AngryToxicologist is a scientist in the public health sector, knows plenty about toxicology, and is occasionally angry about it all. Drop me a line at Read some background on PFOA and Teflon here.
A couple of years ago DuPont and other perfluorochemical industries were dismissing evidence of PFOA-caused cancer in rats, saying it was due to peroxisome proliferation in rats, which some argue isn't relevant to humans. However, PFOA may have other mechanisms of action (disrupting thyroid hormones, gap junctions, and estradiol among them). You can read more about the evidence in this EWG submission to the EPA. Well, EPA must not have payed too much attention to those other mechanisms because they basically ignored them and wanted to discount the cancer. In fact, they didn't do a cancer risk assessment at all. The EPA's draft risk assessment isn't very good but it does contain most of the background info if you're interested.
Speeding forward to now, we have a paper in EHP showing that PFOA causes liver cancer in trout without causing peroxisome proliferation. In fact, it finds that PFOA administration leads to changes similar to, you guessed it, estradiol.
Gee, look how that turned out. Not as if a scientist should need convincing of this but...Never ignore data, it will turn around and make you look like a fool someday.
Medicine & Health
Comments
hm, rats, trout, ... American kitchens are full of peeling teflon pans. Plenty of teflon has gone down my gullet.
Posted by: llewelly | August 5, 2008 9:20 AM
"PFOA causes liver cancer in trout..."
well, the paper says pfoa promotes tumours when you give the trout a swingeing dose of aflatoxin B1 first.
"PFOA administration leads to changes similar to, you guessed it, estradiol"
so what ? the R is only 0.8, which allows plenty of other gene changes. Where is the evidence that the estrogen-like effect has anything to do with cancer ?
so pfoa has not been shown to cause cancer in trout; and I do not understand why you care either ? Perhaps if you could make that clear ?
per
Posted by: per | August 7, 2008 1:25 PM
So, per, the significance for this paper isn't that much alone but only to show that it dose cause estradiol-like changes while leading to liver tumors. The reason that is so important is that tumors in multiple organs (including breat) have been identified in rats but has always been dismissed as perioxisome proliferation(PP) that is not relevant to humans. This study adds significantly to the other literature showing that PFOA is likely causing tumors by a non-PP method. So if you tie all the cancer and mechanism of action info together with this paper, it really starts to mean something.
Posted by: Angrytoxicologist | August 8, 2008 12:54 PM
Yeah, and they claimed that PFOA wasn't a bioaccumulative toxin, as well. Ask the polar bears how that one turned out.
Posted by: Tlazolteotl | August 15, 2008 3:00 PM
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Posted by: erotikshop | January 17, 2009 4:26 AM
so pfoa has not been shown to cause cancer in trout; and I do not understand why you care either ? Perhaps if you could make that clear ?
Posted by: Abercrombie | November 30, 2009 10:00 PM