CHROMOSOMAL CONSTITUTION OF MENINGIOMAS

Benign tumors other than meningiomas usually have either a normal diploid chromosome complement or a non-systematic loss or gain of chromosomes which varies from cell to cell, with a tendency to hyper-ploidy. Most of the meningiomas studied were a mosaic of normal and abnormal cells. The abnormal cell strain was hypoploid and homogeneous in 1 tumor. This homogeneity suggests that these cells had a common origin. The basic chromosome aberration is the loss of a small acrocentric chromosome, accompanied in 4 out of 8 tumors by further numerical aberrations. There were no essential structural abnormalities in any chromosomes.