Search for cancer cures in Amazon
The task of harvesting the secrets of Brazil's vast Amazon rain
forest that could help in the battle against cancer largely falls to
Osmar Barbosa Ferreira and a big pair of clippers.
In jungle so dense it all but blocks out the sun, the lithe
46-year-old shimmies up a thin tree helped by a harness, a strap between
his feet, and the expertise gained from a lifetime laboring in the
forest.
A few well-placed snips later, branches cascade to a small band of
researchers and a doctor who faithfully make a long monthly trip to the
Cuieiras river in Amazonas state in the belief that the forest's
staggeringly rich plant life can unlock new treatments for cancer.
They may be right.
About 70 percent of current cancer drugs are either natural products
or derived from natural compounds, and the world's largest rain forest
is a great cauldron of biodiversity that has already produced medicine
for diseases such as malaria.
But finding the right material is no easy task in a forest that can
have up to 400 species of trees and many more plants in a 2.5-acre
(1-hectare) area, and in a country where suspicion of outside
involvement in the Amazon runs strong.
"If we had very clear rules, we could attract scientists from all
over the world," said the doctor, Drauzio Varella, with a mix of
enthusiasm and frustration. "We could transform a big part of the Amazon
into an enormous laboratory."
As it stands, though, foreigners are barred from helping oncologist
Varella and the researchers from Sao Paulo's Paulista University, who
are among a tiny handful of Brazilian groups licensed to study samples
from the Amazon.
Varella, 66, believes his high profile has helped. He is a well-known
writer and television personality who shot to fame in 1999 with a book
and subsequent hit movie based on his work as a doctor in a brutal Sao
Paulo prison called Carandiru.
But a move by his team in the 1990s to partner with the U.S. National
Cancer Institute produced a storm of accusations of "bio-piracy" and for
years it has been blocked from the international cooperation and funding
that could increase the chances of finding the Holy Grail of a cancer
cure.
Their work has also been regularly delayed by bureaucratic demands,
once stopping their collections for two years.
In more than a decade of searching, the group has brought back 2,200
samples from this tributary of the mighty, tea-dark Rio Negro (Black
River) to its laboratory in Sao Paulo, of which about 70 have shown some
effect against tumors. Just those samples have given the team enough
analysis work for 20 years, said Varella, a lanky marathon runner whose
younger brother died of cancer.
"If we can find 70, imagine what a big university with international
resources could do - they could screen for an absurd amount of
diseases," said Varella, who still spends part of his time treating
prisoners in Sao Paulo.
"As well as the impact this could have on human health, it could
bring resources for preservation and to improve the quality of life of
people who live here." Ironically, it was a foreigner who inspired
Varella to begin his search. Robert Gallo, a U.S. researcher and leading
AIDS expert who co-discovered the HIV virus, asked Varella during a trip
to the Amazon in the early 1990s if anyone was researching the medical
potential of the forest.
Among the natural products being used to fight cancer today is Taxol,
a chemotherapy drug that comes from the bark of the Pacific yew tree.
David Newman, head of the Natural Products Branch of the U.S.
National Cancer Institute, said several promising cancer drugs derived
from natural sources as varied as a deep-water sponges and microbes are
currently going through clinical trials. Often the natural compounds are
tweaked or mimicked to better fight cancer cells.
"It's a detective story and a jigsaw puzzle, but you don't know how
many pieces there are or what the picture looks like," he said. "In one
teaspoon of soil from the Amazon, you find over a thousand microbes that
have never been isolated."
Reuters
|