Cancer Immunol Res. 2026 Mar 4. doi: 10.1158/2326-6066.CIR-25-0950. Online ahead of print.
ABSTRACT
Merkel cell carcinomas (MCC) typically arise from clonal integration of the Merkel cell polyomavirus. Immunogenic viral oncoproteins then lead to tumorigenesis. Oncoprotein-specific T cells are essential for anti-MCC immunity, but it is unclear whether B cells promote tumor control. Here, we analyzed the frequency and phenotype of viral oncoprotein-specific and total B cells in blood samples from 47 patients with MCC and tumor samples from another 19 patients with MCC. The phenotype of blood B cells did not correlate with MCC patient outcomes. In contrast, all 11 patients with robust oncoprotein-specific antibody-secreting and/or germinal center B cells in tumors experienced long-term MCC control. In vitro, B cells engineered to be specific for viral oncoproteins increased the sensitivity of oncoprotein-specific CD4+ T cells by over 50-fold. Together, our findings suggest that cancer-specific B cells promote antitumor immunity via increased responses by T cells and that cancer-specific augmentation of B cells could be therapeutically relevant.
PMID:41779832 | DOI:10.1158/2326-6066.CIR-25-0950