Mushroom supplement may slow prostate cancer progression
Key takeaways:
- Tablets made from common white button mushrooms may delay prostate cancer progression.
- Researchers also are evaluating the approach for women who have a high risk for breast cancer.
White button mushrooms promoted antitumor activity among men with prostate cancer, according to results of an ongoing randomized phase 2 trial.
Treatment with white button mushroom tablets reduced immunosuppressive myeloid-derived suppressor cells (MDSCs), and it also increased cytotoxic T cells and natural killer (NK) cells.
“Before I joined this study, as a trained pathologist, I didn’t take [this theory] seriously,” lead author Xiaoqiang Wang, MD, PhD, MB(ASCP), staff scientist at Beckman Research Institute of City of Hope, told Healio. “[Mushrooms can] reprogram the anti-tumor immunity and, therefore, contribute to the cancer immune therapy.”
Background and methods
Wang and colleagues — including senior author Shiuan Chen, PhD, chair in biology at Beckman Research Institute of City of Hope — previously conducted a phase 1 trial that showed white button mushroom tablets could decrease PSA.
They also discovered patients had a decrease in MDSCs.
Increased number of polymorphonuclear MDSCs are associated with tumor growth and poor prognosis for men with prostate cancer. MDSCs can inhibit T cells and NK cells’ tumor killing activity.
Researchers further evaluated white button mushroom tablets in mouse models and a small cohort of men from ongoing phase 2 trial with prostate cancer undergoing active surveillance.
The investigational study included 10 men who received the treatment, and eight others who did not.
Researchers collected blood samples at baseline and 3 months into treatment, conducting an unbiased single immune cell sequencing analysis. This approach enables the researchers to examine the individual immune cell responses to mushroom treatment.
They derived a single white button mushroom tablet from 6 g of fresh mushrooms. Patients in clinical trial consumed between 16 to 28 tables per day. “Imagine a basket from Costco (24 ounces),” Wang said. “Patient consumed one-quarter (6 ounces) or one-third (8 ounces) of a basket of those mushrooms each day.”
“We recommended they take them in the morning, afternoon and at evening after meals. Each time they [should] should swallow 10 pills maximum,” Wang said. “That’s our recommendation, but some patients would like to take them all at once.”
Immune responses to white button mushroom tablets served as the primary endpoint.
Results
In mouse models, researchers observed white button mushroom tablets “significantly suppressed” tumor growth and extended survival.
In the phase 2 trial, men who took mushroom tablets exhibited a decrease in circulating polymorphonuclear MDSCs. The control group had no decrease.
The reduction in polymorphonuclear MDSCs caused activation of CD8-positive T cells.
Additionally, they “increased the proportion of PD-1 and CTLA-4 double-positive CD4-positive T cells,” as well as the total number of NK cells, researchers wrote.
“Among the major cell types, neutrophils, monocytes, CD4-positive T cells, CD8-positive T cells, and NK cells were treatment-responsive. These findings provide a scientific foundation for developing mushroom-based products as a promising addition to the future of immunotherapy,” they added.
Wang described adverse events as “very limited,” with digestive discomfort being the only complaint.
“I was really excited about this,” Wang said. “This really is a biological response to the mushroom treatment.”
‘Fun journey’
Wang and colleagues have started analyzing samples collected a year after treatment initiation.
They are looking for any histologic or gene expression changes.
“That will give us direct evidence to prove that mushrooms can really do something on this prostate cancer tissue,” Wang said. “That’s what we’re going to do in the coming year. We’re going to try to finish all this sample analysis, and then also look at all this clinical response from patients.”
White button mushrooms would not replace traditional therapies. Instead, they could be an adjuvant treatment for men with biochemical recurrent prostate cancer or those undergoing active surveillance.
“The cancer they have is low risk and low grade, and it grows very slowly,” Wang said. “They may take many years just to reach a next level of the cancer. If we give them harsh treatment, like surgery or radiologic therapy, they will have to live with side effects for many years. Those patients are looking for any alternative to possibly slow down the tumor progression or control the tumor growth. Our clinical trial for mushroom treatment targets those categories of patients.”
Researchers also plan to evaluate white button mushrooms for other solid tumors.
An ongoing, phase 1 prevention trial investigating the treatment for women who have a high risk for breast cancer.
“Mushrooms have anti-aromatase activity. Aromatase is the enzyme response to produce estrogen, and we know estrogen promotes [initial progression] of breast cancer,” Wang said. “In that way, breast cancer growth or progression could be controlled. That’s the scientific concept behind this.”
Wang and colleagues are investigating other “food as medicine,” as well, including grape seed extract, pomegranate, blueberries and coffee berries.
“It’s a fun journey,” Wang said. “We always hear that you are what you eat. If you eat healthy food, organic food, your bodies use all these nutrients to build up. Let’s try to reprogram our system with healthy food or with this function of food, and [aid] physiologic function or immune function.”
For more information:
Xiaoqiang Wang, MD, PhD, MB(ASCP), can be reached at xiaoqiwang@coh.org.
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