Clinical and molecular cytogenetic studies in ten patients with hematological malignancies characterized by t(20;21)(q11;q11) resulted from del(20q)

This study reports 10 patients with hematological malignances with t(20;21)(q11;q11) resulting from del(20q) (for example, der(20)del(20)(q11q13)t(20;21)(q11;q11) and der(21)t(20;21)(q11;q11)) and described their clinical features and the possible prognostic significance of this abnormality. The t(20;21)(q11;q11) was a rare but recurrent abnormality secondary to del(20q) besides i(20q-). The frequency of der(20)del(20)(q11q13)t(20;21)(q11;q11) among our patients with del(20q) was 2.4%. It was considered that the 20q deletion preceded translocation with chromosome 21. This abnormality is often cryptic, occurs predominantly in older men and is observed most often in myelodysplastic syndromes. Patients with this abnormality have an unfavorable prognosis, similar to patients with i(20q-). The molecular consequences of der(20)del(20)(q11q13)t(20;21)(q11;q11) may be different from patients with i(20q-). To the best of our knowledge this is the largest dataset published to date.

Chronic myeloid leukemia with e14a3 BCR-ABL transcript: analysis of characteristics and prognostic significance

Chronic myeloid leukemia (CML) is characterized by Philadelphia chromosome (Ph) and BCR-ABL fusion genes. This study retrospectively analyzed 2381 CML patients with Ph chromosome confirmed by cytogenetics, Fluorescence in situ hybridization (FISH) or real-time quantitative polymerase chain reaction (Q-PCR). Among them, five CML patients without e13a2, e14a2 or e1a2 transcripts detected by Q-PCR were identified. DNA sequencing confirmed the fusion of BCR exon 14 and ABL exon 3. Case 1 reponded poorly to imatinib and achieved complete cytogenetic response (CCyR) after converting from imatinib to dasatinib. BCR-ABL transcripts were undetectable in cases after 2, 3 and 4 treated with imatinib after 6, 6 and 3 months, respectively, and in one patient who had undergone allogeneic hematopoietic stem cell transplantation after 4 months. Q-PCR may miss the detection of rare cases that are not covered by the primers used in Q-PCR, unless the proper primers are used.

[Clinical and genetics characteristics of patients with monosomal karyotype acute myeloid leukemia patients]

OBJECTIVE

To investigate the clinical and genetics characteristics of patients with monosomal karyotype acute myeloid leukemia (MK-AML).

METHODS

The karyotypes of 3743 patients with newly-diagnosed de novo AML were analyzed, which had identified 153 cases with MK-AML, for whom the clinical and genetics characteristics were analyzed.

RESULTS

There were 2056 patients (54.9%) among all patients. A total of 153 patients fulfilling the criteria for MK-AML were identified, which comprised 93 males and 60 females, with a median age of 54. The median white blood cell count on presentation was 4.4×10 (9)/L. One hundred and forty-five cases (94.8%) have fulfilled the criteria for complex karyotype (≥ 3 chromosomal abnormalities). Although the monosomy could be found with all autosomes, chromosome 7 has been most frequently involved (38.56%, 59/153).

CONCLUSION

MK-AML is a distinct cytogenetic subtype of AML. Monosomy 7 is frequently detected among MK-AML patients. The monosomal karyotype is common among elder patients with AML.

[A clinical and laboratory study of chronic myeloid leukemia with atypical BCR-ABL fusion gene subtypes]

OBJECTIVE

To explore the clinical and laboratory features of chronic myeloid leukemia (CML) with atypical e14a3 and e19a2 BCR-ABL fusion gene subtypes.

METHODS

We retrospectively analyzed a cohort of CML patients with Ph chromosome positive confirmed by cytogenetic and FISH but classical e13a3(b2a2), e14a2(b3a2)and e1a2 fusion transcripts negative identified by conventional real-time quantification RT-PCR (RQ-PCR). Further RQ-PCR was done with the forward primer and reverse primer designed to detect rare atypical BCR-ABL fusion genes including e14a3 and e19a2 transcripts. Direct sequencing analysis was performed on the PCR products and mutations in the BCR-ABL kinase domain were detected. The clinical data of patients were retrospectively analyzed.

RESULTS

Six CML patients were found to carry t(9;22) abnormality and BCR-ABL rearrangement confirmed by FISH but classical BCR-ABL fusion genes negative detected by RQ-PCR. Further RQ-PCR and sequencing analysis confirmed the fusion of BCR exon 14 and ABL exon 3 in five CML patients (case 1-5) and the fusion of BCR exon 19 and ABL exon 2 in one CML patient (case 6). E255K and I293T IM-resistant mutations were detected in case 1 and 2, respectively. Among five cases with e14a3 transcripts, four were CML-CP, one CML-AP. Four patients were male and one was female. The median age was 48 years. The patient (case 6) with e19a2 transcripts was 40-year-old female with a diagnosis of CML-CP and PLT count was more than 1 000×10⁹/L. Imatinib (IM) therapy was administer in case 1, 2, 3, 4 and hematopoietic stem cell transplantation (HSCT) was undergone in case 5 after hydroxyurea (Hu) or interferon failure. Case 1 who had E255K IM resistant mutation, responded poorly to IM but obtained a complete cytogenetic remission (CCyR) after a substitution of dasatinib for IM. Case 2 and 3 achieved CCyR 6 months later after IM treatment and had been maintained well with IM despite I293T mutation in case 2. Case 4 attained CCyR 3 months later after IM treatment but relapsed and died soon. Case 5 was still in CCyR after HSCT. Case 6 with e19a2 transcripts got complete hematologic response after Hu treatment and CCyR was achieved soon after IM therapy.

CONCLUSION

Incidence of CML with atypical transcripts is extremely low. They could benefit from tyrosine kinase inhibitors or HSCT. Rare and atypical BCR- ABL fusion gene subtypes could be missed by conventional RQ-PCR.

Up-regulation of TIMP-2 expression promotes SHI-1 leukemic cells proliferation and infiltration in immunodeficiency mice

BACKGROUND

MMPs and TIMPs play important roles in tumor angiogenesis and invasion. Studies have shown that TIMP-2 has two roles in tumor invasion. However, its role in leukemic infiltration has not been well investigated. This study explored the roles of TIMP-2 in extramedullary infiltration of acute monocytic leukemic SHI-1 cells both in vitro and in vitro.

METHODS

A retroviral vector carrying the human TIMP-2 cDNA was constructed and transfected into the monocytic leukemic cell line SHI-1. The expression of TIMP-2 in the positive clones was determined. The proliferation of SHI-1 cells was examined by MTT assay. Trans-Matrigel invasion assays were used to investigate the infiltration ability in vitro. SHI-1 cells were intravenously injected into pre-treated nu/nu mice to investigate the infiltration ability feature in vitro.

RESULTS

The expression of TIMP-2 on the cell membrane was significantly elevated in SHI-1/TIMP-2 cells. Over-expression of TIMP-2 promoted the cells proliferation and the invasions in vitro. The SHI-1/TIMP-2 cells demonstrated higher infiltration ability when intravenously injected into nu/nu mice.

CONCLUSION

Over-expression of TIMP-2, especially on the cell membrane, may play important roles in promoting the proliferation and infiltration of SHI-1 leukemic cells.

[Immunophenotyping and molecular genetic analysis of diffuse large B-cell lymphoma]

OBJECTIVE

To perform immunophenotyping and molecular genetic analysis for diffuse large B-cell lymphoma (DLBCL), and to explore their correlation and implication for prognosis.

METHODS

Immunohistochemical streptavidin peroxidase (SP) method was used to determine the expression of CD10, BCL6 and MUM1 in 59 cases of DLBCL. A Hans algorithm was used to classify DLBCL into germinal center B-cell (GCB) and non-GCB subtypes. Interphase fluorescence in situ hybridization (FISH) assay was performed on paraffin-embedded lymphoma tissue sections to detect translocations and amplifications of BCL6, BCL2 and MYC genes with dual-color break-apart BCL6 probe, dual-color dual-fusion IgH/ BCL2 probe and dual-color break-apart MYC probe, respectively.

RESULTS

In the 59 cases of DLBCL, 28.8% (17/59) belonged to GCB subtype, and 71.2% (42/59) belonged to non-GCB subtype. The incidences of BCL6, BCL2 and MYC gene translocations were 24.1% (14/58), 1.7% (1/59) and 5.3% (3/57), respectively. The incidences of BCL6, BCL2 and MYC gene amplifications were 17.2% (10/58), 22.0% (13/59) and 21.1% (12/57), respectively. BCL6 amplification was not correlated with BCL6 translocation (P=0.424), but was correlated with amplifications of BCL2 and MYC (C=0.405 and 0.403, respectively, P <0.01). The incidence of BCL6 translocation in GCB type was higher than that in non-GCB type, and amplifications of BCL6, BCL2 or MYC were more frequently encountered in non-GCB type, though no statistical significance was detected (P=0.089 and 0.106, respectively). By univariate analysis, immunophenotyping and international prognostic index (IPI) exerted a significant effect on overall survival (OS) (P=0.047 and 0.001, respectively), but to which BCL6 translocation and amplification of the 3 genes were not related (P=0.150 and 0.444, respectively). By multivariate analysis, IPI score was the only independent prognostic factor for OS (RR =3.843, P=0.017).

CONCLUSION

The GCB subtype of DLBCL is less common in the patient cohort. Common genetic aberrations have included BCL6 translocation and BCL6, BCL2 and MYC amplifications. Amplification of the 3 genes is strongly correlated with each other, and the incidence of BCL2 translocation is low. Immunophenotyping only has minor significance for the prognosis. Genetic aberrations cannot predict the clinical outcome of DLBCL.

[Clinical and laboratory investigation of pericentric inv(9)(p22q34) with the der(9)t(9;22)(q34;q11) in Ph-positive leukemia]

OBJECTIVE

To investigate clinical and molecule genetics features of four Ph-positive leukemia patients characterized by pericentric inv(9)(p22q34) with the der(9)t(9;22)(q34;q11).

METHODS

Cytogenetic analysis was carried out on bone marrow directly or after short-period culture. R banding was used for karyotype analysis. BCR/ABL fusion gene was detected with interphase fluorescence in situ hybridization (FISH), and chromosome painting was carried out using specific probes. RT-PCR was used to detect BCR/ABL chimeric transcripts.

RESULTS

One patient with acute myeloid leukemia (AML) presented three clones, which included one with a normal karyotype, one with t(9;22)(q34;q11), and one with inv(9)(p22q34) involving the der(9)t(9;22) and additional t(8;12)(q12;p11). The inv(9)(p22q34) has always co-occurred with der(9)t(9;22)(q34;q11) accompanied by der(22)t(9;22)(q34;q11) in all metaphases from the three patients with chronic myeloid leukemia (CML). B3a2 transcript was detected in all patients by RT-PCR. Inv(9)(p22q34) was found in both CML and AML, and was associated with poor prognosis.

CONCLUSION

Inv(9)(p22q34) is a novel, rare, but recurrent secondary chromosomal abnormality for Ph-positive leukemia. Leukemia with der(9)t(9;22) and inv(9)(p22q34) has unique clinical and laboratory characteristics.

[Clinical and experimental studies of childhood acute myeloid leukemia with 11q23/MLL rearrangements]

OBJECTIVE

To explore clinical and experimental features of 28 cases of childhood acute myeloid leukemia (AML) with 11q23/MLL gene rearrangements.

METHODS

Karyotypes of 234 cases of de novo childhood AML were analyzed using short-term culture of bone marrow cells and R-banding. The fusion transcripts involving MLL gene and partial tandem duplication of MLL (MLL-PTD) were detected by multiple reverse transcription polymerase chain reaction (RT-PCR) assay. Two cases with 11q23 translocation by karyotypic analysis but with negative result of multiple RT-PCR were studied with MLL-dual-color fluorescence in situ hybridization (D-FISH).

RESULTS

R-banding karyotypic analysis has revealed 20 cases with 11q23 translocation (14 cases with M5, 4 cases with M4, 2 cases with M2), including 12 cases with t(9;11)(p22;q23), 3 cases with t(1;11)(q21;q23), 2 cases with t(6;11)(q27;q23), 1 case with t(11;19)(q23;p13), 1 with t(5;11)(q31;q23), and 1 with t(X;11)(q24;q23). Eighteen cases with 11q23 translocation having fusion transcripts involving MLL genes were confirmed with multiple RT-PCR; 2 cases showed negative results, but they were confirmed to have MLL rearrangements by D-FISH. MLL-PTD was also detected in 8 cases (4 cases M5, 2 cases M4, M2 and M6, one case each) from the other childhood AML cases. The total incidence of 11q23/MLL gene rearrangements was 11.97% (28/234), and most of patients(85.7%, 24/28) were M4/M5. The complete remission (CR) rate after treatment for the 28 cases with MLL rearrangements was 53.8%, the difference was significant by statistics (P< 0.05) compared with 90.5% for the control group (M4/M5 childhood AML with other karyotypic abnormalities or normal karyotype). Of them, 2 cases receiving intensive chemotherapy survived for 81 and 66 months, respectively, 4 cases receiving allogeneic stem cell transplantation survived for 21, 20, 16 and 11 months, respectively, and are still alive with CR. The medium survival (MS) time for 28 cases with 11q23/MLL rearrangements was 11 months, whereas the MS for control group was 15 months. The difference was not statistically significant(P> 0.05).

CONCLUSION

The 11q23/MLL rearrangements is highly correlated with the occurrence of monocytic leukemia (M4 and M5). The 11q23 translocation and MLL-PTD are mutually exclusive, though both are indicative of poor prognosis. Intensive chemotherapy and allogeneic stem cell transplantation may ameliorate the clinical outcome. Multiple RT-PCR combined with karyotypic analysis and D-FISH are useful for screening the 11q23/MLL rearrangements in childhood AML.

[Clinical and laboratory features of pediatric acute myeloid leukemia with inversion of chromosome 16]

OBJECTIVE

To evaluate the clinical and laboratory features of pediatric inv(16) acute myeloid leukemia (AML) retrospectively.

METHOD

Dual color fluorescence in situ hybridization (D-FISH) using a LSI CBFβ inv(16) break apart probe labeled by Spectrum red and Spectrum green was performed in 15 acute myeloid leukemia cases, including 13 cases with or without abnormal eosinophils but with positive core binding factor β (CBFβ)-MYH11 fusion transcript detected by RT-PCR, and 2 cases with trisomy 8 (+8). The results were compared with the morphology, immunophenotype, karyotype and RT-PCR.

RESULT

Morphologically, 12 cases were diagnosed as M(4)EO, 2 as M(4), and 1 as M(2a). Immunophenotypically, all 13 AML cases with inv(16) showed positive expression of CD(13) and CD(33), but without the expression of any lymphoid lineage antigens. Karyotyping analysis with G-banding detected inv(16) in 10 AML cases, including 9 M(4)EO cases and 1 M(2a), but only 5 positive cases were detected using R-banding technique. Among them, 2 cases had simultaneous +8 and trisomy22 (+22), one had +22 only in addition to inv(16). D-FISH revealed a CBFβ-MYH11 rearrangement in 13 cases of AML with positive RT-PCR results, and the mean positive rate of cell detection was 55.15% (range 37.0% - 86.0%). The complete remission rate (CR) and median survival period in this series of inv(16) AML were 81.5%and 11 months, respectively, of whom, 8 cases were still in CR. Relapse and karyotypic evolution were seen in case 5 with +8, +22 in addition to inv(16).

CONCLUSION

AML with inv(16) is a special subtype. Most cases belong to M(4)EO. Its prognosis is good in general, but it seems to be an unfavorable feature for AML with inv(16) and +8, +22 simultaneously, especially with karyotypic evolution. For detection of inv(16), G-banding technique is evidently superior to R-banding technique. D-FISH combined with RT-PCR are more sensitive and reliable than chromosome banding analysis.

[Clinical and experimental study of a multiple myeloma case with low hypodiploidy]

OBJECTIVE

To report the clinical and laboratory characterization of a case of multiple myeloma with low hypodiploid complex karyotyptic abnormalities.

METHODS

Cytogenetic examination of bone marrow performed by 24 h culture method. R-banding technique was used to analyze the karyotype. Interphase fluorescence in situ hybridization (FISH) was performed using chromosome probes such as 13q14, p53, Rb1, 1q21 and IgH/CCND1. The DNA content was detected by flow cytometry.

RESULTS

Chromosome analysis revealed complex chromosomal rearrangement. Five cells had a low hypodiploid karyotype with 35 chromosomes. Three cells had the duplication of the low hypodiploid karyotype. Four cells had a normal karyotype. Monosomy 1, 13, 14, 17 and a mark chromosome 1 derived from chromosome 11 resulting in the amplication of CCND1 gene were confirmed by interphase FISH. Flow cytometric analysis displayed a low hypodiploid peak with the DNA index of 0.8426.

CONCLUSION

These results indicated that the low hypodiploidy is a rare abnormality in multiple myeloma. Interphase FISH is a reliable method for detecting molecular abnormalities in multiple myeloma.

Clinical, immunophenotypic, cytogenetic, and molecular genetic features in 117 adult patients with mixed-phenotype acute leukemia defined by WHO-2008 classification

Among 4,780 consecutive adult acute lymphoblastic/myeloblastic leukemia patients, we identified 117 (2.4%) patients with mixed-phenotype acute leukemia fulfilling WHO 2008 criteria; these were classified as: Blymphoid+ myeloid (n=64), T-lymphoid+myeloid (n=38), B+T-lymphoid (n=14) and trilineage (n=1). Of 92 patients karyotyped, 59 were abnormal and were classified as: complex (22 of 92), t(9;22)(q34;q11) (14 of 92), monosomy 7 (7 of 92), polysomy 21 (7 of 92), t(v;11q23) (4 of 92), t(10;11)(p15;q21) (3 of 92), while STIL-TAL1 fusion was detected in one (T+My) patient. After investigating common acute leukemia-related mutations in 17 genes, 12 of 31 (39%) patients were found to have at least one mutation, classified with: IKZF1 deletion (4 of 31), and EZH2 (3 of 31), ASXL1 (3 of 31), ETV6 (2 of 31), NOTCH1 (1 of 31), and TET2 (1 of 31) mutations. Array-CGH revealed genomic deletions of CDKN2A (4 of 12), IKZF1 (3 of 12), MEF2C (2 of 12), BTG1 (2 of 12), together with BCOR, EBF1, K-RAS, LEF1, MBNL1, PBX3, and RUNX1 (one of 12 each). Our results indicate that mixed-phenotype acute leukemia is a complex entity with heterogeneous clinical, immunophenotypic, cytogenetic, and molecular genetic features.

[Clinical and molecular cytogenetic studies of a case of B-lineage acute lymphoblastic leukemia with t(14;14)(q11;q32)]

OBJECTIVE

To report on a rare case of B-lineage acute lymphoblastic leukemia (B-ALL) with t(14;14) (q11;q32) and clarify its clinical and molecular cytogenetic features.

METHODS

Clinical data of a B-ALL patient with t(14;14) (q11;q32) were analyzed. After 24 hour of unstimulated culturing, chromosome specimens of bone marrow cells were prepared with regular method, and R-banding was used for karyotype analysis. Fluorescence in situ hybridization (FISH) analysis was performed on fixed bone marrow cells using IGH dual-color break-apart probe, CEBPE dual-color break-apart probe, whole chromosome paint (WCP) probe for chromosome 4, and Chromoprobe Multiprobe-ALL System probe.

RESULTS

The 39-year-old female was diagnosed with B-ALL based on morphologic and immunophenotypic analyses. Conventional cytogenetic analysis showed a karyotype of 47, XX, +4, t(14;14) (q11;q32) [20], which was confirmed by FISH analysis. FISH using IGH-dual-color break-apart probe confirmed involvement of IGH gene in t(14;14) (q11;q32), and FISH using CEBPE dual-color break-apart probe indicated that CEBPE is the partner gene involved in t(14;14) (q11; q32). The patient achieved complete remission (CR) after a round of combined chemotherapy. At the time of follow-up, she had remained CR for more than 6 months.

CONCLUSION

t(14;14) (q11;q32) simultaneously involving IGH and CEBPE genes in B-ALL is a rare but recurrent genetic abnormality that may identify a new subgroup of B-ALL. In B-ALL patients, t(14; 14) (q11; q32) involving IGH/CEBPE translocation may indicate a better prognosis.

Establishment and characterization of a new human acute myelomonocytic leukemia cell line JIH-3

Here, a new acute myelomonocytic leukemia (AMML) cell line, JIH-3, is reported, and its biological characteristics are described. JIH-3 cells were maintained without any cytokines for 27 months. The JIH-3 cell line showed typical myelomonocytic morphological features. Additionally, it mainly expressed myeloid and monocytic markers (CD13, CD14, CD11b, CD15 and CD33), although it also expressed other antigens such as the markers of T and B lymphocytic lineage as well as stem cell, progenitor cell, and natural killer cell-related antigens (CD4, CD5, CD7, CD10, CD22, CD34, CD38, HLADR, CD16/CD56 and CD56); the expression of these markers, suggested that this cell line was in the early stage of myelomonocytic differentiation. Cytogenetic analysis initially showed a karyotype of 46, XY, del(7) (p1?3p2?2). During the passage period, the cells with this karyotype gradually decreased and were replaced by cells with a 45,XY,dic(4;7)(p11;p11),del(15)(q2?2) karyotype. Chromosome painting showed a deletion in the short arm of chromosome 7 for del(7)(p1?3p2?2) and der(4;7)(p11;p11). The latter had larger deleted segment than the former. Fluorescence in situ hybridization (FISH) revealed the dicentric nature of der(4;7), and Multiplex FISH (M-FISH) confirmed that der(4;7) was an unbalanced translocation. A deletion involving the 7p region on dic(4;7)(p11;p11) harbors many genes, including CDC2L5, C7ORF11, C7ORF10 and INHBA. Haploinsufficiency of the genes on 4p, 7p and 15q caused by deletions of 4p, 7p and 15q2?2 that resulted from dic(4;7)(p11;p11) and del(15)(q2?2) may play important roles in leukemogenesis and in the establishment of the JIH-3 cell line. JIH-3 cells did not express multidrug resistance (MDR)-related genes and apoptosis-related genes such as MDR1, multidrug resistance-related protein, lung resistance protein, BCL-2, Bax, GS-π or Fax, only P21 expression was detected, which probably leads the MDR indirectly through inhibition of the activities of cyclin-dependent kinase (CDK). JIH-3 cells had tumorigenic capacity in nude mice. In conclusion, JIH-3 is a new acute myelomonocytic leukemia cell line. It is from a well-characterized background and provides a new useful tool for the study of leukemia patients with a 7p deletion.

[Fluorescence in situ hybridization study of acute myeloid leukemia with cryptic chromosome rearrangements]

OBJECTIVE

To detect specific chromosome rearrangements in acute myeloid leukemia (AML) using interphase-fluorescence in situ hybridization (FISH).

METHODS

All cases were studied by R-band karyotypic analysis using direct method and/or short-term culture for chromosomes preparation. Interphase-FISH was performed in 108 cases of AML with M5, M4, M2, M3 subtypes including 103 cases with normal karyotypes, 4 cases with chromosomal abnormalities other than specific chromosomal rearrangements using chromosome translocation probe such as AML1/ETO, PML/RARα, CBFβ/MYH11 and MLL.

RESULTS

Of 38 cases of M2-AML without t(8;21) on conventional cytogenetics(CC) analysis, 4 cases showed positivity for AML1/ETO fusion transcript, which included 2 cases with typical signal model and 2 with insertion. Of 9 cases of M3-AML without t(15;17) on CC analysis, 6 showed positivity for PML/RARα fusion transcript including 2 with typical signal model, 3 with insertion, one without PML/RARα rearrangement on reverse transcription-PCR and FISH assay using PML/RARα probe. FISH assay using the RARα dual color, break-apart rearrangement probe indicated a partial deletion of RARα. Of 23 cases with M4 or M4EO-AML without inv(16) on CC analysis, 3 showed positivity for CBFβ/MYH11 fusion transcript. Of 38 cases without 11q23 translocation on CC analysis, all cases were negative for MLL rearrangement.

CONCLUSION

Interphase-FISH can detect specific chromosome rearrangements such as AML1/ETO, PML/RARα or CBFβ/MYH11 in some AML cases with normal karyotype, though it seemed less useful for the detection of MLL rearrangement.

The utility of fluorescence in situ hybridization analysis in diagnosing myelodysplastic syndromes is limited to cases with karyotype failure

Fluorescence in situ hybridization (FISH) is being used increasingly in cytogenetic diagnosis of myelodysplastic syndromes (MDS). However, the utility of FISH in this role has not been well-defined. A total of 249 de novo MDS patients were submitted to karyotyping and FISH analysis for -5/del(5)(q31), -7/del(7)(q31), +8, -17/i(17)(q10), del(20)(q12), and -Y. Of the 234 patients with available karyotypic data, 143 cases (60.9%) demonstrated normal karyotype and 91 cases (39.1%) showed abnormal karyotype. FISH confirmed R-banding findings in 96.6% (226/234) of samples with successful karyotyping and detected cytogenetic abnormalities in 46.7% (7/15) of cases with karyotype failure. Of the 3.4% (8/234) patients showing discrepancies between FISH and R-banding, FISH revealed cytogenetic abnormalities in four patients with normal karyotypes and four patients with complex karyotypes. These results highlight FISH analysis has limited value in MDS cases with successful karyotyping and is only informative in MDS cases with karyotype failure.

Mutations of PHF6 are associated with mutations of NOTCH1, JAK1 and rearrangement of SET-NUP214 in T-cell acute lymphoblastic leukemia

BACKGROUND

Mutations in the PHF6 gene were recently described in patients with T-cell acute lymphoblastic leukemia and in those with acute myeloid leukemia. The present study was designed to determine the prevalence of PHF6 gene alterations in T-cell acute lymphoblastic leukemia.

DESIGN AND METHODS

We analyzed the incidence and prognostic value of PHF6 mutations in 96 Chinese patients with T-cell acute lymphoblastic leukemia. PHF6 deletions were screened by real-time quantitative polymerase chain reaction and array-based comparative genomic hybridization. Patients were also investigated for NOTCH1, FBXW7, WT1, and JAK1 mutations together with CALM-AF10, SET-NUP214, and SIL-TAL1 gene rearrangements.

RESULTS

PHF6 mutations were identified in 11/59 (18.6%) adult and 2/37 (5.4%) pediatric cases of T-cell acute lymphoblastic leukemia, these incidences being significantly lower than those recently reported. Although PHF6 is X-linked and mutations have been reported to occur almost exclusively in male patients, we found no sex difference in the incidences of PHF6 mutations in Chinese patients with T-cell acute lymphoblastic leukemia. PHF6 deletions were detected in 2/79 (2.5%) patients analyzed. NOTCH1 mutations, FBXW7 mutations, WT1 mutations, JAK1 mutations, SIL-TAL1 fusions, SET-NUP214 fusions and CALM-AF10 fusions were present in 44/96 (45.8%), 9/96 (9.4%), 4/96 (4.1%), 3/49 (6.1%), 9/48 (18.8%), 3/48 (6.3%) and 0/48 (0%) of patients, respectively. The molecular genetic markers most frequently associated with PHF6 mutations were NOTCH1 mutations (P=0.003), SET-NUP214 rearrangements (P=0.002), and JAK1 mutations (P=0.005). No differences in disease-free survival and overall survival between T-cell acute lymphoblastic leukemia patients with and without PHF6 mutations were observed in a short-term follow-up.

CONCLUSIONS

Overall, these results indicate that, in T-cell acute lymphoblastic leukemia, PHF6 mutations are a recurrent genetic abnormality associated with mutations of NOTCH1, JAK1 and rearrangement of SET-NUP214.

Establishment and characterization of a novel acute myeloid leukemia cell line, JIH-4, carrying a t(16;21)(p11.2;q22) and expressing the FUS-ERG fusion

Human leukemia cell lines are powerful tools in the study of leukemogenesis, particularly for rare but recurrent subtypes such as acute myeloid leukemia (AML) with the t(16;21)(p11.2;q22) and FUS-ERG fusion. Four AML cell lines carrying a t(16;21)(p11.2;q22) have been described previously. We report a novel AML cell line, designated JIH-4, for which karyotypic analysis demonstrated a single abnormality, t(16;21)(p11.2;q22). The FUS-ERG fusion transcript was identified by reverse transcriptase polymerase chain reaction (RT-PCR). Neither Epstein-Barr virus nor mycoplasma was detected in JIH-4 cells. The morphology and immunoprofile of JIH-4 cells display typical features of myelogenous lineage, and short tandem-repeat PCR comparison with the donor patient's bone marrow cells confirm the cell line's authenticity. Tumor masses were found in 50% of inoculated mice 83 days after subcutaneous injection with JIH-4 cells. Our results confirm that JIH-4 cells are derived from the donor patient's leukemia cells and support using the JIH-4 cell line as a valuable tool in the study of leukemogenesis.

[Report of ten cases of hematologic malignancies with idic(20q-) and literature review]

OBJECTIVE

To analyze the clinical and molecular cytogenetic features of hematologic malignancies with idic(20q-).

METHODS

The clinical data of 10 patients with idic (20q-) were analyzed. Karyotyping analysis was carried out with R banding technique. A CEP20 probe was used to perform single-color fluorescence in situ hybridization (FISH). A subtelomeric probe for 20q and a locus-specific probe for 20q12 were used to perform dual-color FISH. The literatures of hematologic malignancies with idic(20q-) were reviewed.

RESULTS

Of the 10 cases, 2 were diagnosed as acute erythroid leukemia, 1 primary myelofibrosis, 3 myelodysplastic syndromes (MDS) and 4 highly suspected (HS-MDS). Karyotype analysis showed that one of the normal chromosome 20 allele was substituted by one or two metacentric isochromosomes smaller than the normal one in all 10 cases. It was confirmed to be der(20)del(20)(q11q13)idic(20)(p11), i.e., idic(20q-) by FISH assay. Partial cells in 2 of the 10 cases had 20q- as the sole karyotypic anomaly.

CONCLUSION

Idic(20q-) results from a pre-existing del(20q) and is strongly associated with MDS and acute erythroid leukemia. Idic(20q-) as a recurrent cytogenetic abnormality is helpful for diagnosing HS-MDS in patients with cytopenia but only slight or absent dysplasia.

A pericentric inv(9)(p22q34) of the der(9)t(9;22)(q34;q11.2) is a recurrent secondary anomaly in Ph-positive leukemia

A pericentric inv(9)(p22q34) of the derivative chromosome 9 that resulted from a standard t(9;22)(q34;q11.2) was identified by R-banding karyotypic analysis and fluorescence in situ hybridization (FISH) assays in 4 (0.18%) of 2,200 Philadelphia chromosome (Ph)-positive leukemia patients, including 3 with chronic myeloid leukemia (CML) in chronic phase and 1 with acute myeloid leukemia (AML) in our hospital since 2004. All four patients had two malignant clones: one with only t(9;22)(q34;q11.2) and another with der(9)t(9;22)(q34;q11.2)inv(9)(p22q34) that resulted in the separation of the ABL1/BCR fusion gene. No metaphases with only inv(9)(p22q34) were seen in any of them. FISH also found a deletion of partial sequence of BCR on der(9)t(9;22)(q34;q11.2)inv(9)(p22q34) in 67.5% of bone marrow cells in the AML patient, but did not detect the deletion of the sequence of ASS/9q34 in these four patients. Reverse transcriptase-polymerase chain reaction revealed a b3a2 type of BCR/ABL1 fusion transcript in all of them, proving their disease to be Ph-positive leukemia. On reviewing the literature, only two solitary Ph-positive leukemia patients have been noticed to have the inv(9)(p22q34) anomaly. These two patients, together with our four documented patients, indicate that inv(9)(p22q34) is a novel, rare, but recurrent secondary chromosomal abnormality for Ph-positive leukemia. Despite receiving hydroxyurea therapy (n = 3 patients), combined chemotherapy (n = 2), even imatinib treatment (n = 1), three patients, including one with AML and two with CML (one of whom progressed into the lymphoblastic blast phase), died with survival times of 28 days, 13 months, and 34 months, respectively. Only one patient with CML remained alive for 5.5 months. Their negative outcome implies that inv(9)(p22q34) has an unfavorable impact on prognosis. Presently, no firm conclusions can be drawn from this study. Because the case number reported here is very small, more patients with this anomaly need to be investigated to elucidate its true prognostic significance.

[Chromosome study on chronic lymphocytic leukemia using CpG-oligodeoxynucleotide as immunostimulant agent]

OBJECTIVE

To investigate whether CpG-oligodeoxynucleotide (CpG-ODN) can improve the detection rate of the karyotypic abnormalities in chronic lymphocytic leukemia (CLL).

METHODS

The bone marrow (BM) or peripheral blood (PB) cells from 57 cases of CLL were collected and cultured with CpG-ODN DSP30+interleukin-2 (IL-2), phytohemagglutinin (PHA), pokeweed (PWM) or IL-2, respectively. Five days later cells were harvested for chromosome preparation. Karyotypic analysis was done using R banding technique. Panel fluorescence in situ hybridization (FISH) was carried out on 19 cases of CLL with normal karyotypes using the following probes: Cen12, D13S25, Rb1, ATM, p53, MYB and IgH. Genomic DNA from 21 cases of them was extracted from BM or PB leukocytes. The immunoglobulin variable heavy chain (IgVH) was amplified by polymerase chain reaction (PCR) and sequenced. CD38 and ZAP70 expressions in the leukemic cells were determined by flow cytometry (FCM).

RESULTS

The detection rate of karyotypic abnormalities in the CpG-ODN+IL-2 group (43.85%) was obviously higher than that in the PHA (15.09%), PWM (17.31%) and IL-2 (3.13%) groups (P<0.01). Fifty-two types of karyotypic abnormalities were found. Among them, trisomy12 (+12) or +12 with other abnormalities were the most common, while translocations were the most frequent structural abnormalities including 3 unbalanced and 11 balanced translocations, among them 7 had rearrangements involving 14q32. Thirteen cases showed one or more abnormalities on FISH including trisomy 12 and p53 deletion each in one case, IgH rearrangement and partial deletion each in one case, 13q14.3 deletion in 11 cases of which 5 cases also had Rb1 deletion, 1 case had Rb1 partial deletion. No case with ATM or MYB deletions was found. PCR detected IgVH mutations in 10/21 cases. FCM showed 10/45 cases were CD38 positive, but 35 /45 were CD38 negative, 11/27 cases expressed ZAP70, but 16/27 did not. Among the 26 cases examined for CD38 and ZAP70 expressions simultaneously, 5 cases were CD38+ZAP70+, 13 were CD38-ZAP70-, 6 were CD38-ZAP70+, and 2 were CD38+ZAP70-, respectively. Statistic analysis showed a correlation between complex karyotype and IgVH without mutation, but no association between karyotype and CD38 or ZAP70 expression was observed.

CONCLUSION

CpG-ODN immunostimulation can obviously raise the detection rate of abnormal karyotypes, especially translocations in CLL. FISH is an important complement to conventional karyotypic analysis. The combination of both methods can provide more comprehensive genetic information for CLL.

A novel t(5;11)(q31;p15) involving the NUP98 gene on 11p15 is associated with a loss of the EGR1 gene on 5q31 in a patient with acute myeloid leukemia

To date, at least 25 translocations involving the NUP98 gene and different partner genes have been reported in the literature. Here, we describe a novel reciprocal t(5;11)(q31;p15) involving NUP98, as revealed by conventional karyotypic analysis using R-banding technique and fluorescence in situ hybridization (FISH) using a BAC RP11-120E20 probe and whole chromosome paint probes for chromosomes 5 and 11 in a 77-year-old woman who was diagnosed as having de novo acute myeloid leukemia. The patient received two courses of intensive combined chemotherapy but did not reach complete remission. She eventually died from the progressive disease, surviving for only 1 month after diagnosis. FISH analysis using WCP5 together with BAC RP11-878F9 or RP11-155N22 demonstrated that the breakpoint of chromosome 5 is located on 5q31. In addition, the EGR1 gene was unexpectedly found to be lost in the FISH study using EGR1 (red)/D5S23, D5S721 (green) dual-color probe. We supposed that the fusion gene created by t(5;11)(q31;p15) consisting of the NUP98 and its partner gene, as well as the loss of the EGR1 gene, may play a cooperative role in leukemogenesis. The partner gene of NUP98 in t(5;11)(q31;p15) is unclear at this time. Further molecular study is required to identify this partner gene in our patient.

[The different signal patterns of two FISH probes in the FISH detection of Ph-positive leukemia and their clinical significance]

OBJECTIVE

To compare the signal patterns of dual color extra-signal BCR/ABL probe (ES-FISH) and dual color dual fusion BCR/ABL probe (D-FISH) in the fluorescence in situ hybridization (FISH) detection of Ph-positive leukemia, and to explore their diagnostic value.

METHODS

ES-FISH probe and D-FISH probe were used, respectively, to detect the BCR/ABL fusion gene in 74 cases with typical t(9;22)(q34;q11) and 37 cases with variant t(9;22)(q34;q11) translocation or complex karyotypic abnormalities containing Ph translocation.

RESULTS

The BCR/ABL fusion gene in all cases with typical t(9;22)(q34;q11) could be detected by both FISH probes. D-FISH had a signal pattern of 1O1G2F, while ES-FISH showed a signal pattern of 2O1G1F. ES-FISH enables the minor breakpoint cluster region to be identified in 9 cases (12.2% ) of Ph-positive leukemia, whereas D-FISH could not differentiate the minor breakpoint cluster region from major breakpoint cluster region. D-FISH could distinguish simple ABL gene deletion from simultaneous deletion of the ABL and BCR genes in 8 cases (10.8%) of Ph-positive leukemia patients, but ES-FISH could not. For variant Ph translocation or complex karyotypic abnormalities containing Ph translocation, each FISH probe showed four or six types of signal pattern, most of which were atypical. The exact interpretation was dependent on conventional karyotypic analysis and FISH on metaphases.

CONCLUSION

ES-FISH and D-FISH probes displayed different signal patterns in Ph-positive leukemia due to their differences in size and covered regions. ES-FISH and D-FISH probes may be selected as better probe for Ph-positive acute lymphocytic leukemia and Ph-positive chronic myeloid leukemia, respectively. When imatinib was used for treatment, there was no preference between ES-FISH and D-FISH probe, because major breakpoint cluster region, minor breakpoint cluster region and partial sequence deletion of derivative chromosome 9, would not affect the prognosis of Ph-positive leukemia. However, considering that ES-FISH probe has a better cost-performance than D-FISH probe does, it is recommended as first choice.

[A clinical and laboratory study on acute myeloid leukemia with t(6;9)(p23;q34)]

OBJECTIVE

To explore the clinical and laboratory features of 6 cases of acute myeloid leukemia (AML) with t(6;9)(p23;q34).

METHODS

Chromosome preparation of bone marrow cells was performed with regular method. R-banding by heating using Giemsa banding technique (RHG) was used for karyotype analysis. The immunoprofile was studied by flow cytometry (FCM) using a panel of monoclonal antibodies. Chromosome painting was performed by using whole chromosome paint probes for chromosomes 6 and 9 in all the 6 cases. The expression of fusion gene DEK/CAN and FLT3-ITD mutation were analyzed by reverse transcription-PCR(RT-PCR).

RESULTS

The t(6;9)(p23;q34) was found in all the 6 cases including 4 cases of M2 and 2 cases of M4. Blast cells were positive for CD13 and CD33 in 6 patients, for HLA-DR in 4 patients, for CD34 and CD117 in 3 cases, for CD38 or CD15 each in 1 case, respectively. A reciprocal translocation between chromosome 6 and 9 was confirmed by chromosome painting technique in the 6 cases. The DEK/CAN fusion gene was found in all the 6 cases, FLT3-ITD mutation was detected in three of them. Follow-up showed that 3 patients died with a survival time of 3 months, 5 months and 6 months, respectively. The other three obtained complete remission and are still alive.

CONCLUSION

The t(6;9)(p23;q34) is a rare recurrent abnormity. AML with t(6;9)(p23;q34) has unique clinical and laboratory features and its prognosis is poor in most cases.

Pulmonary alveolar proteinosis as a terminal complication in a case of myelodysplastic syndrome with idic(20q-)

Secondary pulmonary alveolar proteinosis (PAP) is a rare lung disease that has been reported in 13 cases of myelodysplastic syndromes (MDS). A dicentric isochromosome of deleted chromosome 20q, idic(20q-), is a newly recognized rare, but recurrent, cytogenetic anomaly that has been described in 28 cases of MDS. Recently, we encountered an interesting MDS patient with idic(20q-) and secondary PAP. At presentation, she was a 40-year-old woman with pancytopenia and dysplasia involving 2 cell lineages that were compatible with refractory cytopenia with multilineage dysplasia. A chromosome analysis of bone marrow cells using the R-banding technique revealed a karyotype of 46,XX,-20 and +a small metacentric marker chromosome. Fluorescence in situ hybridization demonstrated this marker chromosome to be idic(20q-). Three years after presentation, her disease was complicated by secondary PAP that was confirmed by chest computed tomographic scans and a thoracoscopic lung biopsy, revealing the characteristic periodic acid Schiff stain-positive materials filling the alveoli. The patient subsequently died of respiratory failure 45 months after diagnosis. To our knowledge, this is the first MDS patient with idic(20q-) and secondary PAP to be reported in the literature. Moreover, this patient is also the 29th MDS case with idic(20q-).

The significance of bone marrow cell morphology and its correlation with cytogenetic features in the diagnosis of MDS-RA patients

Besides cytopenia, dysplasia is crucial characteristic of MDS-RA. To summarize the morphological features that contribute to the diagnosis of MDS-RA, 48 RA patients with abnormal karyotype were analyzed for the features of morphological and cytogenetical abnormalities and the relationships between them. 46 MDS-RA patients with normal karyotype and 207 patients with non-MDS anemia were enrolled into control groups. More conspicuous and diverse dysplasia can be found in abnormal karyotype MDS-RA than those in control groups (P<0.05). Apparent dysplasia in granulocyte and megakaryocytoid lineages may provide valuable evidence for the diagnosis. Dysplasia occurred more frequently in patients with severe chromosome abnormalities.

[Detection of JAK2V617F mutation and its clinical significance in 80 patients with M2 acute myelogenous leukemia]

OBJECTIVE

To explore the prevalence and prognostic significance of JAK2V617F gene mutation in acute myelogenous leukemia M2 (AML-M2) patients.

METHODS

Allele specific polymerase chain reaction (PCR) was used to detect JAK2 gene mutation.

RESULTS

Of 80 de novo AML-M2 patients, 6 at the time of first diagnosis and 1 at relapse were found to have JAK2V617F gene mutation (8.8%, 7/80). Morphologically, the whole blood and bone marrow of the 7 AML-M2 patients with JAK2V617F gene mutation presented a picture of acute leukemia instead of myeloproliferative disorders. Immunophenotypically, bone marrow samples showed myelogenous linage expression. Complete remission was obtained in 4 of 5 AML-M2 patients with JAK2V617F mutation who received treatment, while one patient had no response to the treatment. Follow-up was performed in all the 5 patients, with a median survival of 18.5 months in 4 patients.

CONCLUSION

JAK2V617F gene mutation, as a type-1 mutation, might not be an initial event in the pathogenesis of acute myelogenous leukemia, and its presentation does not mean a poor prognosis in de novo AML patients.

[A quantitative assay for JAK2 mutation in 135 patients with chronic myeloproliferative neoplasms]

OBJECTIVE

To investigate the frequency and mutational status of JAK2 mutation in Chinese patients with chronic myeloproliferative neoplasms (MPN) and study the relative quantitation and clinical implications of mutated JAK2 transcript.

METHODS

JAK2 mutation and the mutational status were screened with amplification-refractory mutation sequencing polymerase chain reaction (ARMS-PCR), the relative quantity of mutated JAK2 mRNA by using capillary electrophoresis.

RESULTS

JAK2V617F mutation was detected in 95 of 135 MPN patients, including 37 (97.4%) of 38 polycythemia vera (PV), 56 (59.6%) of 94 essential thrombocythemia (ET) and 2 of 3 idiopathic myelofibrosis (IMF) patients; the difference between the mutations in PV and ET was significant (P<0.05). Of 95 JAK2V617F patients examined, 18/38 PV patients (47.3%) and 17/94 (18.1%) ET patients and 1 IMF patient were homozygotes, and ET patients showed lower prevalence of homozygote (P<0.05). In 95 MPN patients, the mutated mRNA ratio was higher in homozygote than in heterozygote patients. PV heterozygote patients showed higher levels of mutated JAK2 mRNA than ET heterozygote patients (P<0.05). The levels of JAK2V617F mRNA in patients over 60 years of age were significantly higher than that in those less than 60 years of age (P<0.001). Higher leukocyte counts were observed in PV and ET patients with higher levels of mutated JAK2 mRNA (P<0.05). The presence of JAK2V617F was found to be significantly associated with higher hemoglobin level in ET patients. Cytogenetic analysis was performed in 101 of the 135 patients, the association between abnormal karyotype and JAK2V617F was not found.

CONCLUSION

The ARMS-PCR technique can be used to detect the frequency and mutational status of JAK2V617F mutation, and along with capillary electrophoresis, the estimation of minimal residual disease becomes possible.

[Clinical and laboratory features of patients with CD34(+) acute promyelocytic leukemia]

OBJECTIVE

To explore the expression of CD34 in patients with acute promyelocytic leukemia (APL) and investigate the clinical and laboratory features of CD34(+) APL patients.

METHODS

262 APL patients diagnosed by chromosome analysis and/or fusion gene examination in the last five years were retrospectively analyzed in this study. To survey the expression of CD34 in those patients, all the cases were divided into two groups (CD34(+) APL vs. CD34(-) APL). The clinical features including age, gender, abnormal values of the peripheral hemogram before treatment, the complete remission (CR) rate and the incidence of DIC and laboratory data such as the results of morphology, immunology, cytogenetics and molecular biology (MICM) between those two groups were compared.

RESULTS

Of the 262 APL patients, 38 (14.5%) cases were positive for CD34 expression. There were no statistically significant differences between CD34(+) APL and CD34(-) APL groups in gender and age (P > 0.05). Before treatment, the median level of WBC in CD34(+) APL was 25.92 x 10(9)/L, which was significantly higher than that of CD34(-) APL (5.3 x 10(9)/L, P < 0.05). CD34(+) APL by morphology classification were mostly of the subtypes M3b and M3v (65.8%), while these subtypes in CD34(-) APL (40.3%) were significantly less (P < 0.01). There were no statistically significant differences between the two groups compared in respect of complete remission (CR) rate and the incidence of DIC (P > 0.05). The expression level of CD34 in APL had correlation to the expression level of CD2, CD7 and CD117; the latter three phenotypes in CD34(+) APL were significantly higher than those in CD34(-) APL (P < 0.01). No significant difference was found between those two groups by chromosome analysis, but there was more PML-RAR-alpha transcript short form in CD34(+) APL than that in CD34(-) APL (P < 0.05).

CONCLUSION

CD34(+) acute promyelocytic leukemia is a unique subtype of APL with different biological characteristics.

[Simultaneous presence of ins (15;17),t(2;17;20) and trisomy 8 in a patient with acute promyelocytic leukemia]

OBJECTIVE

To report a rare complex karyotypic abnormalities including ins (15;17),t(2;17;20) and trisomy 8 in a patient with acute promyelocytic leukemia (APL).

METHODS

Chromosomes were prepared after 24 h culture of bone marrow cells. R-banding technique was used to analyze the karyotype. Multiplex fluorescence in situ hybridization (M-FISH), chromosome painting using whole chromosome parint (WCP) 2, 15, 17 and 20 and interphase-FISH (I-FISH) using PML-RARa dual-colour dual-fusion translocation probe were performed to ascertain the essence and origin of the abnormal chromosomes detected by conventional karyotypic analysis.

RESULTS

Karyotypic analysis revealed a karyotype of 47, XY, 2q-, + 8, 17q+ , 20p+ . M-FISH analysis showed a karyotype of 47, XY, t(2;17;20) (q24;q21;p13), + 8, which was confirmed by chromosome painting. PML-RARa fusion gene which lied in the derivative chromosome 15 was detected by I-FISH suggesting a cryptic insertion (15;17)(q22;q21.1q21.3).

CONCLUSION

FISH is a reliable method for characterization of cryptic ins (15;17) and other complex translocations. It should be used in all suspected APL patients lacking t(15;17) by conventional karyotypic analysis.

[Prevalence and clinical significance of FLT3 mutations in acute promyelocytic leukemia]

OBJECTIVE

To evaluate the prevalence of Fms-Like tyrosine kinase 3 (FLT3) mutations including internal tandem duplication (ITD) of juxtamembrane region and point mutation in the second tyrosine kinase domain (TKD) in acute promyelocytic leukemia (APL) and its clinical significance.

METHODS

Bone marrow mononuclear cells from 160 newly diagnosed APL patients were analyzed. Polymerase chain reaction (PCR) was used to detect FLT3-ITD mutations, FLT3-ITD positive samples were further analyzed for the ITD allelic ratio (ITD-AR, mutant-wild type ratio). The FLT3-TKD mutation was analyzed by PCR amplification of exon 20 followed by EcoR V digestion and sequencing.

RESULTS

Out of 160 patients, 30 (18.75%) patients were FLT3-ITD positive, 17 (10.62%) were FLT3-TKD positive, 2 had both of mutations. The initial WBC count and the ratio of short type PML-RAR alpha isoforms in FLT3-ITD positive and FLT3-TKD positive patients were all higher than that in patients with wild-type FLT3 (FLT3-wt) (P < 0.05). For FLT3-ITD positive patients, the incidences of retinoic acid syndrome (RAS) and disseminated intravascular coagulation (DIC) were 41.7% and 65.4%, respectively, being higher than that of FLT3-wt patients, while their complete remission (CR) rate was lower (69.2% vs 90.3%, P < 0.05). For FLT3-TKD positive patients, the incidence of RAS, DIC and CR rate were not significantly different from that of FLT3-wt patients (P > 0.05). FLT3-ITD positive patients had a shorter overall survival (OS) (P < 0.05), but not disease-free survival (DFS) (P > 0.05) as compared with FLT3-wt patients. There was no significant difference in either OS or DFS between FLT3-TKD positive and FLT3-wt patients. The ITD-AR of 30 FLT3-ITD positive patients varied from 0.11 to 6.55 with a median of 1.0. The initial WBC count, incidence of RAS and DIC, CR rate were not significantly different between the patients with ITD-AR greater than 1.0 and lower than 1.0 (P > 0.05).

CONCLUSIONS

FLT3 mutations (FLT3-ITD or FLT3-TKD) are frequently identified in patients with newly diagnosed APL, both mutations are associated with higher initial WBC and short type PML-RAR alpha isoforms. FLT3-ITD mutation is more frequent than FLT3-TKD mutation, and predicts a poorer prognosis, whereas FLT3-TKD mutation does not show the same unfavorable prognostic effect on APL patients.

[Abnormalities of chromosome 17 in myeloid malignancies with complex chromosomal abnormalities]

OBJECTIVE

To investigate the characteristics of the abnormalities of chromosome 17 in myeloid malignancies with complex chromosomal abnormalities (CCAs).

METHODS

Abnormalities of chromosome 17 were analyzed in 73 patients with myeloid malignancies with CCAs showed by R banding and conventional karyotyping, including 21 acute myeloid leukemia (AML), 36 chronic myeloid leukemia (CML) and 16 myelodysplastic syndrome (MDS). All CCAs were further analyzed by multiplex fluorescence in situ hybridization (M-FISH).

RESULTS

Among the 73 myeloid malignancies with CCAs, chromosome 17 was the most frequently involved chromosome. It was found in 46.5% (34/73) of all cases, including 12 AML, 13 CML in blast crisis (BC) and 9 MDS. However, it was not found in the 9 CML cases in chronic phase (CP). The majority of changes were structural rearrangements which were identified in 43.8%(32/73)of all cases, among them the frequency was 52.4% (11/21), 33.3% (12/36) and 56.3% (9/16) in AML, CML and MDS, respectively. Numerical abnormalities were detected in 15.1% (11/73) cases, all were monosomy 17, and the frequency was 25.0% (3/12), 38.5% (5/13) and 33.3% (3/9) in AML, CML and MDS, respectively. Both numerical and structural abnormalities of chromosome 17 were found in 9 cases. Unbalanced translocations involving chromosome 17 were much more frequent than balanced ones. In the 3 groups, 16, 15 and 8 unbalanced translocations were found respectively. Only two kind of balanced translocations including t(15;17) in AML and t(15;17;22) in CML were found. All chromosomes were involved except chromosomes 5, 6 and 22 as partner chromosomes, the most common one was chromosome 15 (8.2%), followed by chromosome 2 (5.4%). Five of the 6 cases with translocation of chromosomes 15 and 17 were acute promyelocytic leukemia, the other case was CML-BC.

CONCLUSION

Abnormalities of chromosome 17 were the most frequently involved chromosomal aberrations in myeloid malignancies, and structural rearrangements were more common. All the numerical abnormalities were monosomy 17, unbalanced translocations were much more frequent than balanced ones.

Establishment and characterization of a new human acute myelocytic leukemia cell line SH-2 with a loss of Y chromosome, a derivative chromosome 16 resulting from an unbalanced translocation between chromosomes 16 and 17, monosomy 17, trisomy 19, and p53 alteration

OBJECTIVE

To report here a new acute myelocytic leukemia (AML) cell line SH-2 and describe its biological characteristics.

MATERIALS AND METHODS

Mononuclear cells isolated from a patient with AML-M2 subtype were passaged by liquid culture medium. Interleukin-3 and bone marrow stromal cells were used to support cell proliferation at the first 3 months. Various methods, including cytogenetic analysis, fluorescence in situ hybridization (FISH), multiplex FISH (M-FISH), reverse transcriptase polymerase chain reaction (RT-PCR), multiplex RT-PCR, short tandem repeat (STR)-PCR, direct sequencing of DNA, clonogenic assay, and tumorigenicity in nude and severe combined immunodeficient (SCID) mice were employed to identify and characterize SH-2 cell line.

RESULTS

SH-2 cells were maintained without cytokine and stromal cells for 3 years. It had no Epstein-Barr virus or mycoplasma contamination. The SH-2 cell line showed typical myelocytic features in morphology and simultaneous strongly expressed myeloid antigens (CD13, 99.6% and CD33, 99.26%) and natural killer (NK)-related antigens (CD56, 99.5% and CD16/56, 99.62%) suggesting that SH-2 is an AML cell line with NK-antigen expression. SH-2 cell line initially showed a karyotype of 45, X, -Y, der(16)t(16;17)(q24;q12), -17, +19. During the passage period, the cells with a hypodiploid karyotype gradually decreased and were replaced by the near-tetraploid cells with a karyotype of 71-105(86), XX, -Y, -Y, der(16)t(16;17)x2, -17, -17, +19, +19. FISH and M-FISH delineated all abnormalities. SH-2 cells had the approximately same morphological, immunophenotypical, and cytogenetic features as the patient's leukemia cells had. STR-PCR provided powerful evidence for the derivation of SH-2 cell line from the patient's leukemia cells. SH-2 cells showed multiple drug resistance (MDR), which may be related to the p53 gene alteration, including the loss of one p53 allele due to the monosomy 17 and a point mutation of CAG to CAT at codon 576 of exon 5 in another p53 allele resulting in the loss of p53 gene function. In addition, SH-2 cell line did not express MDR-related genes, such as MDR1, multidrug resistance-related protein, and lung resistance protein, but expressed apoptosis-related genes, such as Bcl-2, Fas, glutathione S-transferase-pi, and p21, which were also related to the MDR. SH-2 cell line had tumorigenic capacities in nude and SCID mice.

CONCLUSION

Because SH-2 cell line had a clear biology background, it will provide a useful tool for the study of the pathogenesis and treatment strategy of AML with MDR.

[Analysis of complex chromosomal aberrations in patients with myelodysplastic syndromes using multiplex fluorescence in situ hybridization combined with whole chromosome painting]

OBJECTIVE

To explore the value of multiplex fluorescence in situ hybridization (M-FISH) in combination with whole chromosome painting (WCP) in the detection of complex chromosomal aberrations (CCAs) in myelodysplastic syndromes (MDS).

METHODS

M-FISH was used in seven MDS patients with R-banding CCAs to refine the complex chromosomal rearrangements, and to identify cryptic translocations and characterization of marker chromosomes. Dual-color WCP procedures were further performed in 7 cases to confirm some rearrangements detected by M-FISH.

RESULTS

M-FISH confirmed all results of R-banding. The composition and origin of 6 kinds of marker chromosomes, 9 kinds of chromosomes with additional material undetermined and 5 kinds of derivative chromosomes undefined by conventional cytogenetics (CC) were defined after M-FISH analysis; four kinds of cryptic translocations overlooked by CC were found on derivative chromosomes and previously normal appearing chromosomes. In addition, M-FISH revealed some nonrandom aberrations: aberrations involving chromosome 17 and -5/5q- were the two most frequent aberrations. Some misclassified and missed chromosomal aberrations by M-FISH were corrected by WCP.

CONCLUSION

M-FISH is a powerful molecular cytogenetic tool in clarification of CCAs. Complementary WCP helps us to identify misclassified and missed chromosomal aberrations by M-FISH. CC in combination with molecular cytogenetic techniques, such as M-FISH and WCP, can unravel complex chromosomal aberrations more precisely.

[Fluorescence in situ hybridization identifies complex chromosomal aberrations in multiple myeloma]

OBJECTIVE

To explore the value of the technique of multiplex fluorescence in sit hybridization (M-FISH) combined with interphase fluorescence in situ hybridization (FISH) in the identification of the chromosomal aberrations in multiple myeloma (MM) and to investigate the frequency of 13q14 deletion, IgH translocations and 17p13 deletion.

METHODS

Seven MM patients with complex chromosomal abnormalities (CCAs) were analyzed by combining the technique of conventional cytogenetics (CC) with M-FISH and FISH.

RESULTS

M-FISH identified the aberrations which were undetected by CC, including twelve kinds of numeral aberrations and twenty-nine kinds of structural aberrations, In addition, abnormalities of chromosome 1, chromosomes 13 deletion and IgH translocations were the most frequent aberrations. Using the LSI D13S319 probe specific for 13q14, we observed a deletion of 13q14 in 6 MM patients; using the LSI p53 probe specific for 17p13, we observed p53 deletion in 4 MM patients; using the LSI IGHC/IGHV probe specific for 14q32, we observed a translocation involving 14q32 in 5 MM patients (43.5%), two translocations in two cases (case 6 and 7).

CONCLUSION

M-FISH combined with FISH could refine the cytogenetics of MM patients and detect the missed abnormalities or correct the misidentified abnormalities analyzed by CC. It provides an ideal method for the research of chromosomal aberrations in MM.

Two novel translocations disrupt the RUNX1 gene in acute myeloid leukemia

Translocations involving 21q22 are commonly observed in both de novo and therapy-related acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). They often result in the disruption of RUNX1 and give rise to fusion genes consisting of RUNX1 and different partner genes, which contribute to leukemogenesis. To date, at least 21 such translocations are known from the literature. Here we report two novel translocations involving the RUNX1 gene: t(1;21)(q12;q22) in a 53-year-old woman with AML-M5b and t(11;21)(q13;q22) in a 65-year-old man with AML-M2. The abnormalities revealed by R-banding karyotypic analysis were confirmed with interphase and metaphase fluorescence in situ hybridization (FISH), chromosome painting, and M-FISH.

Analysis of NPM1 Gene Mutations in Chinese Adults with Acute Myeloid Leukemia

Many European groups have recently described that mutations at exon-12 of the nucleophosmin (NPM1) gene are the most frequent genetic lesion in patients with acute myeloid leukemia (AML), especially in the presence of a normal karyotype. This study explored the prevalence and clinical profile of NPM1 mutations in a cohort of 156 Chinese adults with AML. NPM1 exon-12 mutations were detected using direct sequencing or fragment analysis of genomic DNA polymerase chain reaction products. NPM1 mutations were present in 28.2% of the overall population, including 1/1 (100%) of M0, 11/27 (40.7%) of M1, 11/46 (23.9%) of M2, 0/29 (0%) of M3, 2/9 (22.2%) of M4, 18/39 (46.2%) of M5, and 1/5 (20.0%) of M6. NPM1 gene mutations were more prevalent in patients with a normal karyotype (37 of 90; 41.1%) when compared with patients with karyotypic abnormalities (7 of 66; 10.6%;P < .001). Sequence analysis of 25 NPM1-mutated cases revealed known mutations (type A, D, N(M), and P(M)) as well as one novel sequence variation (here named as type S). All mutational types were heterozygous and showed a 4 bp insertion. NPM1 mutations were significantly associated with old age (P < .05), high peripheral white blood cell count (P < .05), and the subtypes of French-American-British categories M1/M5, but negatively associated with expression of CD34 (P < .05) and CD117 (P < .05). Thus, this study provides the methods of NPM1 exon-12 mutations detection and related clinical data of NPM1 mutated cases in a Chinese population.

[Molecular genetics in chronic myeloid leukemia with variant Ph translocation]

OBJECTIVE

To explore the value of fluorescence in situ hybridization (FISH) and multiplex fluorescence in situ hybridization (M-FISH) techniques in the detection of genetic changes in chronic myeloid leukemia (CML) with variant Philadelphia translocation (vPh).

METHODS

Cytogenetic preparations from 10 CML patients with vPh confirmed by R banding were assayed with dual color dual fusion FISH technique. If only one fusion signal was detected in interphase cells, metaphase cells were observed to determine if there were derivative chromosome 9[der (9)] deletions. Meanwhile, the same cytogenetic preparations were assayed with M-FISH technique.

RESULTS

Of the 10 CML patients with vPh, 5 were detected with der (9) deletions by FISH technique. M-FISH technique revealed that besides the chromosome 22, chromosomes 1, 3, 5, 6, 8, 10, 11 and 17 were also involved in the vPh. M-FISH technique also detected the abnormalities which were not found with conventional cytogenetics (CC), including two never reported abnormalities.

CONCLUSION

The combination of CC, FISH and M-FISH technique could refine the genetic diagnosis of CML with vPh.

[Clinical and experimental retrospective analysis on acute leukemia with trisomy 4 cell]

OBJECTIVE

To explore the clinical and experimental features of acute leukemia (AL) with trisomy 4.

METHODS

A retrospective analysis on the clinical and laboratory data of 21 cases of AL with trisomy 4 was performed. Chromosomes were prepared using direct method and/or short-term (24 h) cultures of bone marrow cells. Karyotypic analysis was carried out by using R-banding technique. Thirteen cases were studied by interphase fluorescence in situ hybridization (FISH) by using a chromosome 4-specific alpha -satellite DNA probe labeled by spectrum Green to ascertain the presence of a clone with trisomy 4. Five cases with t (8; 21) revealed by karyotypic analysis were detected by dual-color FISH using t (8; 21) translocation probe to confirm the AML1/ETO rearrangement.

RESULTS

All the patients with AL and trisomy 4 were with de novo AL except two cases with secondary AL. M2 was the most frequent Franch-American-British(FAB) subtype in this series (9/21 cases). The initial leukocyte count more than 10x 10(9)/L was seen in 16 cases. An enlargement of liver, spleen and/or lymph nodes in varying degrees was found in 15 cases. Among 15 cases received immunophenotypic analysis, 11 cases showed CD34 positivity and 6 cases co-expressed myeloid and lymphocyte antigens. Karyotypic analysis disclosed clonal trisomy 4 in 18 cases and one cell with +4 in 3 cases. Isolated trisomy 4 was found in 7 cases, while 14 cases had other abnormalities besides trisomy 4 among which t (8; 21) was found in 8 cases. Dual-color FISH confirmed that all 13 cases including 3 cases having one cell with +4 on karyotypic analysis had clonal trisomy 4. Dual-color FISH confirmed that all 5 cases with t (8; 21) had AML1/ETO rearrangement.

CONCLUSION

AL patients with trisomy 4 have unique clinical and experimental features and a poor prognosis.

Analysis of JAK2(V617F) mutation in Chinese patients with myeloproliferative disorders

It is now well-recognized that the activating JAK2(V617F) mutation occurs in the majority of patients with polycythemia vera (PV) and approximately half of those with either essential thrombocythemia (ET) or myelofibrosis with myeloid metaplasia (MMM). Here we analyzed JAK2(V617F) mutation in 137 Chinese patients with myeloproliferative disorders by allele-specific polymerase chain reaction (PCR). DNA was extracted from methanol/acetic acid-fixed cells that had been routinely prepared for cytogenetic analysis. A single point mutation (Val617Phe) was identified in JAK2 in 42 (73.7%) of 57 patients with PV, 40 (58.8%) of 68 with ET, and eight (66.7%) of 12 with MMM.