A pathologist serving as an expert witness for plaintiff Sharlean Gordon on Tuesday told a jury the woman’s non-Hodgkin’s lymphoma was caused by her use of the weed killer Roundup, and described the chemical as a potent toxin.
“It goes into the skin and gets into the tissue and the lymphocytes,” Dr. Dennis Weisenburger said.
Later in the day, defense attorneys sought to portray Weisenburger as a highly paid expert plaintiff witness who was biased. They continued to maintain that cancer happens because of naturally ocurring cell mutations.
The trial in the 21st Circuit Court of Missouri in St. Louis County is being streamed live courtesy of Courtroom View Network.
At issue is glyphosate, the primary ingredient in Roundup, the chemical that kills plants and whether it causes cancer. Weisenburger said the extra ingredients in Roundup make it more toxic than glyphosate alone.
Plaintiff Gordon claims that Roundup caused her to develop NHL, also called large B-cell lymphoma (DLBCL), a rare cancer of the blood. Diagnosed with the disease in 2006, Gordon underwent treatments and the cancer went into remission but recurred requiring further treatments. Gordon was in remission after 2009 but she still has to visit doctors checking for a possible relapse.
The lawsuit seeks damages for medical bills, anxiety, physical pain and suffering caused by the disease including the continuing worry today that it could again recur.
Weisenburger, a retired professor of the University of Nebraska and a researcher with the City of Hope, a California-based cancer treatment center, described pathology as the study of injury to tissues.
“I look at slides and tell the clinician what the disease is,” Weisenburger explained. “I also study the causes of lymphoma.”
Weisenburger said studies looked at animals (mice), human cells and epidemiology.
“My studies of glyphosate showed tumors of many types (in test mice),” Weisenburger added. “There is evidence showing that glyphosate causes disease in mice and humans including non-Hodgkin’s lymphoma.”
The generation of disease in humans was caused by what Weisenburger called “oxidative stress.”
“There is a two-fold increase in risk, you agree?” asked Aimee Wagstaff, Gordon’s attorney.
“Yes,” Weisenburger said.
Weisenburger said obesity is also a cause of NHL and Gordon had been obese, but the risk of her getting cancer from that cause was low.
Weisenburger said the disease has a latency period, the time from exposure to Roundup to the onset of illness. Time periods can vary.
“One-half of people get it (cancer) in the first 20 years and the other half after 20 years,” he said. “Glyphosate is toxic.”
Glyphosate first came on the market in 1973.
“People who used Roundup more than two times a year had a two-fold increase in lymphoma,” Weisenburger said. “That statistic is significant.”
Weisenburger said a substance called “surfactant” designed to help spread glyphosate out over a plant leaf made Roundup more toxic than glyphosate alone.
“You can inhale Roundup as a spray mist, but the most important exposure is on the skin,” he said. “It spreads over a leaf. The same thing happens on the skin. It can penetrate the skin and the surfactant makes it more potent.”
A document exhibited by Wagstaff said that Roundup is 50 to 100 times more genotoxic than glyphosate alone and impacts human tissues, blood, lymph nodes and kidneys, which are all exposed.
Weisenburger authored a 2019 scientific paper which said Roundup is a cause of non-Hodgkin’s lymphoma.
Under cross examination, Monsanto attorney Katherine Hacker displayed a slide that showed hundreds of cancer cells.
“There is nothing you can see here that says this was caused by Roundup,” she said.
“That’s true,” Weisenburger agreed.
“You’re not an oncologist?”
“That’s correct.”
“You don’t look at a patient’s clinical records?”
Weisenburger agreed.
Hacker displayed a document from a 2022 European Chemical Risk Assessment that said there was a weak association between Roundup and the occurrence of NHL.
“You see what the agency said?” Hacker asked.
“Yes,” Weisenburger answered.
The document’s conclusion was that no classification for carcinogenicity was warranted for glyphosate.
Hacker told Weisenburger that he was making $4,000 per day to provide deposition testimony and $5,000 per day with trial testimony. She said the total amounted to $1.8 million.
Weisenburger agreed.
“NHL is a common cancer and DLBCL is the most common kind,” Hacker said.
“Yes.”
Hacker displayed a chart that showed the rate of NHL cases from 1992 to 2020 as a flat line during a time when Roundup use increased.
“A flat line is a flat line, right?” she asked.
“A flat line is flat,” Weisenburger said.
“Two things could be associated with each other (Roundup and cancer), but that doesn’t mean one causes the other,” Hacker said.
Weisenburger called the statement confusing.
During this and other Roundup trials, defense attorneys have relied heavily on an Agricultural Health Study in 2018 and also a finding by the Environmental Protection Agency (EPA) that found no association between glyphosate and cancer. Plaintiff attorneys have cited a finding by the International Agency for Research on Cancer (IARC) that glyphosate is a probable carcinogen.
“The National Cancer Institute funded the Agricultural Health Study,” Hacker said. “You respect the National Cancer Institute.”
“Yes,” Weisenburger said.
“It’s the largest study (of glyphosate) ever conducted.”
“Yes.”
Hacker said the rate of NHL did not increase with the increasing use of glyphosate from the 1990s on.
“I can explain to you why that is,” Weisenburger said. “There are flaws in the study (Agricultural Health).”
Hacker objected and asked that the remark be stricken. Circuit Court Judge Brian May agreed.
“You can’t prove that glyphosate causes cancer in mice,” Hacker said.
“You can’t prove it but it’s a red flag (test findings),” Weisenburger answered.