TRANSPLANTATION OF 3 TUMORS INDUCED IN RATS BY DIMETHYLNITROSAMINE

Three renal tumors induced in rats by dimethylnitrosamine were serially transplanted in animals of the same strain and one of these tumors was further studied in tissue culture. Originally, these tumors exhibited the histologic characteristics of two different types of stromal nephromas. Their growth rate tended to increase with the number of passages and the percentage of takes was higher in males than in females. In the course of successive passages, the three tumors retained their sarcomatous aspect and either remained undifferentiated or underwent progressive differentiation into primitive mesenchyme, into smooth or striated muscle tissue. The epithelial component of one of these tumors persisted until the third passage; it was well delimited from the surrounding sarcomatoid tissue so that the possibility of a metaplastic transformation seems unlikely. It appears that the transplantation of these neoplasms resulted in a simplification of their structural organization and that they evolved towards a mesenchymal differentiation of the muscular type. Copyright © 1969 Wiley‐Liss, Inc., A Wiley Company