Karyology of Rhabdomyosarcomas Induced with 3-Methylcholanthrene

Abstract

This work aims to find out how a neoplastic condition affects the chromosome set of the rat. Malignant tumors were induced by 3-methylcholanthrene in adult rats. The karyologic examination of 3 sarcomas (S1, S2, S3) showed that: in S1 65% of the metaphases are hypotetraploid; in S2 75% of the metaphases are roughly diploid and only 25 % are hypotetraploid; in S3 most of the mitoses are hypotetraploid with a circaoctoploid component. It has been observed that the number of chromosome breakages and translocations increases as the chromosome number increases; further, chromosomes not belonging to the normal karyogram of the rat may appear. The karyologic aberrations of the sarcomas were more or less proportional to the degree of histological differentiation of the cellular strain. The appearance of the new chromosomes was correlated with the onset of the tumor.