Abstract
The present study deals with the development of a new subline in a rat ascites tumor, MTK-sarcoma II, with special remarks on the difference of chromosome pattern in the new and original stemline cells. The behavior and history of the two stem cells were also studied in serial transfers and under some experimental conditions.
The new subline is characterized by the tumor cells which are provided with originally occurring two remarkably large median chromosomes and one large submedian chromosome. The data based on the idiogram analysis suggest that the latter chromosome would probably be produced as a result of pericentric inversion in one of the larger chromosomes occurring in the original stem-cell.
After transplantation of a metastatic invasion, the alteration in frequency of the two types of stem-cells occurred with a maintenance of the stemlines. The original stem-cells characterized by two large median chromosomes made their appearance together with the new stem-cells at a very low frequency for a long period through serial transfers, and they were lost from vision in the sample from the 646th transfer generation. The original stem-cells were isolated however in a single cell clone.
