Deng G., Lin H., Seidman A., Fornier M., D'Andrea G., Wesa K., Yeung S., Cunningham-Rundles S., Vickers A.J., Cassileth B. A phase I/II trial of a polysaccharide extract from Grifola frondosa (Maitake mushroom) in breast cancer patients: immunological effects. J Cancer Res Clin Oncol. 2009;135(9):1215–1221.
Rationale
Cancer patients widely take mushroom supplements "for immunity," and maitake's D-fraction is among the most marketed. Yet no human dose-finding data existed — this phase I/II trial was designed to map the dose–response rather than assume it.
Methods
An open-label phase I/II dose-escalation study at Memorial Sloan Kettering: 34 postmenopausal women, disease-free after breast-cancer treatment, received the liquid D-fraction polysaccharide extract at five dose levels — 0.1, 0.5, 1.5, 3 and 5 mg/kg twice daily — for 3 weeks. Immune endpoints included lymphocyte subsets and functional assays; the primary frame was safety plus immunological response by dose.
Results
No dose-limiting toxicity was reached — the extract was safe across the full range. Immune changes were statistically significant (p<0.0005) but non-monotonic: intermediate doses sometimes stimulated and sometimes suppressed the same parameters as higher doses — there was no clean "more = stronger" relationship.
Conclusions
The extract is immunologically active and safe, but its dose–response is complex and bidirectional — a genuinely important negative-style result for a field prone to assuming linearity.
Worth noting
This is the card that most deserves attention from anyone dosing mushroom supplements: an honest demonstration that immunomodulation is not monotonic. Open-label and n=34 across five cohorts means ~7 per dose — the significance is real but the pattern detail is preliminary. Practically: dose selection for immune endpoints cannot be guessed from "bigger is better"; it must be measured.