PRF1 and neoplasm: Enrichment of TIL-Bregs correlated with higher frequency of Foxp3+Tregs within tumours of DTC patients. Peripheral CD27+ Bregs from DTC patients produced more IL-10 than those from healthy cohort, and inhibited IFN-γ expression by CD4+ T cells, perforin and GrB expression by CD8+ T cells.