Roundup Cancer Study 2018-03-01T13:07:03+00:00

Roundup Cancer Study – Published Research

Lymphoma Link Confirmed in Large Swedish Roundup Cancer Study

In this 2002 Roundup cancer study, three experienced Swedish cancer researchers combined data from their two previous studies to assess whether there is a link between Roundup (glyphosate) and non-Hodgkin lymphoma (NHL).

Earlier Glyphosate Studies

In an earlier Roundup cancer study, Dr. Marie Norström and Dr. Lennart Hardell compared exposure to herbicides (including Roundup glyphosate), insecticides, fungicides and other toxins in two populations: 111 male cases with hairy cell leukemia (HCL), a type of non-Hodgkin lymphoma, and 400 subjects who did not have the disease. Those with the disease are referred to as “cases”; those without the disease are called “controls.” Their findings were published in 1998 in the British Journal of Cancer.

In March 1999, Dr. Hardell teamed up with Dr. Mikael Eriksson to publish a second Roundup cancer study in the journal Cancer. In that study, they compared 404 individuals who had been diagnosed with non-Hodgkin lymphoma with 741 control subjects that had no such diagnosis. By means of detailed questionnaires mailed to the participants, the researchers gathered data on herbicides (including glyphosate), insecticides and other toxins to which the subjects were exposed. Follow-up telephone interviews were conducted to supplement the written responses. Information was obtained on the years of exposure and cumulative exposure in days. All interviews and the coding of the interview answers were blinded. In other words, it was not disclosed whether the person being interviewed was a case (someone diagnosed with non-Hodgkin lymphoma) or a control.

Both of these earlier studies linked Roundup (glyphosate) to cancer. The 1998 Roundup cancer study reported that exposure to herbicides, including glyphosate, significantly increased the risk of HCL. The risk almost tripled.

The 1999 study found that exposure to herbicides, including glyphosate, increased the risk for non-Hodgkin lymphoma. The authors reported that exposure to both Roundup (glyphosate) and other herbicides increased risks for non-Hodgkin lymphoma and recommended continuing epidemiologic studies on glyphosate.

2002 Roundup Cancer Study

For their 2002 study, Hardell and his colleagues combined data from the cases and controls in their 1998 and 1999 studies. The larger number of cases and increased pool of data allows researchers to more accurately detect an effect that might not been seen when analyzing a relatively small number of cases. In total, data on 515 men with NHL or HCL and 1,141 controls were examined for the 2002 Roundup cancer study.

Results from the pooled analysis confirmed findings from the previous two studies. The scientists found increased risks for non-Hodgkin lymphoma associated with exposure to herbicides, insecticides and fungicides. The authors reported that significant associations were found for glyphosate. The data suggested that exposure to Roundup could triple the risk of non-Hodgkin lymphoma.

Hardell and Eriksson continued their work and published a fourth Roundup cancer study in 2008 in the International Journal of Cancer. Again they found Roundup (glyphosate) was associated with a statistically significant increased risk for lymphoma. (See study below.)

Summary Information

Exposure to Pesticides as Risk Factor for Non-Hodgkin’s Lymphoma and Hairy Cell Leukemia: Pooled Analysis of Two Swedish Case-control Studies

Lennart Hardell1.2, Mikael Eriksson3 & Marie Nordström1

  1. Department of Oncology, Örebro University Hospital, Örebro, Sweden
  2. Department of Natural Sciences, Örebro University, Örebro, Sweden
  3. Department of Oncology, University Hospital, Lund, Sweden

Leukemia and Lymphoma, 2002; 43(5): 1043-1049.

Contract grant sponsors: The Swedish Cancer Research Fund, the Swedish Medical Research Council, Örebro County Research Committee and Örebro Medical Centre Research Foundation.

2003 De Roos Pesticide Non-Hodgkin’s Lymphoma Study

In this study, researchers analyzed data that was originally gathered by the National Cancer Institute (NCI) in the 1980s. As part of its investigation into the association between pesticide exposure and non-Hodgkin’s lymphoma in men, the NCI conducted three case control studies; one in Nebraska, one in Iowa and Minnesota, and one in Kansas. In case control studies, individuals with a disease, the cases, are compared to subjects without the disease, the controls. The goal is to determine if the cases were exposed to certain substances much more frequently than the controls. Researchers can use the data to estimate how much exposure to the substance increases the risk of acquiring the disease.

De Roos and his group, which included a number of scientists who had been involved in the three original studies, wanted to explore the effect of exposure to multiple pesticides (the pesticide group includes insecticides and herbicides like Roundup) on NHL risk. The researchers analyzed data from 870 cases and 2,569 controls. Men in both groups were interviewed about their exposure to agricultural pesticides and other risk factors for NHL. Forty-seven insecticides and herbicides were examined.

De Roos reported that nine pesticides, including glyphosate, were associated with increased incidence of non-Hodgkin’s lymphoma. It is significant that only nine of the 47 pesticides were linked to NHL. This, says De Roos, suggests that the findings for these pesticides were not simply the result of recall bias (inaccuracies in the recall of the subjects interviewed) or bias related to the selection of the 47 pesticides analyzed in the study. In other words, the association of these nine pesticides with NHL did not just happen by chance or because of a fault with the way the study was conducted. The high toxicity of these pesticides can be seen in the fact that four of them (fonofos, chlordane, dieldrin and copper acetoarsenite) have since been banned in the United States. A fifth, diazinon, used to be a popular insecticide, but can no longer be purchased by consumers due its health risks to humans, particularly children. Yet another (atrazine) was banned in the European Union. This is the exclusive “club” of which glyphosate was discovered to be a member.

When De Roos restricted her analysis to just these nine “potentially carcinogenic” pesticides, she discovered a significant trend. The more of these pesticides a subject used, the more the NHL incidence increased. Subjects who used five or more of the nine pesticides were “twice as likely to be NHL cases than controls.” It turned out that glyphosate was a special ingredient in this “stew” of highly toxic pesticides. When De Roos removed it and repeated the analysis with just eight pesticides, the trend towards increasing NHL incidence when an increased number of pesticides was used disappeared.

De Roos makes an important point at the conclusion of this study. For regulatory purposes, government agencies necessarily focus on pesticides individually. But risks to the public are often amplified by exposure to multiple pesticides. Protecting public health must involve an assessment of pesticides not just individually, but as they are used in possible combination with other pesticides.

Summary Information

Integrative assessment of multiple pesticides as risk factors for non-Hodgkin’s lymphoma among men

A J De Roos1, S H Zahm1, K P Cantor1, D D Weisenburger2, F F Holmes3, L F Burmeister4, A Blair1

  1. Division of Cancer Epidemiology and Genetics, National Cancer Institute, USA
  2. University of Nebraska Medical Center, Omaha, NE, USA
  3. Kansas University Medical Center, Kansas City, KS, USA
  4. University of Iowa College of Medicine, Iowa City, IA, USA

Occupational and Environmental Medicine and Chemical Toxicology; 60 (9), September 2003


No information provided.


2008 Roundup Cancer Study

This Roundup cancer study, the fourth in a decade-long series of Swedish studies examining the link between glyphosate and non-Hodgkin lymphoma (NHL), provided additional support to the findings of the previous three studies. (See study review above.)

The principal investigators in this Roundup cancer study, oncologists Mikael Eriksson and Lennart Hardell, have been researching the link between herbicides and non-Hodgkin lymphoma since 1981 and have collaborated on two previous studies of cancer-causing pesticides. (The term “pesticides” encompasses insecticides and herbicides.) Both studies linked glyphosate to non-Hodgkin lymphoma. In this study 910 subjects (534 males and 376 females) diagnosed with non-Hodgkin lymphoma were compared to 1,016 controls. Through questionnaires and interviews, Ericksson and Hardell obtained information on exposure to pesticides and herbicides, including number of years and days of exposure and length of exposure per day. They found that exposure to glyphosate doubled the risk of non-Hodgkin lymphoma.

The authors noted that the association between glyphosate and NHL “was strengthened by a tendency to dose-response effect…” This means that the longer a person was exposed to glyphosate (the dose), the greater the increase in risk of lymphoma (response). A dose-response effect is an important indicator of a causal relationship.

Summary Information

Pesticide Exposure as Risk Factor for Non-Hodgkin Lymphoma Including Histopathological Subgroup Analysis

Mikael Eriksson1, Lennart Hardell2, Michael Carlberg2, Måns Åkerman3

  1. Department of Oncology, University Hospital, Lund, Sweden
  2. Department of Oncology, University Hospital, Örebro, Sweden
  3. Department of Pathology, University Hospital, Lund, Sweden

International Journal of Cancer, 2008; 123(7): 1657-1663.

Grant sponsors: Canceroch Allergifonden, Nyckelfonden, Örebro University Hospital Cancer Fund.


2013 Glyphosate Breast Cancer Study

A study published in the June 2013 edition of Food and Chemical Toxicology found that glyphosate drives breast cancer proliferation. Researchers in Thailand compared glyphosate’s effect on both hormone-dependent and hormone-independent breast cancer cell lines, finding that the herbicide stimulates hormone-dependent cancer cell lines in “low and environmentally relevant concentrations.

Specifically, the glyphosate breast cancer study found that glyphosate can drive estrogen receptor mediated breast cancer cell proliferation in the parts per trillion concentration range. Put simply, infinitesimal concentrations of glyphosate had a carcinogenic effect on the studied breast cancer cell lines (T47D).

Another disturbing finding in the glyphosate breast cancer study was that genistein, a naturally occurring phytoestrogen in soybeans, exhibited “an additive estrogenic effect” when combined with glyphosate. The finding raises more questions about whether genetically-modified soybeans are adding to the breast cancer epidemic in the U.S., where GMO soybeans are heavily consumed.

Summary Information

Glyphosate Induces Human Breast Cancer Cells Growth Via Estrogen Receptors

Siriporn Thongprakaisang 1, Apinya Thiantanawat 2,3, Nuchanart Rangkadilok 1,3,

Tawit Suriyo 3, Jutamaad Satayavivad 1,3,4

1 Environmental Toxicology Program, Chulabhorn Graduate Institute, Kamphaengphet 6 Road, Laksi, Bangkok 10210, Thailand

2 Applied Biological Sciences Program, Chulabhorn Graduate Institute, Kamphaengphet 6 Road, Laksi, Bangkok 10210, Thailand

3 Laboratory of Pharmacology, Chulabhorn Research Institute, Kamphaengphet 6 Road, Laksi, Bangkok 10210, Thailand

4 Center of Excellence on Environmental Health and Toxicology, Office of the Higher Education Commission, Ministry of Education, Bangkok 10400, Thailand

Food Chem Toxicol. 2013 Jun 8. Epub 2013 Jun 8. PMID: 23756170

2013 Paper on Glyphosate Cancer Causation

In a 2013 paper published in the journal Entropy, two scientists familiar with glyphosate’s effects on a wide range of biological processes in plants and animals review the pathways by which glyphosate exposure may contribute to disease in humans, including breast cancer and multiple myeloma. (In multiple myeloma the body continually produces abnormal plasma cells, a type of white blood cell. These cancerous cells accumulate in the bones and damage them.) Authors Anthony Samsel and Stephanie Seneff focus on two main areas in which glyphosate could have negative effects in the human body:

  • Disruption of an important enzyme (Cytochrome P450, or CYP) that plays a critical role in the body’s ability to get rid of unwanted chemicals and environmental toxins.
  • Adverse effects on key bacteria in the digestive tract that are also involved in detoxification and immune system function.

It has been claimed that glyphosate is not toxic to humans, since it harms plants by disrupting a biological process that does not exist in humans. (The process, known as the “shikimate pathway,” is the means by which plants, bacteria, fungi and algae, manufacture certain amino acids, the building blocks of protein.) But that process does exist in the trillions of bacteria in the gastrointestinal tract, or “gut,” and those bacteria play a central role in human health. Doctors tell us that it is important to have a balance of different gut bacteria. When that diversity is upset, inflammation and disease appear to follow.

Citing evidence from animal studies, Samsel and Seneff argue that glyphosate disrupts intestinal tract bacteria creates an imbalance of toxin-producing bacteria in the gut. This leads to chronic inflammation and obesity, both of which are known to be risk factors for many diseases, including several types of cancer.

The authors also discuss glyphosate’s effect on CYP enzymes in the liver. Several different CYP enzymes are essential for one of the liver’s main jobs – ridding the body of toxins. Studies from animals, plants, and human cells demonstrate that glyphosate inhibits the activity of CYP enzymes. This inhibition, Samsel and Seneff believe, results in a disruption of the body’s ability to remove toxins.Two other CYP-dependent processes that take place in the liver – the synthesis of cholesterol and vitamin D3 – may also be affected.

Samsel and Seneff also make an observation that is supported by other researchers: Roundup herbicide is much more toxic than glyphosate alone. Roundup contains additional chemicals (called adjuvants) that assist glyphosate in doing its job. For example, surfactants in Roundup help glyphosate spread across and penetrate the leaf surface. Though glyphosate is said to be the only “active” ingredient in Roundup, scientists have found that surfactants and other adjuvants in Roundup contribute greatly to its toxic effects.

This paper provides a wealth of evidence tying glyphosate’s toxic effects to many common health problems, including diabetes, heart disease, autism, and Alzheimer’s.

Summary Information

Glyphosate’s Suppression of Cytochrome P450 Enzymes and Amino Acid Biosynthesis by the Gut Microbiome: Pathways to Modern Diseases

Anthony Samsel, Independent Scientist and Consultant and Stephanie Seneff, Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA.

Entropy 2013,15,1414-1453

Funded in part by Quanta Computers, Taipei Taiwan, under the auspices of the Qmulus Project

2014 Meta Analysis Roundup Cancer Study

In this 2014 Roundup cancer study, two researchers published the results of their analysis of nearly thirty years of epidemiological research into the link between non-Hodgkin lymphoma (NHL) and exposure to agricultural pesticides on farms and in related occupational settings. They used a statistical procedure known as meta-analysis, in which researchers combine data from several different studies. The increased pool of data and the large number of cases allows scientists to detect significant effects that might not show up in smaller studies.

Forty four papers were included in the meta-analysis. Of these, 20 papers gave estimates of associations with herbicides or active ingredients in herbicides, including glyphosate. The scientists found that several different types of herbicides were associated with non-Hodgkin lymphoma. They included:

  • Phenoxy herbicides (2,4D, MCPA)
  • Aromatic acid herbicides (dicamba)
  • Organophosphorus herbicides (glyphosate)

Ortho® Weed B Gon® weed killer contains three of these chemicals—2,4D, MCPA and dicamba. Spectracide Weed Stop contains 2,4D and dicamba. Glyphosate, of course, is the active ingredient in Roundup.

Schinasi and Leon found significant associations between glyphosate and non-Hodgkin lymphoma and an even stronger association between glyphosate and a common subtype of NHL, B cell lymphoma. (Glyphosate exposure doubled the risk of non-Hodgkin lymphoma.)

“B cell lymphoma was positively associated with … the organophosphorus herbicide glyphosate.”

The authors point out that different subtypes of non-Hodgkin lymphoma may be more likely to be caused by pesticide exposure (including insecticides and herbicides) than others, but relatively few studies examine associations at the subtype level. They believe more studies are needed to determine which subtypes of NHL are most strongly associated with exposure to pesticides.

Summary Information

Non-Hodgkin Lymphoma and Occupational Exposure to Agricultural Pesticide Chemical Groups and Active Ingredients: A Systematic Review and Meta-Analysis

Leah Schinasi and Maria E. Leon, Section of Environment and Radiation, International Agency for Research

International Journal of Environmental Research and Public Health, 23 April 2014; 11(4): 4449-4527.

Grant from the Office National de l’Eau et des Milieux Aquatiques—ONEMA, France.

2012 and 2014 Roundup Animal Study Involving GM Corn

This study, first published in 2012, then retracted, and ultimately republished by a different journal in 2014, is one of the most revealing and controversial studies in the scientific literature that has addressed the safety of Roundup. We’ll begin with the study itself and then move to the controversy. 

Seralini’s study was essentially a follow-up to a Roundup cancer study that had been conducted by Monsanto in 2004 and offered by that company as proof that genetically modified corns sprayed with Roundup are safe. Both studies used the same strain of rats. Both studies examined rats fed grain from “Roundup Ready” corn (NK 603, a corn genetically modified (GM) to tolerate Roundup) that had been sprayed with Roundup.

The 2004 Monsanto study lasted 90 days. The authors reported no statistically significant differences on a variety of tests that compared animals fed grain from Roundup Ready corn and the controls fed grain from non-GM corn. They stated that Roundup Ready corn was safe.

Seralini and his group of scientists, however, were able to obtain the raw data from that study (via the Swedish Board of Agriculture after a request from Greenpeace Denmark) and subject it to a detailed analysis. Their 2009 study revealed a number of significant effects that pointed to toxicity and dysfunction in several organs (heart, kidney and liver) in the rats fed Roundup Ready grain. Seralini and his group wanted to know what would happen if the rats were maintained on the Roundup Ready grain diet for a longer period of time. Would they develop serious diseases? That question led to Seralini’s 2012 follow-up study.

In the follow-up study, rats were followed for two years. Seralini expanded the study to include three treatment groups:

  • Rats fed genetically modified corn that was not treated with Roundup
  • Rats fed GM corn treated with Roundup
  • Rats given Roundup alone at “low environmentally relevant doses,” administered via drinking water.

It is significant that Seralini’s study exposed the animals to the entire Roundup formulation, not just to glyphosate, the stated “active ingredient” in Roundup. The entire formulation contains chemicals added to Roundup (termed “adjuvants” and “surfactants”) that have been found to enhance the toxic effects of the herbicide.

The results of Seralini’s two-year study were alarming. According to the researchers, “Biochemical analyses confirmed very significant chronic kidney deficiencies, for all treatments and both sexes.” Liver disease also increased significantly. In females, there was a two to three-fold increase in mortality and the deaths were earlier. Seralini’s group called for additional research to explore the long term consequences of exposure to Roundup and consumption of genetically modified foods.

“Our data highlight the inadequacy of 90-day feeding studies and the need to conduct long-term (2 years) investigations to evaluate the life-long impact of GM food consumption and exposure to complete pesticide formulations.”

Gilles-Eric Séralini et al., “Republished study: long-term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize,” Environmental Science Europe, June 2014

There is now considerable evidence that Monsanto responded to the publication of the study by immediately launching a media and letter-writing campaign to have Seralini’s work discredited and his study retracted by the journal that published it. Documents obtained through legal action show that the editor of the journal that retracted the study had close ties, including a consulting agreement, with Monsanto. Monsanto’s media assault demonstrates the power the biotech industry can exercise when science threatens its profitability. A 2012 article written by Jonathan Matthews, the founder of GM Watch, described the lengths to which Monsanto and its industry allies will go to squash researchers who stand it their way.

In a detailed reply their critics, Seralini and his team noted that 75% of the criticisms offered the first week after his original study was published came from plant biologists, some of whom are developing patents for genetically modified plants, and from Monsanto.

In one of the few letters not linked to the biotech and chemical industries, Jack Heinemann, the director of the Centre for Integrated Research in Biosafety, University of Canterbury, New Zealand, made a cogent point regarding the journal that published, and ultimately retracted, Seralini’s study. He found seven studies, in addition to Seralini’s study, that were published in that journal between 2004 and the date of his letter (November 2012), in which the same strain of rats Seralini used were fed diets supplemented with material from genetically modified plants. All were 90-day studies published by companies who developed the genetically modified plant used in the study.

Ultimately the study was retracted, with no reasonable explanation given other than to say the results of the study “(while not incorrect) are inconclusive.” This explanation is absurd on its face. Inconclusive research is indispensable to the advance of science. It is published every day. Two professors at Georgetown University Medical Center called the retraction “a black mark on scientific publishing, a blow to science, and a win for corporate bullies.”

The study was republished in June 2014 by Environmental Sciences Europe.

Summary Information

First Publication (retracted)

Long-term toxicity of a Roundup herbicide and a Roundup tolerant genetically modified maize

Gilles-Eric Sérallini1, Emilie Clair1, Robin Mesnage1, Steeve Gress1, Nicholas Defarge1, Manuela Malatesta2, Didier Hennequin3, Joël Spiroux de Vendômois1

  1. University of Caen, Institute of Biology, CRIIGEN and Risk Pole, MRSH-CNRS, EA 2608, Esplanade de la Paix, Caen Cedex 14032, France.
  2. University of Verona, Department of Neurological, Neuropsychological, Morphological and Motor Sciences, Verona 37134, Italy.
  3. University of Caen, UR ABTE, EA 4651, Bd Maréchal Juin, Caen Cedex 14032, France.

Food and Chemical Toxicology; 50 (11), 4221-4231, November 2012


Authors acknowledge the Association CERES, the Foundation ‘‘Charles Leopold Mayer pour le Progrès de l’Homme’’, the French Ministry of Research, and CRIIGEN for their major support.

Second Publication (republished)

Republished study: long-term toxicity of a Roundup herbicide and a Roundup tolerant genetically modified maize

Gilles-Eric Sérallini1, Emilie Clair1, Robin Mesnage1, Steeve Gress1, Nicholas Defarge1, Manuela Malatesta2, Didier Hennequin3, Joël Spiroux de Vendômois1

  1. University of Caen, Institute of Biology, CRIIGEN and Risk Pole, MRSH-CNRS, EA 2608, Esplanade de la Paix, Caen Cedex 14032, France.
  2. University of Verona, Department of Neurological, Neuropsychological, Morphological and Motor Sciences, Verona 37134, Italy.
  3. University of Caen, UR ABTE, EA 4651, Bd Maréchal Juin, Caen Cedex 14032, France.

Environmental Sciences Europe; 26 (1):14, June 2014


Authors acknowledge the Association CERES, the Foundation ‘‘Charles Leopold Mayer pour le Progrès de l’Homme’’, the French Ministry of Research, and CRIIGEN for their major support.

International Agency Research on Cancer

2015 IARC Roundup Cancer Study

In 2015, the International Agency for Research on Cancer (IARC) published the results of a year-long investigation into the link between several different insecticides and herbicides, including glyphosate and cancer. The group concluded that glyphosate is “probably carcinogenic to humans.”

For a more detailed review of the IARC monograph on glyphosate, as well as the Roundup cancer study summary and links to the monograph itself, please refer to the IARC glyphosate study page.