Evidence that chromosome band 22q12 is concerned with cell proliferation in chronic myeloid leukaemia

Regional localization and molecular characterization of a DNA sequence on the long arm of chromosome 22

A human genomic DNA fragment, p22hom13 (D22S16), was isolated from a chromosome 22-specific library. After elimination of repetitive sequences, a single copy BamHI-EcoRI fragment was subcloned into pTZ18. By using mouse/human somatic cell hybrids and in situ hybridization, the new DNA probe was mapped to chromosome 22q13-qter. Its application in the analysis of the distal part of chromosome 22 and its diagnostic use in translocations are discussed.

Essential thrombocytosis with the Philadelphia chromosome (Ph')

Essential thrombocytosis is a myeloproliferative disease not known to have consistent cytogenetic abnormalities. A 46-year-old black woman with essential thrombocytosis and a Philadelphia chromosome is reported. Iron deficiency and tuberculosis were present but when effectively treated did not result in resolution of thrombocytosis. Megakaryocytic hyperplasia of bone marrow, abnormal platelet function studies and a compatible clinical state suggested the diagnosis of essential thrombocytosis. The diagnostic criteria for other myeloproliferative diseases were not met. The Philadelphia chromosome was consistently obtained from bone marrow preparations. We conclude that the Philadelphia chromosome may be found in essential thrombocytosis as well as other, previously reported, myeloproliferative diseases.

High resolution banding of chronic myeloid leukemia chromosomes

Bone marrow aspirates from 29 patients with chronic myeloid leukemia were studied using the methotrexate synchronization culture method. Successful cytogenetic preparations exhibiting long and well banded chromosomes were obtained from all of them. The standard t(9;22) was seen in 23 patients, four had variant translocations, and two were Ph-negative. Of the four patients with variant translocations, one had a simple translocation in which the missing segment of chromosome #22 was translocated onto the short arm of chromosome #9. The remaining three patients had complex translocations. The first involved chromosomes #11, #19, and #22, the second involved chromosomes #9, #11, and #22, and the third involved chromosomes #9, #14, and #22. Karyotypic abnormalities in addition to the Ph chromosome were seen in four patients: in three these changes developed during the chronic phase and in one during the blastic phase. Using Q-, R-, and G-banding techniques, we found that the breakpoint on chromosome #22 is just below the centromere, namely in band 22q11.2 and on chromosome #9 in band 9q34.1. The standard translocation, therefore, can be written as t(9;22)(q34.1;q11.2). Furthermore, the breakpoint on 22q appeared to be identical in all cases with standard as well as the variant translocations. Our results show that the methotrexate synchronization method permits consistent high resolution banding of CML chromosomes, and support the concept that there is no difference in the amount of material translocated from 22q in different patients.

High resolution chromosomes of the t(9;22) positive leukemias

A combined bromodeoxyuridine (BrdU) and actinomycin D (AMD) treatment of methotrexate (MTX) synchronized bone marrow cells from four patients with chronic myelogenous leukemia (CML), and two each with acute lymphocytic (ALL) and acute nonlymphocytic (ANLL) leukemia were used to define the breakpoints involved in the t(9;22) found in subgroups of these three disorders. An additional 20 patients with CML were studied with the MTX technique alone. All cases showed the same breakpoints at subbands 9q34.1 and 22q11.2. In CML, it was possible to further define the breakpoint of chromosome 22 to subband q11.21.

Incomplete trisomy 22. I. Familial 11/22 translocation with 3:1 meiotic disjunction. Delineation of a common clinical picture and report of nine new cases from six families

A syndrome due to 3:1 meiotic segregation of balanced 11/22 translocation is defined from nine personally observed patients and 22 cases from the literature with apparently the same aberration. Frequent findings include a characteristic face with deep-set eyes, flat nose, prominent upper lip, receding mandible and preauricular pits or tags, male genital hypoplasia, anal atresia or other anomalies of the anus, cleft palate, and congenital heart defect. Less frequent are severe reduction of the auricles, an additional pair of ribs, and hypoplasia of the diaphragm. Perinatal mortality is high. Growth is usually and psychomotor development is invariably and severely delayed. Balanced 11/22 translocations are apparently disproportionally frequent; as the balanced rearrangement is not easy to detect, it is important to be aware of it at the family investigation of cases with extra chromosomes similar to a No. 22 or 22q-. The unbalanced products are most probably trisomic for both a segment of 22 (22q-) and a distal segment of 11q; the exact determination of the breakpoints is not possible at present due to the similar banding characteristics of the two segments involved in the translocation.

Cytogenetic analysis on eight human breast tumor cell lines: high frequencies of 1q, 11q and HeLa-like marker chromosomes

The chromosomal constitution of 8 human breast tumor cell lines has been analyzed by conventional staining and G-banding methods. The stem line number was established in each case. In all cell lines, a large number of marker chromosomes have been identified. In addition to the 1q marker chromosome, previously reported to be present in several breast tumors from this laboratory, we also found marker chromosomes involving the 11q segment in all 8 cases, and markers resembling some of those found in the Hela cells in 6 out of 8 lines. It appears that the primary genetic (and cytogenetic) changes are specific for each type of target cell and are not shared by other neoplasms. Marker chromosomes found in different types of tumors may represent genetic changes associated with cancer progression, which may be the result of a multitude of genetic alterations.

Heteromorphisms of the Philadelphia (Ph1) chromosome in patients with chronic melogenous leukaemia (CML). I. Classification and clinical significance

In patients with chronic myelogenous leukaemia (CML), we have found the break points on the long arm of chromosome 22 (22q) are variable (heteromorphic or polymorphic). Consequently, the Philadelphia (Ph1) chromosome is heteromorphic in size for the long arm. Based upon the break points and the relative size of chromosome 22, four types of Ph1 chromosomes are proposed. They are: Types I (very large), II (large), III (average) and IV (small) with the break points at bands 22q13.3, 22q13.1, 22q12 and 22q11.3, respectively. The break points are arbitrary and should not be considered absolute since they are based on length differences. In two cases the Ph1 chromosome involved a translocation between chromosome 9 and 22, and the other two cases chromosome 1 or 12. Because Types I and II are hard to recognize by conventional techniques, the RFA technique (R. band by fluorescence with acridine orange) must be performed on all cases. An earlier contention that only chromosome 22 band 12 is concerned with abnormal myeloid cell proliferation in human leukaemia is rejected. Furthermore, break points are not restricted at the junction of 22ql and q2 and 22q2 and q3 and can happen anywhere on the long arm of chromosome 22.

New complex Ph' translocation t (10; 14; 22) in bone marrow cells and in PHA-stimulated peripheral blood cultures in chronic myelocytic leukaemia

A patient with chronic myelocytic leukaemia (CML) and a new complex Philadelphia chromosome (Ph') translocation, t (10; 14; 22), is described. This three way Ph' translocation not involving chromosome 9 was present in the majority of the bone marrow cells, as well as in a great proportion of metaphases from phytohaemagglutinin (PHA) stimulated peripheral blood cultures. The possibility that the Ph' translocation was present also in lymphocytes is discussed and at this regard the involvement of chromosome 14 is of interest considering the documented non random involvement of chromosome 14 in lymphoid malignancies.

Nonrandom chromosome rearrangements in 27 cases of human myeloid leukemia

The R-banding pattern of the chromosomes of 31 patients hospitalized in the Hematologic Clinic for myeloid leukemia were studied before chemotherapy. This analysis permitted identification of one unusual 3-chromosome rearrangement t(3;9;22) in addition to 25 classic forms of (22q-;9q+) translocation accompanied by the specific Ph' chromosome in chronic granulocytic leukemia patients, independent of the blastic course of the disease. During blastic crisis observed in 6 patients, extra 8 and 10 chromosomes, monosomy for chromosome 17, isochromosomes 17q, translocation (12q;13q), and additional Ph' were noted. The nonrandomness of these findings is determined from results published by other authors. Their significance for the cellular phenotype is presently unknown.

Variation in the Philadelphia chromosome

Cytogenetic study of 17 cases of chronic myeloid leukaemia has shown that the Philadelphia chromosome is a variable entity, differing in size and banding pattern between individuals.

Hematopoietic engraftment following transplantation of bone marrow cells carrying a Philadelphia (Ph')-like chromosome

A phenotypically normal donor for bone marrow transplantation was found to have a previously unreported karyotype, 46, XY, t(18q+;22q-), resulting in a Ph'-like chromosome. Identification of the Ph'-like chromosome in cultures of skin fibroblasts, phytohemaglutinin-stimulated peripheral blood cells, and bone marrow cells from the marrow donor, but not in cell cultures from siblings or parents, indicated that it represented an acquired somatic mutation. Demonstration of the Ph'-like chromosome in the marrow graft recipient's blood and bone marrow cells after transplantation provided a unique and definitive marker of engraftment. Hematopoiesis appeared normal in both the donor and recipient after transplantation. This study indicates that a mutation creating a Ph'-like chromosome in hematopoietic cells need not produce hematologic abnormality. Presence of this translocation did not appear to interfere with normal hematopoietic or lymphoid differentiation and replication in the transplant setting.