Conclusion: Consequently, HER2 expression was detected in 43 % of meningiomas. No significant difference was seen between grade I and II/III meningiomas, primary and recurrent tumors, and males and females from the point of view of HER2 expression. Objective: In our previous papers we studied accumulation of iron and proteoglycans in the brain. The aim of this analysis is to build on our previous results alongside other authors to investigate the reason for the presence of excessively accumulated iron observed in Parkinson disease (PD). Method: Postmortem samples taken from the globus pallidus were prepared for light microscopy for iron and proteoglycans detection. Patients had neither iron metabolism disorders nor had clinical signs of neurodegeneration. The samples were analysed using electron paramagnetic resonance (EPR) to investigate the bounds between iron and proteoglycans.