PML and frontotemporal dementia: Given that PML-NBs were suggested to participate in the clearance of TDP-43 and FUS [20], we selected for our study brain and spinal cord samples from familial C9orf72 ALS-FTD cases, which are also characterized by TDP-43 pathology [6, 28], and FUS ALS-FTD cases, where FUS pathology was dominant, to explore whether changes at the levels of PML-NBs occurred.