A review of the carcinogenic potential of glyphosate by four independent expert panels and comparison to the IARC assessment.
The International Agency for Research on Cancer (IARC) published a monograph in 2015 concluding that glyphosate is "probably carcinogenic to humans" (Group 2A) based on limited evidence in humans and sufficient evidence in experimental animals. It was also concluded that there was strong evidence of genotoxicity and oxidative stress. Four Expert Panels have been convened for the purpose of conducting a detailed critique of the evidence in light of IARC's assessment and to review all relevant information pertaining to glyphosate exposure, animal carcinogenicity, genotoxicity, and epidemiologic studies. Two of the Panels (animal bioassay and genetic toxicology) also provided a critique of the IARC position with respect to conclusions made in these areas. The incidences of neoplasms in the animal bioassays were found not to be associated with glyphosate exposure on the basis that they lacked statistical strength, were inconsistent across studies, lacked dose-response relationships, were not associated with preneoplasia, and/or were not plausible from a mechanistic perspective. The overall weight of evidence from the genetic toxicology data supports a conclusion that glyphosate (including GBFs and AMPA) does not pose a genotoxic hazard and therefore, should not be considered support for the classification of glyphosate as a genotoxic carcinogen. The assessment of the epidemiological data found that the data do not support a causal relationship between glyphosate exposure and non-Hodgkin's lymphoma while the data were judged to be too sparse to assess a potential relationship between glyphosate exposure and multiple myeloma. As a result, following the review of the totality of the evidence, the Panels concluded that the data do not support IARC's conclusion that glyphosate is a "probable human carcinogen" and, consistent with previous regulatory assessments, further concluded that glyphosate is unlikely to pose a carcinogenic risk to humans.
a Department of Pathology , New York Medical College , Valhalla , NY , USA.
Gary M
GM
Williams
b Marilyn Aardema Consulting, LLC , Fairfield , OH , USA.
Marilyn
M
Aardema
c Department of Clinical Epidemiology , Aarhus University , Aarhus , Denmark.
John
J
Acquavella
d Department of Pathology, Queen Mary, University of London , London , UK.
Sir Colin
SC
Berry
e Toxicology Consultant , Bumpass , VA , USA.
David
D
Brusick
f Boston Children's Hospital , Boston , MA , USA.
Michele M
MM
Burns
g Department of Pathology , Botucatu Medical School, São Paulo State University, UNESP , São Paulo , Brazil.
Joao Lauro Viana
JLV
de Camargo
h Department of Occupational Medicine and Epidemiology, EpidStat Institute, University of Michigan , Ann Arbor , MI , USA.
David
D
Garabrant
i Department of Toxicology and Environmental Hygiene , Technical University of Munich , Munich , Germany.
Helmut A
HA
Greim
j Private Consultant , Buena Vista , CO , USA.
Larry D
LD
Kier
k Kirkland Consulting , Tadcaster , UK.
David J
DJ
Kirkland
l Department of Biostatistics , Center for Occupational Biostatistics & Epidemiology, Graduate School of Public Health, University of Pittsburgh , Pittsburgh , PA , USA.
Gary
G
Marsh
m Centre for Toxicology, University of Guelph , Guelph , ON , Canada.
Keith R
KR
Solomon
n Department of Occupational Epidemiology , University of Birmingham , Birmingham , UK.
Tom
T
Sorahan
o Intertek Regulatory & Scientific Consultancy , Mississauga , ON , Canada.
Ashley
A
Roberts
p DLW Consulting Services, LLC, University of New Mexico School of Medicine , Albuquerque , NM , USA.
Douglas L
DL
Weed
Glyphosate; Roundup; aminomethylphosphoric acid; cancer; genotoxicity; herbicide