ATM and diffuse large B-cell lymphoma: In addition, imaging DLBCL cells that had been co-stained with rhodamine-phalloidin (to visualize F-actin at the cell periphery) and DAPI showed that treating DLBCL cells with ATM-3507 concentrations as low as 78 nM or 1.25 μM, depending on the cell line, resulted in increased cell size as well as enlargement of the nucleus (Figure 5A, Supplementary Figure 2).