PARP8 and B-cell chronic lymphocytic leukemia: Compared with normal DM B cells, DM CLL cells exhibited substantially increased R-loops across all genes tested (Akt3, Drosha, Ddx17, Prkce, Parp8, Pouf5l), as well as in positive R-loop–forming regions (Snord116, ref. 40; and c-Myc, ref. 41), while no signal in all samples was detected over the negative control (Snrpn, ref. 40) and under RNH1 treatment (Figure 8F).