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Cancer Cure or Conservation?
Pacific Yew
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Taxus brevifolia
Coniferous tree
Shade tolerant
In undisturbed stands is usually found as
an understory tree
• Slow growing
• Pacific yew rarely exceeds 24” in d.b.h.,
and 49 ft in height. The largest on record is
56” in d.b.h., and 60 ft in height.
Pacific Yew
• Shade Tolerant
• Understory
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"Conifer" -"to bear cones“
Cones are sort of like a flower.
Leaves - needles or scale-like.
Drop their leaves (deciduous) in autumn.
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http://images.google.com/images?hl=en&q=pacific+yew&um=1&ie=UTF8&sa=X&oi=image_result_group&resnum=4&ct=title
• Shade tolerance is an ecological concept
that refers to plants' abilities to tolerate low
light levels.
• Able to thrive in the shade, and in the
presence of natural competition by other
plants.
Pacific Yew
Pacific Yew
Age
(years)
25
50
75
100
125
Diameter 6” ab gr
(inches)
1
2
4.5
6
9
Pacific Yew
• Significant numbers of Pacific yew trees
are found in old-growth forests on federal
lands in the Pacific northwest
• Before the importance of taxol was
discovered, the Pacific yew was
considered a trash tree and was often
burned in slash piles after timber
operations
Pacific Yew
Taxol
• Generic name: Paclitaxel
• anti-cancer chemotherapy drug
• Taxol was isolated from the bark of the pacific
yew in 1971
• Taxol is used for the treatment of breast,
ovarian, lung, bladder, prostate, melanoma,
esophageal, as well as other types of solid
tumor cancers. It has also been used in
Kaposi's sarcoma.
Taxol – How Does It Work?
• Cancerous tumors are characterized by cell
division, which is no longer controlled as it is in
normal tissue.
• "Normal" cells stop dividing when they come into
contact with like cells, a mechanism known as
contact inhibition. Cancerous cells lose this
ability.
• Cancer cells no longer have the normal checks
and balances in place that control and limit cell
division.
Taxol – How Does It
Work?
• The ability of chemotherapy to kill cancer cells
depends on its ability to halt cell division.
• Usually, the drugs work by damaging the RNA or
DNA that tells the cell how to copy itself in
division.
• If the cells are unable to divide, they die.
Taxol – How Does It Work?
• Taxol is an antimicrotubule agent
• Antimicrotubule agents inhibit the microtubule
structures within the cell.
• Microtubules are part of the cell's apparatus for
dividing and replicating itself.
• Inhibition of these structures ultimately results
in cell death.
Taxol – What’s it Worth?
• To date, Taxol is the best-selling cancer
drug ever manufactured. Annual sales of
the drug peaked in 2000, reaching $1.6
billion
• Bristol-Myers Squibb was given exclusive
rights to provide Taxol from T. brevifolia
under a cooperative research and
development agreement with the U.S.
government in 1991.
What Does Taxol Cure?
• Ovarian Cancer
– Cancer that forms in tissues of the ovary.
Most ovarian cancers are either ovarian
epithelial carcinomas (cancer that begins in
the cells on the surface of the ovary) or
malignant germ cell tumors (cancer that
begins in egg cells).
• In 2007
– New Cases: 22,430
– Deaths: 15,280
What Does Taxol Cure?
• Breast Cancer
– Cancer that forms in tissues of the breast,
usually the ducts (tubes that carry milk to the
nipple) and lobules (glands that make milk). It
occurs in both men and women, although
male breast cancer is rare.
• In 2007
– New Cases: 178,480 (females), 2,030 (males)
– Deaths: 40,460 (females), 450 (males)
What Does Taxol Cure?
• Breast Cancer
– 12.7 percent of women born in the United
States today will develop breast cancer at
some time in their lives
– “1 in 8”
What Does Taxol Cure?
• Lung Cancer
– Cancer that forms in tissues of the lung,
usually in the cells lining air passages.
• In 2007
– New Cases: 213,380
– Deaths: 160,390
Melanoma
•Skin cancer
•It is due to uncontrolled
growth of pigment cells,
called melanocytes.
Kaposi's sarcoma
•Kaposi's sarcoma (KS) is a tumor caused by
Human herpesvirus 8 (HHV8), also known as
Kaposi's sarcoma-associated herpesvirus (KSHV).
•It became more widely known as one of the AIDS
defining illnesses in the 1980s.
•Although KS is now well-established to be caused
by a virus infection, there is widespread lack of
awareness of this even among persons at risk for
KSHV/HHV-8 infection
Native American Uses of the
Pacific Yew
• Used for the manufacture
of bows, arrows,
harpoons, spear handles,
paddles, war clubs,
digging sticks, wedges,
boxes, drums, spoons,
dishes, cups, and bowls.
• The fragrant foliage was
used as a deodorant and
cleaning agent
Native American Uses of the
Pacific Yew
• Some American Indian peoples traditionally associated
Pacific yew with death and bereavement.
• Tonics made from Pacific yew were used medicinally by
many peoples of the Pacific Northwest.
• Some Native American tribes in Washington used the
yew boughs and needles for symbolic building of body
strength.
• Quinault tribe used the Pacific Yew as medicine for a
broad range of ailments
• Several tribes also have dried the needles for smoking,
either in combination with other products or later with
tobacco (caused dizziness).
Native American Uses of the
Pacific Yew
• Saanich Tribal women used Pacific yew to
remove underarm hair
• Okanagans made a red paint from ground
yew wood mixed with fish oil
• Haidas believed that women who ate yew
berries would not conceive.
Pacific Yew Act
• The public outcry against the proposed
harvesting of T. brevifolia trees and shrubs
in federal lands in California, Idaho,
Montana, Oregon, and Washington led to
the Pacific Yew Act and increased
awareness and regulation of bioprospecting worldwide.
Pacific Yew Act
• The purpose of this Act is to ensure
maintenance of the supply of Pacific yew
for medicinal uses.
• The Secretaries of Agriculture and the
Interior are given broad powers to ensure
the minimization of the illegal harvest and
sale of the Pacific yew, and to negotiate
the sale of Pacific yew growing under their
jurisdiction.
Pacific Yew Act
• The Act requires the Secretaries concerned to
pursue a conservation and management policy
with respect to lands and interests in lands
under the jurisdiction of the Forest Service or the
Bureau of Land Management which contain the
Pacific yew.
• The policy must provide for the sustainable
harvest and long-term conservation of the
Pacific yew, with consultation as necessary
under the Endangered Species Act to determine
the effect of harvesting on endangered and
threatened species and critical habitat
Assignment
• If you were in Jim Redwood’s position,
how would you vote and why? This case
study is a question of ethics so there is no
“correct” answer, but you must justify your
position.
• Please limit your response to one
paragraph (no more than a ½ page long
typed).
• This assignment is due next week at the
beginning of lab.