Plasma Cells and Immune Responsiveness in Black Men With Prostate Cancer
Posted: Tuesday, March 23, 2021
Black men experience high rates of death due to prostate cancer; however, they seem to derive greater survival benefits from immune-based treatment than White men. A study conducted by Edward M. Schaeffer, MD, of the Northwestern University Feinberg School of Medicine, Chicago, and colleagues revealed this may be due to an increase in plasma cells. In an institutional press release, the investigators suggested that it may be possible to identify men with prostate cancer who will benefit from immune-based treatments by testing for plasma cells. Their findings were published in Nature Communications.
“Prostate tumors from Black men or men of African ancestry have increases in plasma cell infiltrate and augmented markers of natural killer cell activity and IgG expression,” the investigators commented. “These findings are associated with improved recurrence-free survival following surgery and nominate plasma cells as drivers of prostate cancer immune responsiveness.”
In this study, the investigators conducted several laboratory assessments to analyze the genomics of more than 1,300 tumor samples from two self-identified race and one genetic ancestry cohort. In a self-identified race cohort, each tumor’s ability to resist lymphocyte infiltration was assessed using an established expression-based signature of tumor lymphocyte evasion.
Tumors with the lowest lymphocyte evasion scores appeared to be significantly enriched among Black men; therefore, these tumors may be more susceptible to lymphocyte infiltration into the tumor microenvironment, the investigators proposed. An assessment of potential effect modifiers revealed that the association between prostate tumors in Black men and increased plasma cell content seemed to be independent of rearrangements in ERG and PTEN loss.
The investigators proposed that plasma cell content may prognosticate outcomes after surgery. In a self-identified race cohort, increasing plasma cell content appeared to be associated with a significantly prolonged duration of metastasis-free survival. Patients in the genetic ancestry cohort who had elevated plasma cell levels seemed to experience a significantly prolonged duration of disease-free survival after surgery.
Disclosure: The study authors reported no conflicts of interest.