Detection of bcr/abl fusion gene by dual color-dual fusion fluorescence in situ hybridization / 中国实验血液学杂志

This study was aimed to investigate the sensitivity and clinical application of interphase-dual-color and dual-fusion fluorescence in situ hybridization (DC-DF-FISH). The bcr/abl fusion gene was detected by FISH with dual-color and dual-fusion bcr/abl DNA probe in interphase cells of bone marrow from 1295 specimens. Retrospective analysis for the cases was performed by the means of conventional cytogenetic analysis (CCA) and FISH. The results indicated that in 1295 specimens from 539 patients, 456 specimens were positive involved in 310 patients, the karyotypes of 18 patients were normal, 5 patients failed to karyotyping analysis. About 75.5% (234/310) of positive patients displayed the typical DC-DF-FISH signal pattern, 76 patients showed atypical DC-DF-FISH signal patterns, 66 cases out of which showed variant signal, 16 patients displayed typical variant signals (1Y2G2R), 50 patients displayed deletion ABL and/or BCR signal. In 213 patients, the negative rate was 60% (128/213) after the treatment, 12 patients were sometimes negative and sometimes positive during the process of the treatment. It is concluded that DC-DF-FISH can be used to detect karyotypes with masked or variant Ph, gene deletion and minor residual disease (MRD) in process of treatment. The dual-color FISH technique is a much more sensitive and accurate tool for monitoring MRD and monitoring relapse, which is a necessary supplement to CCA.

A comparative cytogenetic analysis in large scale between adult and childhood patients with acute lymphoblastic leukemia / 中国实验血液学杂志

This study was purposed to comparatively analyze the cytogenetic characteristics between 566 cases of adult acute lymphoblastic leukemia (aALL) and 586 cases of childhood acute lymphoblastic leukemia (cALL). The cytogenetic analysis of all the patients was performed, and the FISH detection for partial patients was carried out. The result showed that the difference of chromosome abnormality between cALL and aALL was statistically significant. The percentage of abnormal karyotypes in aALL was 62.0%, including mainly t(9;22)(q34;q11), hypodiploidy, hyperdiploidy (47 - 50), abn(6q), abn(9p) and -7, most of which conferring an unfavorable prognosis. The percentage of abnormal karyotypes in cALL was 39.2%, composed mainly of high hyperdiploidy, hypodiploidy, TEL/AML1(+), +8, hyperdiploidy (47 - 50) and +21, etc, most of which conferring a favorable prognosis. The incidences of abnormal karyotypes, total hypodiploidy, total hyperdiploidy (47 - 50), t(9;22)(q34;q11), -7, abn(7q), abn(14q32) and +Ph in aALL were significantly higher than those of cALL (p < 0.05), whereas the incidences of normal karyotype (N), high hyperdiploidy, +8, +21*2 and TEL/AML1(+) in cALL were significantly higher than those of aALL (p < 0.05). 20.5% of aALL were Ph+ aALL, with 63.8% of which being with additional abnormalities, composed mainly of +Ph, -7, i (9q+), 9p-, +8, +21, +X, 6q-, abn(14q32) and +14. In contrast, only 4.4% of cALL were Ph+ aALL, with 42.3% of which being with additional abnormalities, including mainly abn(9p), abn(7p), -7, 17p- and +21. It is concluded that almost every chromosome is involved in the numerical and structural abnormalities and complex karyotypes are common. The significant difference of chromosome abnormality exists between aALL and cALL.

Clinical and laboratory study of a complex translocation t (6; 21; 8) (p22; q22; q22) in two patients with acute myeloid leukemia / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the clinical and laboratory characteristics of a complex translocation t (6; 21; 8) (p22; q22; q22) in two patients with acute myeloid leukemia.</p><p><b>METHODS</b>Bone marrow (BM) samples were collected at presentation, prepared by short-term (24 hours) unstimulated culture and R-binding, for conventional cytogenetic assay (CCA). The complex translocation was assayed by fluorescence in situ hybridization (FISH) with a dual-color AML1/ETO-specific probe. AML1/ETO chimeric transcript was detected by reverse transcription polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>In both cases CCA demonstrated a complex translocation, t (6; 8; 21) (p22; q22; q22), which was confirmed by interphase and metaphase FISH and AML1/ETO fusion transcript was detected by RT-PCR. Both the two patients were diagnosed as AML-M(2), but with different immunophenotype and therapeutic outcome.</p><p><b>CONCLUSION</b>The t (6; 21; 8) (p22; q22; q22) is a rare variant of complex translocation of t (8; 21) (q22; q22). More such cases are needed for elucidating its clinical features and prognosis.</p>

Conventional cytogenetics and fluorescence in situ hybridization as methods for detecting MLL gene rearrangements in leukemia / 中国实验血液学杂志

This study was aimed to compare the values of conventional cytogenetics (CC), interphase FISH and sequential R-banding and FISH analysis as methods for detecting MLL gene rearrangements. 37 acute leukemia patients were studied by CC and interphase FISH. The results showed that among them, 10 cases were 11q23(+)/MLL(+), 2 cases were 11q23(-)/MLL(+) (5.4%), 3 cases were 111q23(+)/MLL(-) (8.1%) and 22 cases were 11q23(-)/MLL(-). For some patients, different results were obtained by using CC and interphase FISH for detecting 11q23/MLL gene rearrangements. After sequential R-banding and FISH analysis for 6 patients, the chromosome related to MLL gene translocation was seen clearly in karyotypes and FISH image. It is concluded that for accurate diagnosis both CC and FISH are needed for detecting 11q23/MLL gene rearrangements, and evaluation is needed in combination of these two results. When necessary, it needs to do sequential R-banding and FISH or molecular analysis.