TEL and KIP1 define the smallest region of deletions on 12p13 in hematopoietic malignancies

Unbalanced translocations as well as interstitial deletions of the short arm of chromosome 12 [del(12p)] are found as recurring chromosomal changes in a broad spectrum of hematopoietic malignancies. These changes result in the hemizygous deletion of genetic material from 12p. We mapped a yeast artificial chromosome containing the TEL gene, a cosmid contig containing part of TEL and a P1 contig containing the KIP1 gene to 12p13. These probes were used for fluorescence in situ hybridization to analyze samples from 47 patients with various hematologic malignancies who had unbalanced translocations (25 patients) leading to loss of 12p or deletions (22 patients) involving 12p13. The patients had acute lymphoblastic leukemia (8 cases), myelodysplastic syndrome (MDS; 11 cases), acute myeloid leukemia (AML; 10 cases), myeloproliferative disorders (4 cases), therapy-related MDS or AML (7 cases), non-Hodgkin's lymphoma (2 cases), and other hematopoietic malignancies (5 cases). All three probes were hemizygously detected in 26 cases and were completely retained in only 9 cases. In 12 cases probes for one of the two genes were deleted, allowing us to map the smallest region of overlap of these deletions to a small genomic region that is bordered on the telomeric side by the TEL gene and on the centromeric side by KIP1. The genomic distance between TEL and KIP1 is estimated to be about 1 to 2 Mbp.