GMW: Don't be deluded that this is the cancer breakthrough

[Guest guest]

GMW: Don't be deluded that this is the cancer breakthrough

" GM WATCH " <info

Sun, 3 Sep 2006 13:47:34 +0100

 

 

 

 

GM WATCH daily

http://www.gmwatch.org

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" It's like walking on a waterbed: resolve one problem and five or six

others pop up somewhere else. " - Professor Bruce Ponder

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Don't be deluded that this is the cancer breakthrough

Last week's news of a melanoma 'cure' is the latest in a series of

advances that lack staying power, says John Cornwell

The Sunday Times, Sep 3 2006

http://www.timesonline.co.uk/article/0,,2092-2340052,00.html

 

It's been a heady fortnight for medical science. First there was

thrilling news from the great stem cell bazaar. The boffins, it was

claimed

by the US biotech company Advanced Cell Technology, had got around a

tricky ethical conundrum that would now allow researchers to experiment

with human stem cells without actually killing off viable human embryos.

Stem cell research could go full steam ahead to the final frontiers -

cures for everything from damaged spinal cords to blindness - free of

George Bush's evangelical scruples.

 

Hot on the heels of this comes a revival of the fortunes of that other

" Next Big Thing " that never quite made it despite an ethical clean bill

of health (save that the cure all too often turned out worse than the

disease). The return of gene therapy.

 

Two dying men with malignant melanoma, it was announced on Friday in

the American journal Science, had been cured after their genetically

engineered white blood cells turned into " cancer hunters " and mopped up

proliferating malignant cells. If it works for this virulent form of skin

cancer, argue the exultant scientists, then it could work for other

cancers.

 

But before cracking open the champagne, there's more than a shiver of

deja vu about the news. Is this the same gene therapy that was promised

in the dying days of the old century? The $3 billion Human Genome

Project, widely announced as the cracking of nature's code, was promoted

through the 1990s as the beginning of the end of the 4,000 diseases that

affect humankind: just find the faulty gene, send in a harmless carrier

virus to knock it out or correct it, and Bob's your uncle.

 

Well, there was clearly no doubt genetic testing would reveal many of

the secrets of the human body: including breakthroughs in isolating

genes for specific cancers or who was likely to get Huntington's disease,

or early heart disease, or diabetes - if you really wanted to know. But

gene " therapy " was another matter.

 

On the eve of the millennium an Arizona teenager, Jesse Geslinger,

suffering from a mild form of ornithine transcarbamylase deficiency,

which

affects the body's ability to process ammonia, volunteered for genetic

therapy at the University of Pennsylvania. A gene correction aimed at

curing him was attempted in the form of an engineered " carrier " virus

injected into his liver. He developed an infection and three days later

he was dead.

 

It was a tragedy not only for Jesse's family but for the entire genetic

medical science community. But genetic therapy researchers held their

breath and tried again. The following year, 2000, two infants suffering

from SCID (severe combined immunodeficiency disorder), causing them to

live inside bacterium-free bubbles, were treated by a similar gene

" correction " strategy at Necker hospital in Paris.

 

In October 2002 one of the children was found to have leukaemia. When

the second child developed leukaemia a year later the trials were

halted. As James Watson, co-discoverer of the structure of DNA, remarked

laconically: " Gene therapy seems to have cured the children's SCID but

caused leukaemia as a side effect. "

 

The record of gene therapy, so far, should give us pause before

rejoicing over the melanoma cures in the US. In the first place they

were just

two claimed successes out of 17 similarly treated patients, and

melanoma has a way of coming back after a patient has been declared

free of

it. In the second, scientists in the business of battling with cancer

these past 40 years have given up on discovering anything like a magic

bullet.

 

Winning the war against cancer, as the preponderance of the world's

oncologists repeatedly stress, is a long hard slog on a great many

fronts.

The surest and longest-term successes appear to be in the middle ground

of hormone and protein research rather than at the level of genes: the

kind of strategies that have made Herceptin, the breast cancer drug, an

apparent success.

 

As Professor Bruce Ponder, one of the British contributors to the

discovery of the BRCA1 and BRCA2 breast cancer genes, tells me: " We have

come a long way in the past two decades and what we see is dauntingly

complex. It's like walking on a waterbed: resolve one problem and five or

six others pop up somewhere else. It is not one disease, it's hundreds. "

 

Ponder's belief in the multi-dimensional nature of cancer and its

treatment is a crucial aspect of his direction of one of the largest

cancer

research sites in Europe at Cambridge, where 500 scientists will

eventually be studying the disease in collaboration with clinicians.

Genetic

therapy is a crucial and continuing part of the war, he avers - he is,

after all, a geneticist.

 

But three years back, on the 50th anniversary of his great discovery

with Francis Crick, Watson reflected sadly on the fact that genetic

therapy had not lived up to anything like its great expectations.

" Diagnostics, " he declared, " are now our most powerful weapons . . .

in the case

of prenatal diagnosis it is the prospective mother who should make the

decisions. "

 

Which brings us, ironically, back to an ethical connection between

genes and stem cells. The supposed breaking of the moral scruple of human

embryonic research involves the discovery that it is possible to extract

a single cell from the embryo at the 8-cell stage of development and to

nurture that extracted cell into a stem-cell line for potential

therapies. Such extractions are being done routinely in diagnostic

testing of

embryos for suspected genetic faults such as Down's syndrome; and

objections persist.

 

Those who would quarrel with prenatal diagnostic testing as well as

human embryonic experiment form, of course, a much wider constituency

than

George Bush and the Pope. Discovery of Down's syndrome in prospect, or

cystic fibrosis, is one thing. But where, ask many ethicists, does it

end? Choice of sex? Colour of eyes?

 

Furthermore, there are as yet no controlled experiments to prove that

individuals who have grown from embryos deprived of a cell at the 8-cell

stage will be normal. One can only speculate about the day when an

accused villain in the dock cops the plea that his embryo was deprived

of a

crucial totipotent stem cell.

 

 

 

 

 

 

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