To determine whether the increased activity of the Alt-NHEJ pathway in MM cells could be responsible for the higher frequency of NHEJ detected in the plasmid reactivation assays (Fig. 6D), we tested the effect of classical NHEJ inhibition, by the use of the specific DNA-PK inhibitor NU7026, on the efficiency of NHEJ in U266, MM1S, JJN3 and LINF control cells. Here, PRKDC is linked to Miyoshi myopathy.