Radiosensitivity and metabolic properties of two tumour-types indigenous to the same host. I. A correlation of cellular structure and radiosensitivity.

Abstract

SummaryThe radiosensitivity and metabolic properties of two types of mouse mammary tumours, epithelial (DBAH) and spindle (DBAG), both indigenous to the same host, are under extensive study. The cytological response of these tumours to 500 r, 1000 r and 3000 r is described in this first report. The spindle-tumour cells (DBAG) proved to be more radiosensitive and produced unusually abnormal mitotic figures, unipolar and multipolar. Electro-micrographs of this tumour revealed a paucity of mitochondria and their inferior quality, thereby explaining their extremely low capacity to phosphorylate in comparison with the epithelial tumour (DBAH). It is postulated that the quantity and quality of mitochondria play a significant role in cellular radiosensitivity. Thus the chromosomal imbalance may not be the only factor in cell-death induced by irradiation. This postulate is supported by observations on the tumours herein reported.