Variability of 11q23 rearrangements in hematopoietic cell lines identified with fluorescence in situ hybridization

Abstract

We mapped and ordered 17 cosmid, phage, and plasmid clones to chromosome 11, bands q22-q24, using fluores-cence in situ hybridization (FISH). We then analyzed four hematopoietic cell lines with 11 q23 rearrangements, Karpas 45, SUP-T13, RC-K8, and Karpas 422, using these probes. The studies showed that the translocation break-points of the Karpas 45 and SUP-T13 cell lines, which were derived from T-cell malignancies, were located in the same breakpoint cluster region of the MLL gene as the RS4; 11 cell line and patients with the t(9; 11), t(11; 19), and t(6; 11) described previously. We confirmed that the translocation breakpoint of the RC-K8 cell line was located telomeric to the MLL gene, and found that the derivative 11 chromosome of the Karpas 422 cell line, which had been thought to contain a t(4; 11) (q21;q23), was in fact formed through a deletion and an inverted tandem repeat of part of 11 q. © 1993 by The American Society of Hematology.