Roundup Cancer Study 2016-11-10T16:10:56+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.


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.

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.