PML and Hutchinson-Gilford progeria syndrome: Interestingly, we found that PML NBs were aberrantly organized into thread‐like structures in a significant proportion of HGPS cells at late passage, ranging from ~13% to ~28% in four cell lines derived from individual HGPS patients—HG122, HG143, HG155, and HG169 (Figure 1a,b, and Figure S1a,b).