CEREBRAL BETA-AMYLOID DEPOSITION IN PATIENTS WITH MALIGNANT NEOPLASMS- ITS PREVALENCE WITH AGING AND EFFECTS OF RADIATION-THERAPY ON VASCULAR AMYLOID

We examined immunohistochemically 123 autopsy brains from patients age d between 30 to 59, who died as a result of malignant neoplasms. Using antiserum to amyloid beta protein (A beta), we found that cerebral A beta deposits began in the subjects' fifth decade; its prevalence was 0%, 9.8% and 21.5% in the fourth, fifth and sixth decades, respectivel y. The major form of A beta deposition was diffuse-type plaques, altho ugh one third of the brains with AP deposition showed amyloid angiopat hy. Subpial A beta deposition is frequently associated with amyloid an giopathy. The prevalence of cerebral A beta deposits was about two tim es higher in the patients who had received brain radiation therapy (27 .8%) compared to non-radiated patients (14.8%). Amyloid angiopathy was much more prominent (P < 0.05) with radiation therapy (22.2%) than wi thout (8.0%). We found that cerebral A beta deposition is dependent on aging, even in patients with malignant tumors and at beginning in the ir forties, and that brain radiation therapy is a possible risk factor of A beta deposition, especially in the form of amyloid angiopathy.