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Objective: To report clinical and laboratory features of 4 cases of myeloid neoplasm with t (5;12) (q33;p13)., Methods: Cytogenetic examination of bone marrow cells obtained from patients was performed by 24 h culture method. R banding technical was used for karyotype analysis. PDGFRβ gene rearrangement was detected by FISH using dual color break apart PDGFRβ probe. ETV6-PDGFRβ fusion genes were detected by multiple-reverse transcription polymerase chain reaction (RT-PCR). Direct sequencing analysis was performed on the PCR products in case 1. Immunophenotype analysis was carried out by flow cytometry. Four cases were treated with imatinib (IM) and followed up., Results: The diagnoses included 3 MPN and 1 AML-M2. The t (5;12) (q33;p13) was a primary abnormality in 3 cases of MPN and a secondary abnormality in 1 case of AML-M2. PDGFRβ gene rearrangement and ETV6-PDGFRβ fusion genes were detected by FISH and multiple-RT-PCR in 4 cases, respectively. The immunophenotypical analysis of leukemia cells showed positive for CD13, CD33 and CD34. Two cases obtained MMR after the treatment of IM, one case complete hematologic and complete cytogenetic response. ETV6-PDGFRβ was negative detected by multiple-RT-PCR after the treatment of IM, but relapsed and died soon in case 4., Conclusions: The t (5;12) myeloid neoplasm was a subtype with unique features. The t (5;12) maybe a primary chromosome abnormality in MPN and a secondary in AML. MPN with t (5;12) could benefit from IM, but not for AML. Dual-FISH was a reliable tool for detecting PDGFRβ rearrangement.

Background and Objectives: Human leukemia cell lines are of great value in leukemia research. Thus far 36 leukemia cell lines carrying the 11q23 translocation and MLL rearrangements, including two cell lines with t(6;11)(q27;q23) and an MLL-AF6 fusion gene have been described. We have established a new monocytic cell line with t(6;11), designated SHI-1, and herein describe its biological characteristics., Design and Methods: Mononuclear cells isolated from the bone marrow of a patient with acute monocytic leukemia (AML-M5b) at relapse were inoculated and passaged by liquid culture. The biological features of the cell line were characterized by morphological assays, flow cytometry, cytogenetic analysis, reverse transcription polymerase chain reaction (RT-PCR), direct sequencing, fluorescence in situ hybridization (FISH), clonogenic culture, quantitative fluorescent PCR, zymography, short tandem repeating sequences-PCR (STR-PCR), multiplex-FISH (M-FISH), and tumorigenic capacity in nude mice., Results: The SHI-1 cell line has been maintained in continuous culture without any external cytokines for three years. The morphology and immunoprofile of the cells show typical features of monocytic lineage. Karyotypic analysis demonstrated a t(6;11)(q27;q23) translocation accompanied by a deletion of 17p, which are the same abnormalities as were seen in the leukemia cells of this patient in relapse. The MLL-AF6 fusion transcript and the loss of one p53 allele were proven by chromosome painting, FISH and RT-PCR analysis in both SHI-1 cells and the primary leukemia cells. A point mutation of ATC-->ACC at codon 195 of exon 6 in another p53 allele was found by direct sequencing of DNA in SHI-1 cells as well as in the primary leukemia cells. Neither Epstein-Barr virus nor mycoplasma was detected in SHI-1 cells. Tumor masses were found in all sixteen mice 9-19 days after subcutaneous injection of SHI-1 cells. DNA fingerprinting confirmed the authenticity of the cell line., Interpretation and Conclusions: SHI-1 is a new monocytic leukemia cell line with the t(6;11) translocation, p53 gene alterations, and high tumorigenicity in nude mice. It could be a valuable tool in the study of leukemogenesis.

Objective: To study the clinical and cytogenetic characteristics of four patients with myelodysplastic syndrome (MDS) and one with acute myeloid leukemia experiencing t (1;7)., Methods: Five patients seen in our hospital from 1992 to 2001 were diagnosed as MDS and acute myelocytic leukemia (AML) according to the French-American-British (FAB) criteria. Chromosomes were prepared using the direct method as well as 24-hour unstimulated cultures of fresh heparinized bone marrow for each subject, while R-banding was used to analyze karyotypes. Dual-color fluorescence in situ hybridization (FISH) using SpectrumRed and SpectrumGreen directly labeled chromosome 1-specific alpha-satellite DNA probe (red) and chromosome 7- specific alpha-satellite DNA probe (green) was performed for three cases., Results: Of the five patients, three had 1;7 translocation due to a long history of exposure to benzene. In three cases, dual-color FISH resulted in three red signals and two green ones, in which one red signal adjoining one green signal in 27.6%, 84% and 18.5% metaphases, respectively., Conclusions: Exposure to benzene may be the cause for Chinese MDS and AML patients with t (1;7) translocation. The result of dual-color FISH convincingly confirmed that the centromere of the derivative chromosome 7p/1q resulting from 1;7 translocation was made up of centromeres from both chromosomes 1 and 7.