Karyotype analysis of a human mammary sarcoma explant in vitro.

Karyotype of a fibroblastic SH-1 cell line derived from a human mammary sarcoma had 86 (80-92) chromosomes including 6 (4-7) markers, and a various number of double minutes. There were generally even numbers (e.g., 2, 4, etc.) of chromosomes in 17 intact and 3 common marker chromosomes. The t(3;14) and del(14), which had 2 each per s cell genome, were probably formed by the balanced translocation between nos. 3 and 14. Three other markers were single and contained a partial or entire no. 1. The presence of these latter markers was often accompanied by the decrease in the number of the intact no. 1, indicating that no. 1 was the only chromosome actively engaged in rearrangements during this stage of karyotypic diversification. Of the no. 2 and 7q that were over-represented on the per cell level, the 7q had a similar observation from many other solid tumors found in this and other laboratories. In contrast, none of the under-represented chromosomes had the concordant changes consistent to other tumors, although the frequent involvement of no. 9 in the chromosome rearrangements was seen in some human heteroploidies.