A recent publication caught my eye where a study was done with mouse models of and human patients with prostate cancer.
In the mouse models, the addition of white button mushroom (WBM) extract to the diet resulted in reduction in the number of myeloid-derived suppressor cells (MDSC) which promoted antitumor immune responses mediated by T cells and natural killer (NK) cells.  They also observed increased anticancer activity of PD-1 antibodies
In patients a decline was observed in the circulating MDSCs and increase in cytotoxic CD8+ T and NK cells.  The City of Hope is recruiting for a phase 2 trial to further examine the effect of WBM on prostate cancer.
MDSCs are also  emerging target for bladder cancer.   They contribute to the ability of tumors to evade immune detection.  More research, such as that being pursied for prostate cancer, is needed to demonstrate the effect of reducing MDSCs in bladder cancer patients - however, the mechanism is the same for both.
White button mushrooms offer a number of health benefits  (including gut biome health and glucose control which I have mentioned elsewhere are of interest to me) and WBM extract is available as a supplement.
My single treatment for muscle invasive bladder cancer at the moment is pembrolizumab - an immune checkpoint inhibitor.  I've discussed with my oncologist and I am going to taking a daily dose of WBM extract to potentially enhance its effect.  I will start with dose recommended on the product I ordered (500 mg - roughly 1/4 teaspoon daily). I may adjust as I learn more of the dose used in clinical trials.  As always, with any change in diet or medication, you should consult with your care team.

1 year and 6 days ago I had my first PET/CT scan .  [I've mentioned that I led software development for the first generation of PET/CT systems - but this was my first image as a patient.]  That scan showed locoregional spread of my muscle invasive bladder cancer (MIBC) to nearby lymph nodes and changed the standard of care options - and the options would change again 35 days later with the FDA approval of enfortumab vedotin + pembrolizumab (EV/pembo - Padcev/Keytruda) as a first line option for locally advanced and metastatic MIBC.
The performance in the phase 3 clinical trial (EV 302) that lead to approval was impressive - overall response rate of 67.7% and complete response rate of 29.1%.  Testing was done looking at Nectin 4 expression (which enfortumab vedotin targets) and PD-L1 (which pembrolizmab targets) and both high and low groups showed had benefits in progression free and overall survival - therefore, no testing is required to begin EV/pembro treatment for locally advanced and metastatic MIBC.
As I was seeing a good response - I was still curous if there were any explanation (beyond the power of prayer and God's grace) as to why.  I requested a genetic analyis and received the report from a sample of my tumor resected 217 days earier.
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The report showed that I had a combined positive score (CPS) of 10 - which according to one study shows that I was likely to receive benefit from pembrolizumab. My tumor did not have FGFR mutations for which an FGFR inhibitor such as erdafitinib would be effective.
A Nectin-4 histology score (H-score) could evalute its expression in my tumor cells.  However, another study showed that a more common blood marker - C-reactive protein to albumin ratio (CAR) - can predict objective response to EV.

The results showed that lower CAR is associated with a better response.  I am familiar with C-reactive protein (CRP) from a previous health journey (see earlier in the blog) where I lost 100 lbs and reversed type 2 diabetes.  CRP is an indicator of inflammation - which is associated with type 2 diabetes.  It may be that maintaing my weight, exercising and maintaining a low carb real food diet (including healthy fats and proteins) has resulted in a CAR <1 and contributed to a good response to EV.  My lab work before each infusion includes an albumin measurement - I will ask to see if CRP can be measured as well to see if my CAR is below 1.