Tamoxifen and Breast Cancer

Larry Caldwell larryc at teleport.com
Wed Sep 16 13:53:53 EST 1998


In article <35FFD0E0.5481 at livingston.net>, dstaples at livingston.net 
says...
> dwheeler at teleport.com wrote:

> > The following appeared in The Oregonian, September 15, 1998, pA10 BTW,
> > tamoxifen is derived from Pacific yew (Taxus brevifolius), and is also known
> > as taxol. Pacific yew is a very slow-growing tree of the Pacific Northwest. A
> > 400-year-old tree may be 12 inches dbh, and contain enough taxol to treat a
> > single cancer patient.

Not all that slow growing.  I have worked with the wood, and while the 
grain is dense, you get nowhere near 66 rings/inch.  10 to 12 rings per 
inch is more like it.  This makes a 12 inch tree no more than 70 years 
old.

Most of the slow growth is due to it being an understory tree that gets 
little light.  Plant it in the open and it grows almost as fast as a fir.

> Taxol has been synthasized and is no longer dependent on natural
> sources.

Sortakindamaybe.  They found that the green parts of the tree have even 
more tamoxifen than the bark, so they started doing single cell slurry 
cultures.  Essentially they take a tree apart into single cells, which 
divide rapidly in a nutrient bath.  So taxol still comes from the Pacific 
Yew, it just does it in a vat rather than the forest.  Good thing, or the 
demand for taxol would have led to the extinction of the yew in short 
order.

They're also using taxol as a base in crafting designer drugs with 
similar modes of action against other types of tumors.

-- Larry



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