Abstract
The general concept of pathogenesis of nephroblastoma (Wilms's tumor) indicates at present that the origin of the tumor is the metanephric blastema, however, the present electronmicroscopic findings suggest a necessity to suppose a viral factor for carcinogenesis. In this report, the light- and electron-microscopic studies were made on the tissue or cells of nephroblastoma extirpated surgically. The tumor cells revealed light-microscopically the tubular appearance resembling the renal tubules. The nucleus of the epithelial cell of the tubules in question contained both the rod-like structures of 250-350 Å in width and the virus-like particles of the same dimension, the globular particles being otherwise in part arranged in a mode of crystal. There was also the matrix of reticular structures supposed to be precursors of the particles. In addition, the morphological change and feature of the rodlike structure and the particles were correlatively investigated with a distribution pattern of chromatin which may be the functional site of the formation of these structures and is chemically composed of deoxyribonucleic protein. Moerover, the comparative discussion was made between intranuclear virus particles reported so far and the structures resembling the virus particles observable in the nuclei of the normal and cancer cells. The histogenesis of nephroblastoma (Wilms's tumor) was proposed by summarizing these experimental facts and hypothetical concepts.
