to the
drugs than normal body and blood cells,
which have similar metabolic require
mentS.
False Hopes Arise.
Thus for several years tragically false
hopes have been aroused when child
leukemia victims, apparently quite close
to death, have been brought back to
normal health for short periods by one
Of these drugs. Optimistic doctors
sometimes have announced that they
have discovered "leukemia cure" But
the story always has been the same
sudden remission to q worse stage Of
the disease than before, leading rapidly
to death. All that has been accom-
pliShed is slight lengthening of life.
In exceptional cases this may have
been for a year or more.
The reason for this has been deter
mined by DR.. L. w. Law of the National
Cancer Institute in rat experiments
with what apparently is the same kind
of leukemia as that affecting children.
IL
their inherent resistance to the poisons.
Those with low resistance are killed
quickly. The lymph cell count goes
down rapidly and it seems as if cure
has been obtained. The more resistant
cells. however, are left alive and become
the ancestors of a highly resistant
strain. These can take without damage
any amount of the poisons offered
them. Eventually some of them come
to require it, as some tubercle bacilli
come to depend on streptomycin.
In tuberculosis this phenomenon has
been partly overcome by administering
jointly several kinds of drugs, all
poiSonS. Those bacilli which acquire
resistance to streptomycin do not ac-
quire it for some other poison. BY
using two or more jointly it is pos
sible to secure long remissions and
restore the victim to apparent good
health.
Heavy Doses Required.
BY combinations of the anti-metabo-
Htes-substanceS which interfere with
the utilization of necessary materials
by the leukemic cells-Dr. Law has been
able to secure long leukemic remissions
in his experimental mice. Heavy doses
are required, however. The National
Cancer Institute eXperimenters still are
far from anything that they can pro-
pose for treatment of human victims.
They do not know that the phenomenon
will be the same in children as in mice
Or that there would be similar find
lngS for other forms of leukemia such
as are more common in adults.
Still the findings are considered as
potentially among the most significant
yet made at the institute.
The history of all drug treatment Of
cancer for century has been the same.
Every now and then something seems
> to work. malignant growth disap-
pears. The evidence is convincing and it
IS prematurely announced that some
body has found cancer cure" Almost
invariably, however, there have been
remissions. the malignant growth has
come back worse than before, and
death has been hastened, if anything.
DR.. Laws work gives good reason
to believe that this always will be the
case so far as any single drugs are
concerned. 1t is quite likely that all
malignant cells will behave somewhat
like Emphatic leukemia cells. AS a
result of the findings there may be a
change OF emphasis towards treatment
with combinations of drugs, all effective
to some degree, rather than dependence
on eventual discovery of some one drug
which will cure one or more kinds of
cancer.
1t is emphasized. however, that DR..
Laws work applies only to rats and.
up to now. can be considered only as
providing a promising lead rather than
new kind of treatment.