More famous as the poison of choice in murder mysteries due
to its not so obvious symptoms, does arsenic has the potential for a more
useful role in cancer therapy?
By: Ringo Bones
Since ancient times and until Victorian period murder
mysteries, writers and murderers have often resorted to arsenic largely because
its symptoms resemble that cholera. It wasn’t until the advances of analytic
chemistry in the 19th Century that law-enforcement forensic teams
have amassed enough knowledge to tell whether arsenic was used to poison
someone. And given its role as a cure for venereal diseases before the advent
of antibiotics and its recently reprised role as a cure for
antibiotic-resistant venereal diseases does arsenic – or more accurately arsenical
compounds – now have a role in cancer therapy?
In a pilot study during the late 1990s, it was shown that
certain medical arsenic compounds is given in low doses to patients with a rare
form of leukemia known as APL or acute promyelocytic leukemia, nearly all
patients go into remission. The
treatment – using all-trans retinoic acid (ATRA), a derivative of vitamin
A, is mixed with arsenic trioxide – has
back then been found to have fewer side effects than conventional chemotherapy
previously used on APL using only ATRA.
APL or acute promyelocytic leukemia is a subtype of acute
myelogenous leukemia or AML, a cancer of the blood and bone marrow – and it is
also known as acute progranulocytic leukemia. Acute promyelocytic leukemia was
first identified in 1957 and from then until the elucidation of its
developmental mechanism by medical researchers during the 1970s, APL had a 100
per cent mortality rate as there was still no effective treatment. After years
of further study, it was later found out that APL is unique among myeloid types
of leukemia due to its sensitivity to all-trans retinoic acid or ATRA. But it
wasn’t until the chemotherapy regimen consisting of ATRA and arsenic trioxide
that was developed during the late 1990s that APL leukemia was no longer the
death sentence it previously was.