ATR and diffuse large B-cell lymphoma: Next, to explore the potential impact of ATR inhibition on immune cell recruitment, we performed a competitive microfluidic assay (42, 43), coculturing peripheral blood mononuclear cells (PBMCs) from healthy donors with ATRi- or DMSO-treated HT and SUDHL-5 DZ-like DLBCL cells (Figure 5F).