pDCs collected from tumours show high expression of immunosuppressive molecules such as the indoleamine-2,3-dioxygenase (IDO) enzyme, programmed death-ligand 1 (PD-L1) [33], IL-10 and FAS ligand [34–36], by which pDCs can induce apoptosis or anergy of activated T cells or their conversion in regulatory T cells (Tregs) (figure 1c) [37,38]. The gene discussed is FAS; the disease is neoplasm.