Turkey Tail Mushroom for Treating Post-Menopausal Women With HER2-Negative ER-Positive Breast Cancer Undergoing Surgery

The film gives the main points. The full list below is copied from the registry; the study team makes the final decision.

• Age18 Years to no maximum
• SexFemale
• Healthy volunteersNo

You may be able to join if

• Women ≥ 18 years of age
• Histological confirmation of ER+, HER2- breast cancer, newly diagnosed and tissue available for central confirmation of Ki-67 measurement. Subjects are eligible if they have a Ki-67 of ≥10%. Ki-67 will be repeated for patients who have had this done externally.
• Scheduled for definitive breast surgery
• Detectable disease as defined by mammography, breast ultrasound of greater than 5mm in size.
• NOTE: Tumor lesions in a previously irradiated area are not considered measurable disease; Disease that is measurable by physical examination only is not eligible
• Post menopausal as defined by:
• Self-reported last menstrual period greater than 12 months, or
• Bilateral oophorectomy, or
• Follicle stimulating hormone (FSH) >20 mIU/mL, and estradiol level ≤ 20 pg/mL
• Not taking aromatase inhibitor or a selective estrogen receptor modifier
• Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0, 1 or 2 obtained ≤ 90 days prior to registration
• Platelet count ≥ 100,000/mm^3 (obtained ≤ 90 days prior to registration)
• Absolute neutrophil count (ANC) ≥ 1,000/mm^3 (obtained ≤ 90 days prior to registration)
• Hemoglobin ≥ 11 g/dL (obtained ≤ 90 days prior to registration)
• Serum transaminase [alanine aminotransferase (ALT) or aspartate aminotransferase (AST)] ≤ 1.2 x upper limit of normal (ULN) (obtained ≤ 90 days prior to registration)
• Alkaline phosphatase ≤ 1.2 x ULN (obtained ≤ 90 days prior to registration)
• Serum creatinine ≤ 1.2 x ULN (obtained ≤ 90 days prior to registration)
• Provide written informed consent
• Ability to complete the Symptom Experience Diary by themselves or with assistance

You cannot join if

• Ki-67 of <10%
• Current use of any medicinal mushrooms
• Patient with locally advanced cancer who will require neoadjuvant therapy or metastatic cancer
• Currently on systemic chemotherapy
• Concurrent endocrine therapy (selective estrogen receptor modifiers or aromatase inhibitors)
• Allergy to mushrooms
• Co-morbid systemic illnesses or other severe concurrent disease which, in the judgment of the investigator, would make the patient inappropriate for entry into this study or interfere significantly with the proper assessment of safety and toxicity of the prescribed regimens
• Immunocompromised patients
• Patients known to be HIV positive and currently receiving antiretroviral therapy.
• NOTE: Patients known to be HIV positive, but without clinical evidence of an immunocompromised state, are eligible for this trial
• Uncontrolled intercurrent illness including, but not limited to:
• Ongoing or active infection
• Symptomatic congestive heart failure
• Unstable angina pectoris
• Cardiac arrhythmia
• Or psychiatric illness/social situations that would limit compliance with study requirements
• Receiving any other investigational agent which would be considered as a treatment for the primary neoplasm
• Other active malignancy 3 years prior to registration
• EXCEPTIONS: Non-melanotic skin cancer or carcinoma-in-situ of the cervix
• NOTE: If there is a history of prior malignancy, they must not be receiving chemotherapy treatment for their cancer

This is how the treatment is meant to work. Whether it helps, and how safe it is, is what this trial is testing.

Coriolus versicolor extract. An extract derived from the mushroom Coriolus versicolor, containing polysaccharide K (PSK) and polysaccharide-peptide (PSP), with potential immunomodulating and antineoplastic activities. Coriolus versicolor extract has been shown to stimulate the production of lymphocytes and cytokines, such as interferons and interleukins, and may exhibit antioxidant activities. However, the precise mechanism of action(s) of this agent is unknown. NCI Drug Dictionary

Treatments listed in the registry

• Coriolus Versicolor Extract (Drug): Dietary Supplement Given PO
• Questionnaire Administration (Other): Ancillary studies

Na · Single Group · masking: None

As the registry describes them. Requirements to join, such as a tissue sample, are in the eligibility list above even when on-study procedures are optional. Ask the study team which steps apply to you.

• questionnaires: Part of the study plan
• surgery: Part of the study plan

Main goals

• Change in Ki-67 (Baseline; at the time of surgery)

Other goals

• Quality of life changes
• Adverse effects of Turkey Tail Mushrooms (TTM)
• Patient-reported outcomes

Planned enrollment: 40 (estimated).

• Mayo Clinic in Arizona, Scottsdale, Arizona

Site status as of Oct 30, 2026. Check the live record before contacting a site.

• ClinicalTrials.gov NCT06450873
• NCI Drug Dictionary: C78184

Registry record reviewed as fetched Oct 30, 2026, last updated by the sponsor Oct 15, 2026. Public record; not medical advice.