| Popis: |
Tumor cells are characterized by high variability and it is possible, as a rule, to isolate from a tumor some stem cell lines with various numbers of chromosomes and with chromosome markers. Studies were carried out on transplantable ascites tumors in mice (NK/Ly, L5178 and Sarcoma 37 strains). Only hypertetraploid cells remained in a nitrosomethylurea-resistant tumor strain. Sarcoma 37 and leukemia L5178 which were also resistant to chemotherapy, differed from the initial sensitive tumors by the presence of new stem cell lines with a definite number of marker chromosomes. It is suggested that the variety of tumor karyotypes within a strain is a result of cell selection in the course of tumor progression. This fact must be taken into consideration by cancer chemotherapy whether by single agents or by combinations. |
