Clonal origin of the Philadelphia chromosome and chronic myeloid leukaemia: evidence from a sex chromosome mosaic

Constitutional chromosome aberrations as pathogenetic events in hematologic malignancies

A predisposition to tumor development is associated with some constitutional chromosomal abnormalities. Investigations of families with an apparent hereditary cancer and constitutional chromosome rearrangements have led to the molecular identification of tumor suppressor genes. Under the somatic mutation theory for the development of cancer, two mutational events are required. The first step may be a constitutional event and the second an acquired genetic mutation. Cytogenetic studies were performed on 5633 bone marrow specimens from patients with hematologic malignancies from a single institution. Fifty cases of constitutional chromosome aberrations were detected. Data collected from the literature and from our series are reviewed and compared with the incidence of specific constitutional chromosome aberrations in the newborn population. Possible mechanisms that may predispose individuals with constitutional chromosome aberrations to the development of a hematologic malignancy are reviewed.

De novo germinoma in the brain in association with Klinefelter's syndrome: case report and review of the literature

BACKGROUND

There are no previous reports about de novo germ cell tumors without any past history of germ cell tumor. We describe a case of de novo cerebral germinoma in association with Klinefelter's syndrome.

CASE DESCRIPTION

A boy had undergone growth hormone therapy for dwarfism because of hypopituitarism from 10 to 17 years old. The result of karyotyping at the age of 13 was 47,XXY. Magnetic resonance images (MRI) of the brain at the age of 17 years showed no lesions. Two years later, at the age of 19, the patient noticed onset of mild right hemiparesis. MR imaging revealed the existence of a brain tumor in the left temporal lobe and hypothalamus. The patient underwent an operation and the histologic diagnosis of the lesion was germinoma. After postoperative chemotherapy and radiation therapy, the lesion disappeared and the patient was discharged uneventfully.

CONCLUSIONS

To the best of the authors' knowledge, this is the first reported case of a germ cell tumor to be de novo without any past history of other germ cell tumor and the seventh case in which it occurred in association with Klinefelter's syndrome.

Chronic myelogenous leukemia as a paradigm of early cancer and possible curative strategies

The chronological history of the important discoveries leading to our present understanding of the essential clinical, biological, biochemical, and molecular features of chronic myelogenous leukemia (CML) are first reviewed, focusing in particular on abnormalities that are responsible for the massive myeloid expansion. CML is an excellent target for the development of selective treatment because of its highly consistent genetic abnormality and qualitatively different fusion gene product, p210(bcr-abl). It is likely that the multiple signaling pathways dysregulated by p210(bcr-abl) are sufficient to explain all the initial manifestations of the chronic phase of the disease, although understanding of the circuitry is still very incomplete. Evidence is presented that the signaling pathways that are constitutively activated in CML stem cells and primitive progenitors cooperate with cytokines to increase the proportion of stem cells that are activated and thereby increase recruitment into the committed progenitor cell pool, and that this increased activation is probably the primary cause of the massive myeloid expansion in CML. The cooperative interactions between Bcr-Abl and cytokine-activated pathways interfere with the synergistic interactions between multiple cytokines that are normally required for the activation of stem cells, while at the same time causing numerous subtle biochemical and functional abnormalities in the later progenitors and precursor cells. The committed CML progenitors have discordant maturation and reduced proliferative capacity compared to normal committed progenitors, and like them, are destined to die after a limited number of divisions. Thus, the primary goal of any curative strategy must be to eliminate all Philadelphia positive (Ph+) primitive cells that are capable of symmetric division and thereby able to expand the Ph+ stem cell pool and recreate the disease. Several highly potent and moderately selective inhibitors of Bcr-Abl kinase have recently been discovered that are capable of killing the majority of actively proliferating early CML progenitors with minimal effects on normal progenitors. However, like their normal counterparts, most of the CML primitive stem cells are quiescent at any given time and are relatively invulnerable to the Bcr-Abl kinase inhibitors as well as other drugs. We propose that survival of dormant Ph+ stem cells may be the most important reason for the inability to cure the disease during initial treatment, while resistance to the inhibitors and other drugs becomes increasingly important later. An outline of a possible curative strategy is presented that attempts to take advantage of the subtle differences in the proliferative behavior of normal and Ph+ stem cells and the newly discovered selective inhibitors of Bcr-Abl. Leukemia (2003) 17, 1211-1262. doi:10.1038/sj.leu.2402912

Hematologic malignancies and Klinefelter syndrome. a chance association?

Klinefelter syndrome was first described in 1942 as an endocrine disorder characterized by gynecomastia, hypogonadism, small testes, and elevated levels of follicle-stimulating hormone. An extra X chromosome (i.e., 47,XXY) was subsequently demonstrated in these patients and an increased incidence of leukemia and lymphoma has been described. We report a retrospective study of a series of unselected patients with Klinefelter syndrome diagnosed by cytogenetic studies and the occurrence of hematologic malignancies. The literature is also reviewed.

Chronic myelogenous leukemia and Klinefelter's syndrome

A case of chronic myelogenous leukemia with Klinefelter's syndrome mosaicism in a 27-yr-old male is reported. Cytogenetic analysis provided evidence that the Philadelphia chromosome occurred monoclonally in the XXY cells but not in the XY cells.

Chronic leukemias of childhood

Chronic leukemias account for fewer than 5 per cent of childhood hematologic malignancies. The various subtypes are chronic mylocytic leukemia (adult, juvenile, and familial), chronic myelomonocytic leukemia chronic monocytic leukemia, and chronic lymphocytic leukemia. The most common of these, adult-type chronic myelocytic leukemia, is characterized by specific cytogenetic alterations; recent advances in molecular biology are linking these genetic events to the pathophysiology and course of this fascinating neoplasm.

Clinicopathological characteristics of acute lymphoblastic leukemia with the 4;11 chromosome translocation

Analysis of the bone marrow karyotype in 109 consecutive untreated patients with acute lymphoblastic leukemia (ALL) by the G-banding technique revealed the presence of a translocation between specific sites on the long arms of chromosomes 4 and 11, [t(4;11) (q21;q23)] in 3 adults and 2 children. Splenomegaly was present in all patients, marked leukocytosis in 4, and retinal hemorrhages in the absence of significant mucocutaneous bleeding in 3. Complete remission defined by conventional morphological criteria was achieved with combination chemotherapy in all instances, but the duration of remission was brief in 3. Three patients were studied in relapse, and clonal evolution was found to have occurred in 2. Analysis of our data in conjunction with other published reports suggests this specific karyotypic abnormality characterizes a small subgroup of ALL in which there is a strong association with recognized clinical and laboratory indices of poor prognosis, in particular its frequent occurrence in children under the age of 2.5 yr. There is a propensity to undergo clonal evolution, and the possibility exists that such a development is associated with poor prognosis.

Choriocarcinoma, thyrotoxicosis, and the Klinefelter syndrome

A patient with the combined features of Klinefelter syndrome, thyrotoxicosis and a primary mediastinal choriocarcinoma is reported. Review of the literature reveals that extragonadal germ cell tumors appear to be significantly associated with the Klinefelter syndrome. The reason for this is presently unclear but may involve an unusual propensity of the extragonadal aneuploid germ cell to undergo malignant degeneration.

The clinical and cytogenetic significance of C-banding on chromosome #9 in patients with Ph1-positive chronic myeloid leukemia

The C-band polymorphism of chromosome #9 in 18 patients with chronic myeloid leukemia (CML) with a Philadelphia chromosome (Ph1) translocation between chromosomes #9 and #22 was examined using C- and Q-banding techniques on the same metaphases and the classification proposed by Patil and Lubs [1]. The C-band polymorphism of chromosome #9 in CML was found not to differ in leukemic cells with the Ph1 and phytohemagglutinin-stimulated lymphocytes without the Ph1 and to have a clonal origin, i.e., to arise from a single cell in which the Ph1 translocation has taken place. A comparison of the C-band polymorphism of chromosome #9, survival after diagnosis of the disease, and abnormal chromosomes in addition to the Ph1 indicates some interesting aspects. Patients with the smallest C-band (level 1) on chromosome #9 not involved in the Ph1 translocation and with a relatively large C-band (level 2) on chromosome #9 with the Ph1 translocation (C9-1,2) tend to have no clonal evolution and short survival after diagnosis of the disease. On the other hand, patients with other types of C-band patterns tend to have evidence of clonal evolution and long survival. This study suggests that the C-banding pattern in Ph1-positive CML might be utilized as a prognostic parameter in the disease and that the C-segment might have biological activity.

Suprasellar germinoma in association with Klinefelter's syndrome. Case report

✓ A case is presented of suprasellar germinoma in a 20-year-old man with Klinefelter's syndrome. Hypogonadism is known to be a characteristic of Klinefelter's syndrome, and has often been described in cases of suprasellar germinoma. Thus, both pathological entities may mimic one another. It is emphasized that a chromosomal karyotype should be determined in every case of intracranial germ-cell tumor associated with hypogonadism.

Clonal origin of the Philadelphia translocation in chronic myeloid leukemia demonstrated in somatic cell hybrids using an adenylate kinase-1 polymorphism

Hybrid cell lines were derived from fusion of rodent cells with leukocytes from a t(9q+; 22q-)-positive chronic myeloid leukemia (CML) patient carrying a chromosome No. 9-linked adenylate kinase-1 (AK1) polymorphism (AK1 1-2). The AK1*2 allele was consistently expressed when 9q+ was present, whereas the AK1*1-coded isozyme was formed when the normal chromosome No. 9 was present. These results provide additional data confirming the clonal origin of the Ph1 translocation in CML.

Chronic myelogenous leukemia in the monosomic cell line of a fertile Turner syndrome mosaic (45,X/46,XX)

Malignancy in patients with constitutional chromosome abnormality is of interest not only because it permits insights into the relationship between the chromosome abnormality and cancer, but also because it provides opportunities to address such questions as the clonality and evolution of tumors. We report Ph1-positive chronic myelogenous leukemia (CML) in a 50-year-old mosaic (45,X/46,XX) Turner syndrome patient whose leukemia was restricted to the monosomic cell line. Our extensive cytogenetic studies of this patient demonstrated that non-leukemic normal cells persisted in the marrow and were able to proliferate during a period of temporary suppression of the leukemic clone following aggressive treatment.

Klinefelter's syndrome and mediastinal germ cell neoplasms

We describe 2 patients with Klinefelter's syndrome in whom mediastinal germ cell neoplasms developed. This association also has been noted in the literature in 6 other cases. The pathogenesis of these otherwise rare neoplasms probably is related to the genetic abnormality and the abnormal hormonal status in Klinefelter's syndrome. Patients with Klinefelter's syndrome appear to have an increased risk of development of extragonadal mediastinal germ cell neoplasms and should be followed closely, while patients with mediastinal germ cell neoplasms should have karyotypes performed.

Different cell clones in bone marrow and spleen of a patient with chronic myelocytic leukemia (CML) in blastic phase

The chromosome study of a patient with chronic myelocytic leukemia in blastic phase revealed a 46,XY,Ph1/47,XY,Ph1,+8 cytogenetic constitution in bone marrow cells and a 46,XY,Ph1/48,XY,2Ph1,+19 cytogenetic constitution in spleen cells. As the cell clones exhibiting chromosome abnormalities in addition to the Ph1 chromosome evolved apparently independently, it is suggested that the acute transformation had a bifocal, myeloid and splenic origin.

Chronic myelocytic leukemia: clonal origin in a stem cell common to the granulocyte, erythrocyte, platelet and monocyte/macrophage

Glucose-6-phosphate dehydrogenase (G-6-PD) isoenzymes types of granulocytes were determined in eight women with chronic myelocytic leukemia (CML). The patients were heterozygous at the X-linked G-6-PD locus for the common gene, GdB, and a variant, such as GdA, so that both B and A enzyme types were found in skin cells. In contrast to these normal cells, only one G-6-PD type was found in CML granulocytes. The fact that such single-enzyme phenotypes are found in CML granulocytes, but not in nonleukemic granulocytes, provides strong evidence that the disease has a clonal origin. Single-enzyme phenotypes were also found in erythrocytes, platelets and cultured blood macrophages indicating that these cells have a common stem cell which is the site of the abnormality in CML. In the one studied patient, no evidence was found for involvement of cultured marrow fibroblasts. Clonal origin of CML virtually excludes cell recruitment as a sole pathogenetic mechanism. Either the leukemia arises as a consequence of a rare initial event in a single cell, or a series of events occurs in a clone such that it evolves into CML, or both.

Additional chromosomal indication for the unicellular origin of chronic myelocytic leukemia

In a female patient with chronic myelocytic leukemia (CML) the translocation 9q +; 22q was constantly found to involve only the variant chromosome 9 with an unusually long secondary constriction. The finding indicates a unicellular origin of CML.