NPM1 and Parkinson disease: Whether decreased NPM1-immunoreactive nucleoli in advanced stages of PD was a reflection of the co-occurrence of Lewy bodies in a particular neuron was assessed using double-labelling immunofluorescence and confocal microscopy with anti-NPM1 and anti-α-synuclein antibodies in six cases (1 tissue section per case) of PD at stages 4–5.