It is a fact that the mortality rate from prostate cancer is higher for black men, yet black men do have greater survival benefits from immunotherapy treatment, specifically to Provenge. Why is this the case?
A study from Northwestern Medicine might have discovered the reason.
Black men often have a higher level of a type of immune cell called plasma cells in their tumors than do white men. These cells might drive a better response to immunotherapy. If this is confirmed, these findings could lead to immune-based precision medicine treatment for men of all races with localized aggressive and advanced prostate cancer.
This research was led by Dr. Edward Schaeffer, chair of urology at Northwestern University Feinberg School of Medicine and Northwestern Medicine. His study found this increase in plasma cells correlated with improved cancer survival following surgery and identify plasma cells as potential drivers of prostate cancer immune-responsiveness.
The study was published on Feb. 10 in Nature Communications.
"If a man's prostate cancer has numerous plasma cells, we found he had improved cancer survival," Schaeffer said. "Our study suggests plasma cells are important in the body's response to cancer."
Although recent research suggests Black men with advanced prostate cancer have improved survival outcomes with immunotherapy, there has been no way to predict which individual patient -- Black or white may respond best to immunotherapy drugs. Schaeffer's team explored this by analyzing the genomics of 1,300 tumor samples annotated with self-identified race or genetic ancestry. They found, on average, more plasma cells in Black men's tumors than white men's.
The finding was not unique to Black men, and the work showed that there was improved cancer-free survival following surgery in all men with elevated plasma cell levels.
"The finding comes at a time as researchers are discovering plasma cells may play a greater role in cancer immunotherapy than previously thought," said first author Dr. Adam Weiner, a Northwestern Medicine urology resident. "Testing for plasma cells in prostate cancer may help identify men who will benefit from immune-based treatments."
Identification and characterization of effective therapeutic targets is a significant and unmet need to improve clinical outcomes and reduce mortality from lethal prostate cancer among African American men.
The immediate take home from this study is that men, black and white, who have higher levels of plasma cells in their tumors should discuss with their doctors, including immune therapy, including Provenge, in their treatment protocols.
The research was supported by the Polsky Urologic Cancer Institute, grant 5U01CA196390 from National Cancer Institute of the National Institutes of Health, the Prostate Cancer Foundation, the 2019 Urology Care Foundation Residency Research Award Program and the Russell Scott, Jr., MD Urology Research Fund.
https://www.nature.com/articles/s41467-021-21245-w
