OAKLAND, Calif. (CN) – Alva Pilliod’s lymphoma likely had no known cause, but his singularly abnormal immune system allowed it to flourish, an oncologist testified Monday in the latest trial over whether Monsanto’s top-selling weed killer Roundup causes cancer.
Monsanto wrapped its defense with testimony from Dr. Alexandra Levine, an oncologist with the City of Hope cancer center. Levine said decades of spraying Roundup did not contribute to Alva Pilliod’s illness.
“Based upon the entirety of the data, I feel Roundup did not have anything to do with his development of non-Hodgkin lymphoma,” she told jurors, adding, “His abnormal immune system would have truly allowed this to occur.”
Levine refuted her City of Hope colleague, pathologist Dr. Dennis Weisenburger, who testified earlier in the trial that decades of frequent Roundup use caused both Alva and his wife Alberta to develop cancer within four years of each other.
Levine, who is touted as an “acclaimed expert” on lymphoma, Hodgkin’s disease and AIDS by City of Hope, said in her 50-year career as a doctor she’s never seen anyone so immunosuppressed as Alva Pilliod.
Pilliod, who developed diffuse Large B Cell lymphoma in 2011, also suffers from recurrent brain infections, or encephalitis, brought on by the human papillomavirus. He’s also developed a complicated seizure disorder and meningitis, for which he spent four weeks in a coma, and has had skin cancer 22 times.
While none of these diseases are causes of lymphoma, Levine said they are signs he suffers from an unusually weakened immune system that allows malignant cancer cells to thrive.
“This is not a normal immune system, and I say that based on 50 years of being a doctor who deals with this stuff,” Levine said. “I think his abnormal immune system substantially increased his risk of non-Hodgkin lymphoma. His immune system has been abnormal since at least his 20s.”
Levine testified cancer requires several elements to develop, beginning with a specific, permanent mutation in the DNA that controls how cells divide. While about 90 percent of mutations are benign “passenger mutations” Levine said “don’t really matter,” in some rare cases a mutation will be carried forward and become dangerous.
“The mutation is going to say to that cell, ‘Divide and never stop and don’t die either,’” Levine said.
A person’s body must also have some impairment in its ability to repair the DNA damage, and an immune system that is unable to fight off the cancer cells.
“Really, you need a specific driver mutation, inability to correct that and also an abnormal immune system,” Levine said.
Under questioning from Monsanto attorney Tarek Ismail, Levine testified instances of non-Hodgkin lymphoma have plateaued in the last 20 years even while the use of glyphosate, the main chemical in Roundup, has drastically increased in the United States. She attributed the rise in non-Hodgkin lymphoma in the 1980s to the AIDS epidemic.
“What accounted for the increase turned out to be the AIDS-related lymphomas,” she said. “Around 1996 we developed multi-agent therapy and different drugs to treat HIV. The risk of these lymphomas substantially went down.”
She added: “My understanding is as glyphosate use increased substantially in the United States – and I understand it’s one of the most commonly used substance of its kind – if this really were a major cause of non-Hodgkin lymphoma I would have seen the rate of non-Hodgkin lymphoma go up just as I saw it go up when something new called HIV came up. But I don’t see that.”
Levine also praised the findings of regulatory bodies around the globe – the United States, Japan, Canada, New Zealand and Australia – that glyphosate is not carcinogenic.
“I looked at the reviews, which were very carefully done, and they all come to the conclusion that glyphosate does not cause cancer in humans,” Levine said. “I was impressed with the findings around the world.”
These findings contradict the International Agency for Research on Cancer’s 2015 classification of the herbicide as “probably carcinogenic to humans.”
Levine said she respects the IARC, which includes scientists from the U.S. Environmental Protection Agency, but pointed to part of its monograph that said bacterial mutagenesis tests for glyphosate were negative.
“Glyphosate does not cause mutations, she said. “IARC says it is non-mutagenic, every regulatory agency says it did not cause mutations.”
On cross-examination, the Pilliods’ attorney Michael Miller pointed out the California Environmental Protection Agency has declared Roundup a carcinogen.
“In California, Roundup is a known cause of cancer,” he said.
Levine noted under California’s Proposition 65, anything the IARC lists as probably carcinogenic goes on the state’s list of toxic agents.
Miller also questioned Levine about a recent meta-analysis by University of California, Berkeley, toxicologist Luoping Zhang. Zhang pooled data from several studies and found exposure to glyphosate-based herbicides led to a statistically significant increase in the risk of developing non-Hodgkin lymphoma. Levine’s colleague Weisenburger has testified the Zhang study supported his own conclusion that glyphosate-based herbicides and non-Hodgkin lymphoma are connected.
Levine criticized the analysis for using “older data” and some that was not adjusted for other pesticides. “It’s mixed up. Some of it is adjusted and some not, and it makes it less than what I would want for actual validity,” she said.
Miller also showed Levine a line graph indicating instances of non-Hodgkin lymph have actually increased slightly alongside the popularity of glyphosate. Levine said Miller was fudging the data instead of relying on reports from the National Cancer Institute’s cancer registry.
“You’re trying to make it look a different way,” she said. “I don’t think it’s a fair representation.”
On redirect, Monsanto’s attorney Ismail asked: “Is there any dispute in the lymphoma scientific community that the rate of non-Hodgkin lymphoma has plateaued?”
“There is no question at all,” Levine said.
The case is expected to go to the jury Wednesday.