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Yew berries. Photo by Liz West. View the photo slideshow for this segment.

Yew berries. Photo by Liz West. View the photo slideshow for this segment.

KUOW News

An Unlikely Hero

Sarah Waller
03/20/2012

All week long, we are bringing you stories about Pacific Northwest trees and the role they play in our region and in our lives. Yesterday, we heard about the reproductive cycle of the gingko tree. Today, we turn to the Pacific yew.

It's not a very heroic looking tree, not like the Northwest's towering cedars and Douglas firs. The yew is scrawny and slow growing, but this unassuming conifer has saved thousands of lives. KUOW's Sarah Waller brings us the story in the next part of our series, "More Than A Tree."



TRANSCRIPT

The Pacific yew is part of the reason why Andrea Jones is alive today. We'll get to that later. But first, Andrea says she'll never forget her first meeting with a yew. She was just eight years old.

Jones: "My sisters and I were playing at a neighbor's house, and we found these berries; beautiful red, growing out of tree that looked like an evergreen tree."

So, Andrea's sisters did what parents dread children will do upon discovering yummy–looking berries in the backyard.

Jones: "They started eating them and saying they were really tasty and they said, 'Oh, you should try one!'"

Andrea didn't try one, and it's a good thing. When her sisters got home, they started vomiting. Yew berries are toxic. Andrea and her sisters were rushed to the hospital. At the time, Andrea had no idea that the tree that made her sisters sick would later help save her life.

I wanted to meet a yew tree for myself, so I headed to the Washington Arboretum. I found one growing in the parking lot.

Nalini Nadkarni: "The scientific name is Taxus brevifolia."

That's Professor Nalini Nadkarni. She's a tree canopy expert who's spent a lot of time studying Pacific yews.

Nadkarni: "It's a conifer, and it looks, actually, even though it's a good specimen, it looks pretty ratty."

This yew is huddled in the shade of another tree. And it does look pretty scruffy.

Nadkarni: "Scruffy is a good word for them. The branches are sort of downward casting, kind of droopy. You see a lot of hanging dead limbs on a yew tree. So, it's just kind of a sad, sad character in some ways."

But, this sad character has become an unlikely hero. It started in 1962. That's when the National Cancer Institute began looking for disease–fighting compounds in nature.

One of the trees they looked at was a Pacific yew growing in Packwood, Washington. Researchers made an extract from the bark and put it in a petri dish with some cancer cells.

Something strange happened: The cancer cells died. There was something in the bark that paralyzed the cells so they couldn't divide.

Nadkarni: "And people went, 'Oh my gosh, this is a really active compound.' Until then, there were several cancers that we really had very little in the way of hope that we could do anything for. So, I think what this presented was new hope."

That hope came in the form of the drug taxol, which is derived from yew bark. But, Pacific yew trees aren't that common. They are sparsely scattered here and there along the Cascade Mountains. And, when taxol began saving lives during clinical trials in the 1980s, demand for the bark skyrocketed.

Nadkarni: "It takes actually 60 pounds of bark — and that would be equivalent to the entire bark of four trees — to make enough taxol for the treatment of one ovarian cancer patient. So they began calling for pounds and pounds and thousands of pounds of this yew bark for these trials. Environmentalists began saying, 'Wait a minute. That's a lot of trees!' And I, as a tree biologist, was really worried about this possibility of eliminating, or even driving to extinction, these Pacific yew trees."

The yew used to be considered the weeds of the forests. Loggers burned them rather than selling them as timber. Now, they were in high demand. The National Cancer Institute gave an exclusive contract to harvest yew bark to a former gun shop owner from Walla Walla. But, he only delivered a fraction of the bark he promised.

Meanwhile, patients on the waiting list for taxol were dying. A solution had to be found. So, scientists went to work. They eventually learned how to recreate the active compound from yew bark in a semi–synthetic form. Yew trees were off the chopping block.

And, that brings us back to Andrea Jones.

Jones: "Well, I was diagnosed with breast cancer three years ago. And when I was undergoing treatment, one of the chemo drugs that I had to take was taxol."

That's the drug from the yew tree; the same tree that almost poisoned her as a child. So, has she forgiven the Pacific yew?

Jones: "I've forgiven the tree, definitely. (laughing) It had such a memorable impression on me as a child, and then here it is saving my life."

Andrea has been cancer free for three years. She's planning on planting a Pacific yew tree in her back yard — and has already started teaching her two kids not to eat the berries.

I'm Sarah Waller for KUOW.

© Copyright 2012, KUOW

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