Derivative chromosome 9 deletions in chronic myeloid leukaemia: interpretation of atypical D-FISH pattern

BACKGROUND/AIMS: New molecular cytogenetic techniques are increasingly applied as a routine investigative tool in haematological malignancies, both at diagnosis and subsequent monitoring. This report describes the interpretation of atypical signal patterns encountered using BCR-ABL dual colour dual fusion fluorescence in situ hybridisation (D-FISH) translocation probes in chronic myeloid leukaemia (CML). METHODS: Interphase FISH experiments were carried out using BCR-ABL D-FISH probes in 46 patients with CML at diagnosis and during subsequent disease monitoring. Atypical hybridisation signal patterns were characterised by molecular cytogenetic techniques and correlated with conventional karyotyping. RESULTS: Two patients showed atypical interphase D-FISH patterns with one orange, one green, and one fusion (1O1G1F) signal. The presence of BCR-ABL gene fusion was documented by a dual colour single fusion (S-FISH) probe. The submicroscopic deletion of the ABL-BCR fusion gene on the derivative chromosome 9 in these cases was subsequently characterised by metaphase FISH on relocated G banded metaphases. CONCLUSIONS: Atypical interphase D-FISH patterns should not be interpreted in isolation and should be considered in conjunction with other cytogenetic or molecular genetic investigations.     

t(15;17) in a promyelocytic form of chronic myeloid leukemia blastic crisis

Two simultaneous translocations, t(15;17) and t(9;22), have been observed in a chronic myelogenous leukemia patient with acute promyelocytic blastic crisis. After remission obtention only karyotypes with t(9;22) were present. The occurrence of the two translocations in the same cell argues in favor of the specificity of t(15;17) versus acute promyelocytic differentiation.     

A t(3;5) in blastic phase of a Philadelphia chromosome-negative chronic myeloid leukemia

Serial cytogenetic analyses from the bone marrow of a patient with blastic phase of a Philadelphia chromosome-negative chronic myeloid leukemia revealed a t(3;5)(p21;q31). The literature on translocations involving chromosome 3 and the long arm of chromosome 5 is reviewed. The importance of breakpoints in band 5q31 is discussed.     

Complex translocation t(3;9;22) and paracentric inversion of chromosome 3 in blastic crisis of chronic myeloid leukemia

We report a complex rearrangement observed in both the short and long arms of chromosome #3 in a patient with Ph-positive chronic myeloid leukemia in blastic crisis and without thrombopoietic abnormalities. The rearrangement consisted of a complex translocation, t(3;9;22)(p21;q34;q11), and a paracentric inversion of the long arm of the same chromosome #3 involved in the translocation. Involvement of chromosome #3 in complex translocations in chronic myeloid leukemia and the relationship between 3q anomalies and thrombopoietic diseases are discussed.     

Philadelphia chromosome negative acute lymphoblastic leukemia preceding Philadelphia positive chronic myelogenous leukemia

A patient with Philadelphia chromosome (Ph) negative acute lymphoblastic leukemia (ALL, FAB type L1) developed Ph-positive chronic myelogenous leukemia (CML) after more than 2 years in complete remission. Subsequently, Ph-positive lymphoblastic transformation occurred, which was again successfully treated. Thereafter, the CML state was interrupted twice more by blast crisis. The additional chromosomal abnormalities were atypical for Ph-positive CML. The course is interpreted as a possible example of the multistep development of CML. Blastic transformation occurring prior to the Ph chromosome has been reported in only two cases previously.     

New types of unusual and complex Philadelphia chromosome (Ph1) translocations in chronic myeloid leukemia

Nine cases of Philadelphia chromosome-positive chronic myeloid leukemia with an aberrant translocation are reported. In three cases an unusual translocation was found, the recipient chromosome being Nos. 14, 17, and 18, respectively. In six cases the translocation involved a third chromosome in addition to Nos. 9 and 22: there were two cases involving chromosome No. 1, two involving chromosome No. 14, one involving chromosome No. 3, and one involving chromosome No. 12. The clinical significance of the aberrant translocations and the translocation mechanism is discussed.     

A hypothetical model to explain the 'termination' of chronic myeloid leukemia into blastic crisis

Chronic myeloid leukemia is characterised by two discrete phases, a 'benign' phase which terminates into an 'acute' phase. Various explanations have been given to explain the cause of 'blastic' crisis in CML. But the consistency and regularity with which blast crisis occurs and the irregularity with which the factors which are ascribed to cause it (e.g. additional chromosomal abnormalities, change in bcr/abl rearrangement, etc. occur, suggests that CML-BC is not a stochastic process in the natural history of CML but is predetermined at the time of the first mutation in the stem cell. A hypothetical model is put forward proposing this. Different points supporting the model are discussed. The most important implication of this model would be to provide an insight that should lead to the development of more selective and appropriate treatment strategies for this disease.     

Ph-positive chronic myeloid leukemia with t(8;21)(q22;q22) in blastic crisis.

A patient diagnosed with chronic myeloid leukemia was studied periodically during his illness. The result showed the presence of a Philadelphia (Ph) chromosome by a 9;22 translocation as a single abnormality to the time of blastic crisis. At that time, the chromosome studies showed a clonal evolution. Furthermore, a second derivated line was added to the Ph line. This new anomaly consisted of a 8;21 translocation, considered as specific of M2 type acute nonlymphoblastic leukemia of French-American-British classification.     

Multiplex fluorescence in situ hybridization and cross species color banding of a case of chronic myeloid leukemia in blastic crisis with a complex Philadelphia translocation

Exciting new techniques in molecular cytogenetics--namely, spectral karyotyping, multiplex fluorescence in situ hybridization (M-FISH), and cross species color banding--have been recently developed. An increasing number of reports demonstrate the success of these procedures in providing additional cytogenetic information--identifying marker chromosomes and revealing the presence of previously undetected chromosomal changes. However, these procedures have their limitations, and their absolute sensitivity in the accurate identification of subtle chromosomal abnormalities remains to be established. M-FISH and color banding have been applied to a case of chronic myeloid leukemia with a complex Philadelphia translocation involving chromosomes 9, 17, and 22, which had initially been identified from G-banded chromosome analysis. The abnormalities were confirmed by chromosome "painting" and specific probes. Although M-FISH and color banding revealed no additional cryptic chromosomal changes, this study has clearly demonstrated the success of these multiple color FISH approaches in the accurate characterization of a complex rearrangement with subtle abnormalities.     

Spontaneous splenic rupture in a hemodialysis patient

Spontaneous splenic rupture (SSR) in a patient undergoing hemodialysis has been described as an extremely rare and potentially fatal complication. We report here spontaneous splenic rupture in a 52-year-old woman undergoing regular hemodialysis for end-stage renal disease (ESRD). She complained of colicky abdominal pain in the left upper quadrant area and dizziness when she assumed an upright posture. Her vital signs revealed low blood pressure and tachycardia, which was suggestive of hypovolemic shock. Abdomen CT scan showed splenic hematoma and hemoperitoneum. However, she had no history of any event triggering the splenic rupture. An exploratory laparotomy showed a ruptured spleen and an emergency splenectomy was performed. We suggest that spontaneous spleen rupture may be attributed to uremic coagulopathy and heparin-induced coagulopathy.     

Reciprocal translocation between chromosomes 8 and 9 in atypical chronic myeloid leukaemia.

A balanced translocation t(8;9) (p11;q34) was present in the peripheral blood, bone marrow, and spleen cells of a patient with Ph negative chronic myeloid leukaemia. Subsequent transformation into acute leukaemia was associated with the emergence of trisomy 8 and der(8)(8qter----cen----8p11::9q34----9qter). This is the third reported case of t(8;9) (p11;q34) and raises the question of the role of c-abl in the pathogenesis of this myeloproliferative disorder.     

Translocation 3;21 in Philadelphia chromosome positive chronic myeloid leukemia at diagnosis

We describe a further case of Philadelphia chromosome-positive chronic myeloid leukemia with a t(3;21)(q26.2;q22) present in the chronic phase. Blastic transformation occurred 8 months after presentation. The presence of the t(3;21) may indicate a poor prognosis.     

A new translocation in chronic myeloid leukemia--t(4;9;22)--resulting in a masked Philadelphia chromosome

A patient with chronic myeloid leukemia is described in whom a novel complex translocation was found among chromosomes #4, #9, and #22, resulting in a "masked" Philadelphia chromosome. The breakpoint in chromosome #4 (band q21) is in the same region as the breakpoint seen in the t(4;11), which is associated with some forms of acute leukemia.     

Extramedullary transformation of chronic myeloid leukaemia with a unique chromosome pattern.

A case of extramedullary myeloblastic transformation of chronic myeloid leukaemia is reported. This was characterised by an unusual clinical and haematological course and showed a unique cytogenetic pattern.     

Atypical Ph negative chronic myeloid leukaemia presenting as sudden profound deafness.

A patient with atypical Ph negative chronic myeloid leukaemia presented with the sudden onset of profound deafness. He survived only eight months. Detailed histological investigation performed at necropsy showed loss of ganglion cells and afferent nerve fibres in the cochlea and vestibule associated with extensive fibrosis and new bone formation in the labyrinthine spaces. Both leucophoresis and high dose chemotherapy capable of rapid cytoreduction are recommended in patients with chronic myeloid leukaemia with profound hearing loss, as conventional chemotherapy is rarely followed by recovery.     

A case of chronic myeloid leukemia with a "masked" Philadelphia chromosome

A case is described of a 67-year-old man with chronic myeloid leukemia and a "masked" Philadelphia chromosome due to a translocation between chromosomes #4 and #22. The significance of this case in relation to the possible pathogenesis of chronic myeloid leukemia is discussed.     

The cytogenetics of chronic myelocytic leukemia (CML): Chronic phase and blastic crisis

Some of the recent cytogenetic findings in chronic myelocytic leukemia have been summarized and the significance of the Philadelphia-chromosome, including those resulting from unusual translocations, and other karyotypic changes discussed in relation to survival, blastic phase (including its extramedullary origin), and therapy.