Beta-amyloid precursor protein accumulates in axons around hematogenous metastases of the human brain: immunohistochemical observations.

Axonal changes which develop around hematogenous metastases of the human brain were studied by immunohistochemistry using a monoclonal antibody to beta-amyloid precursor protein (beta APP) and the ABC method combined with glucose-glucose oxidase technique and nickel enhancement. The metastases were obtained from 18 autopsy cases with pulmonary carcinomas and 6 control cases without clinical history or gross pathology of brain diseases. beta APP immunoreactive material was present in distended axons around all the investigated metastases. Such immunoreactive axons were located close to the invading tumor cells. No immunoreactivity was seen in 5 of the 6 controls. Our investigation indicates that axonal transport is disturbed around metastases, made visible by the accumulation of beta APP immunoreactive material. The axonal dysfunction may well influence the clinical symptoms in cases with brain metastases.