Abstract PO3-19-02: White Button Mushroom and Biomarkers of Immune Cell and Inflammatory Responses in Obese Postmenopausal Women at High Risk of Breast Cancer
Authors: Dzubnar Jessica , Yee Lisa , Chen Shiuan 
Published: May 2024

Abstract
Background:
White Button Mushroom (WBM), Agaricus bisporus, has anti-tumor and anti-inflammatory effects. Oral WBM mitigated the effects of a high fat diet on hepatic steatosis and insulin resistance in ovariectomized mice. A Phase I trial of WBM in men with prostate cancer demonstrated decreased myeloid derived suppressor cells (MDSC) in those with decreased PSA; MDSC have been linked to different cancers, including breast, and conditions of chronic inflammation.
Design:
This is a preliminary evidence trail in postmenopausal, obese women at high risk of breast cancer with a single intervention arm of 14g of WBM taken as 28 tablets daily for 3 months to assess effects on inflammation.
Participants undergo a physical exam, measuring height, weight, and waist circumference, an optional fine needle aspiration (FNA) of breast tissue, a blood draw, a food frequency questionnaire and a 24-hour food recall at baseline and final visits. Participants are contacted monthly for tolerance and adherence.
Blood samples and FNA adipose are used for metabolic measurements and processed for biomarkers of inflammation and immune response. Peripheral blood mononuclear cells (PBMC) will be used for RNA single-cell analysis to assess for immune cell profiles and expression with an interest in evaluating MDSC. Red blood cells will be assessed for fatty acid profiles.
Eligibility:
Postmenopausal, obese (BMI ≥30, Asian ≥25) women with high risk for breast cancer who can swallow pills are eligible. Patients are high risk if their relative risk of breast cancer is ≥2 times that of the general population; this includes women with a strong family history, a genetic mutation associated with hereditary breast cancer, a high-risk breast histology, Gail model 5-year risk &gt;1.67, or a previous history of stage I-II breast cancer.
Participants are excluded for an active malignancy within 5 years, ongoing active or preventative cancer treatment, or lab abnormalities of serum creatinine and total bilirubin &gt;1.5 the upper limit of normal, hemoglobin of &lt; 9.0 g/dL, platelets of &lt; 100,000/mm3, or a total white blood cell count of &lt; 3,500/mm3. Participants cannot be taking mushroom supplements, immunosuppressants, or non-steroidal anti-inflammatories.
Specific Aims:
This study aims to evaluate the effects of WBM on regulating immune response and inflammation in obese women at high risk for breast cancer. Our primary objective is the assessment of PBMC, specifically MDSC immune profiles before and after treatment. Our secondary objective is to evaluate changes in biomarkers of inflammation, immune cell profiles in breast adipose tissue, BMI, waist circumference, and metabolic biomarkers. Additionally, the study aims to assess tolerability of the WBM dose and effects on diet quality.
Statistical Methods:
26 patients will provide 80% power to detect a change in %MDSC of -0.67, assuming a standard deviation of 1.15, and a 2-sided type I error of 5%. We will have similar power to evaluate changes in other immune subsets, inflammatory markers, metabolic markers, anthropometric measurements, and diet quality.
FNA adipose tissue analysis will be used as a safety signal to evaluate the potential for unwanted inflammation with taking WBM. 13 patients with FNA will provide 80% power to detect a change of 85% of the standard deviation of the difference in the measure of biomarkers such as Interleukin-6 with a 2-sided type I error of 5%. As a safety signal, the signal will be reported without adjustment for multiple comparisons. Any conclusions based on such secondary endpoints will make note of the multiple comparison issue.
Accrual:
The accrual target is 26 evaluable patients with an estimated need to enroll 31. The study has enrolled 27 patients, 14 completed the study and 5 are currently on treatment. 8 participants were removed; 3 never started treatment, 1 was diagnosed with breast cancer, and 4 had other medical issues preventing continuation.
Contact: Jessica Dzubnar, MD: jdzubnar@coh.org
Citation Format: Jessica Dzubnar, Lisa Yee, Shiuan Chen. White Button Mushroom and Biomarkers of Immune Cell and Inflammatory Responses in Obese Postmenopausal Women at High Risk of Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-19-02.