Monday, October 29, 2012

Arsenic Cancer Therapy

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. 

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