OAKLAND, Calif. (CN) – Roundup did not cause Alberta Pilliod’s cancer and we’ll likely never know what did, a hematologist told jurors Monday at the start of Monsanto’s defense against the woman’s claims that the weed killer made her sick.
Pilliod was diagnosed in 2015 with a primary central nervous system lymphoma, an aggressive form of non-Hodgkin lymphoma, and she believes that three decades of regular Roundup use caused it.
The hematologist, Dr. Celeste Bello, testified during the trial at the Alameda County Superior Court in Oakland that epidemiological data does not support a link between formulated Roundup and non-Hodgkin lymphoma.
“Based on her records, the cause of her primary central nervous system lymphoma is unknown,” Bello said.
The defense’s expert witness, who works at the Moffitt Cancer Center in Florida, added that 80 to 90 percent of cases of this type of lymphoma are idiopathic, meaning they arise spontaneously for no apparent reason.
Bello said there are only two known causes of the disease: having HIV or a suppressed immune system.
Pilliod was diagnosed four years after her husband Alva, who also has non-Hodgkin lymphoma. The couple both have diffuse large B-cell lymphoma. Alberta’s is concentrated in her brain; Alva’s is all over his body.
The plaintiffs’ experts testified that it could not be a coincidence that a married couple who had lived in the same environment for decades developed similar cancers within a few years of each other, but Bello said Monday that it was not uncommon for couples to spontaneously develop similar cancers.
Bello also testified that Roundup’s primary chemical compound, glyphosate, does not necessarily cause gene mutations that lead to cancer. She said most gene mutations are benign and the mutations that are not so harmless do not always spread and can self-destruct before replicating.
“The majority of mutations are nonsense,” Bello said. “They’re called silent mutations. Just because you’re a mutagen doesn’t mean you’re a carcinogen.”
Carcinogens also do not always lead to cancer, Bello added, because the body can fight them off.
Bello spent much of her testimony disputing the myriad studies that the Pilliods’ attorneys have presented to the jury over the past four weeks, including a study that showed that glyphosate causes genetic damage and one that found an association between repeated glyphosate use and non-Hodgkin lymphoma. Bello criticized some of these studies as reporting data that is not statistically significant.
“In my world, it has to be statistically significant. If not, it doesn’t matter. Anything could have caused it,” Bello said. “I want to report the most valid data, not any data that’s out there.”
The only study Bello said she could support was a 2018 update to the Agricultural Health Study, which examined the effects of pesticides on farmers in the U.S. and found no cancer link between glyphosate and non-Hodgkin lymphoma.
Los Angeles-based attorney Brent Wisner, who represents the Pilliods, noted in his cross-examination that Bello said in her deposition that two pesticides – DDT and malathion – cause non-Hodgkin lymphoma.
Bello said she misspoke and that the two pesticides increase the risk of developing the cancer, but are not known to directly cause it.
“It was my first deposition ever,” Bello said. “I didn’t know that every word would be micro-analyzed. They’re more accurately risk factors.”
Wisner asked Bello how she knows HIV can cause Alberta’s type of cancer. Bello said that in the 1980s, researchers began looking at the drastic increase of that type of cancer and found an association with HIV. She compared this conclusion to the link between lung cancer and smoking.
“You start to see a huge risk increase and you start to think there’s more to it,” she said.
Wisner appeared surprised when Bello said she had never heard of the International Agency for Research on Cancer (IARC) – which declared glyphosate a probable human carcinogen in 2015 – even though that arm of the World Health Organization is said to have written “the Bible” on tumor classification.
He also criticized the doctor’s view on glyphosate and genetic damage.
“We have these scientists at IARC looking at hundreds of studies on genotoxicity, and you looked at three,” he said.
Bello said she agreed with the Environmental Protection Agency’s conclusion that glyphosate is not likely to be carcinogenic to humans, but Wisner asked Bello if she knew that agency’s report was based, at least in part, on “fraudulent data.”
“I have no reason to question their statements,” Bello said.
When asked about invalid studies by the now-defunct Industrial Bio-Test (IBT) Laboratories that led to Roundup’s approval for sale in 1974, Bello said, “I don’t even know what IBT is.”
Wisner also picked apart the Agricultural Health Study, in which roughly 52,000 people self-reported their level of exposure to glyphosate from 1993 to 1997. Researchers did follow-up phone interviews with participants between 1999 and 2003, and again between 2005 and 2010.
The number of participants in the study dwindled over the years, and the amounts of glyphosate the participants used went up as the chemical grew in popularity. Critics have argued that these changes amount to exposure misclassification and led to biased results.
Wisner prodded Bello to acknowledge this problematic aspect of the study, but she did not budge.
“Do you have any criticisms of this study?” Wisner asked.
“I actually don’t,” Bello said. “I think they did a great job.”