Correlation between tumorigenicity and banding pattern of chromosome 15 in murine T-cell leukemia cells and hybrids of normal and malignant cells.

The most common chromosomal aberration in murine T-cell lymphomas is trisomy of chromosome 15. It has now been shown that the chromosomal region 15E exhibits a variant early replication banding pattern after 5-bromo-deoxyuridine labeling during part of the preceding S-phase. This variation is restricted to T-cell tumors. Plasmacytomas bearing the specific translocation t(12;15) show a normal early replication banding pattern of chromosome 15. In T-cell tumors all three chromosomes 15 of one cell are of the same variant banding type. In hybrids between tumor and nontumor cells, the number of cells expressing the variant early replication banding pattern is related to the degree of malignancy. Chromosomes 15 in one cell never expressed the variant and the normal banding pattern simultaneously. All five to six chromosomes 15 from one hybrid cell are of the same banding type irrespective of their parental origin. With respect to the type of early replication banding pattern, there is complete reversibility; tumor-parent-derived chromosomes 15 change to normal, and normal-parent-derived chromosomes 15 change to tumor.