Oestrogen has immunogenic properties, influencing the activity of dendritic cells, macrophages, mast cells, neutrophils, natural killer (NK) cells, B cells, CD4+ T cells, and regulatory T cells (Tregs) (40–42), as well as increasing the protein expression of programmed death ligand 1 (PD-L1) on tumour cells (43). The gene discussed is CD4; the disease is neoplasm.