Stimulation of tumour-derived PD-1+ Bregs with PD-1 Ligand (PD-L1) and subsequent co-culture with tumour-derived effector memory T cells, resulted in impaired proliferation and production of granzymes and perforin by CD8+ T cells in an IL-10-dependent mechanism, thereby contributing to tumour growth. The gene discussed is CD274; the disease is neoplasm.