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S K Ma

Publications and source records attributed to S K Ma.

At least 37 records · Page 2Linked to original sources
PubMed2003

Aberrant p15 gene promoter methylation in therapy-related myelodysplastic syndrome and acute myeloid leukaemia: clinicopathological and karyotypic associations.

Seventeen patients with therapy-related myelodysplastic syndrome/acute myeloid leukaemia (t-MDS/AML) were examined for aberrant p15 gene methylation by methylation-specific polymerase chain reaction. Ten patients (58%) showed p15 methylation, which was significantly related to monosomy/deletion of chromosome 7q, but not to antecedent chemotherapy, blast count, leukaemic evolution or survival. In three of six patients with marrow samples obtained prior to the diagnosis of t-MDS/AML, p15 methylation predated disease development by up to 2 years. Bone marrow transplantation led to the disappearance of p15 methylation in one patient. These results showed that p15 methylation was an early event in the evolution of some t-MDS/AML patients.

Acute Disease↗
PubMed2003

Concurrent mediastinal B cell lymphoma and chronic myeloid leukemia with an unusually favorable response to chemotherapy.

A 67-year-old Chinese woman presented with mediastinal B cell lymphoma in 1992 with incidental leukocytosis. Bone marrow and peripheral blood findings confirmed the diagnosis of chronic myeloid leukemia (CML). After combination chemotherapy and radiotherapy for lymphoma, her peripheral blood counts remained normal, and she refused further treatment for nearly six years. Frank hematologic relapse occurred in 1998 and low dose hydroxyurea was used, which was stopped after six months owing to cytopenia. She remained well without treatment at 12-year follow up. Retrospective Southern blot analysis confirmed BCR gene rearrangement in marrow in 1992 and 1998, but not in the lymphoma or the latest peripheral blood. Fluorescence in-situ hybridzation analysis showed no Philadelphia chromosome positive (Ph+) cells in the peripheral blood at last (FISH) follow-up, but BCR/ABL remained detectable. The relevance of the concomitant occurrence of CML and lymphoma and the unusually favorable response of CML to chemotherapy to the pathogenesis of CML is discussed.

Aged↗
PubMed2003

The occurrence of Philadelphia chromosome (Ph) negative leukemia after hematopoietic stem cell transplantation for Ph positive chronic myeloid leukemia: implications for disease monitoring and treatment.

Chronic myeloid leukemia (CML) is a clonal neoplastic disorder, characterized by t(9;22)(q34;q11) that results in the formation of the Philadelphia chromosome (Ph) and the BCR/ABL fusion gene. Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative treatment for CML. Much of its therapeutic efficacy is attributed to a graft-versus-leukemia (GVL) effect exerted by donor-derived lymphoid cells against the Ph positive (Ph+) clone. Post-HSCT monitoring by cytogenetic and molecular detection of the Ph+ clone is necessary, so that pre-emptive immunologic or pharmacologic treatment may be administered at an early stage of relapse. However, under rare circumstances a second Ph negative (Ph-) leukemia may evolve post-HSCT. The pathogenetic possibilities included leukemia arising from donor-derived hematopoietic stem cells (HSCs), or transformation of residual recipient-derived Ph- HSCs that have survived the conditioning chemotherapy and radiotherapy. Recipient-derived Ph- leukemia may be related to genetic alterations that precede the onset of CML, or myelotoxic effects of the HSCT conditioning regimen. The diagnosis of Ph- relapses requires detailed investigations by conventional karyotyping, fluorescence in-situ hybridization (FISH), and molecular analysis; as well as chimerism studies that help to document the donor or recipient origin of the leukemia. Although uncommonly reported in the past, Ph- relapses may in fact be more frequent if leukemic relapses post-HSCT are more thoroughly evaluated with these investigations. The recognition of Ph- relapses are important in several ways. Ph- relapses cannot be identified by monitoring investigations targeting the Ph+ clone, so that the early detection of Ph- leukemia is usually not possible. Furthermore, Ph- relapses will not respond to therapeutic strategies effective against the Ph+ CML clone.

Hematopoietic Stem Cell Transplantation↗
PubMed2003

Arsenic trioxide in comparison with chemotherapy and bone marrow transplantation for the treatment of relapsed acute promyelocytic leukaemia.

BACKGROUND: The best overall treatment strategy for patients with acute promyelocytic leukaemia (APL) in relapse with chemotherapy, bone marrow transplantation (BMT) or arsenic trioxide (As(2)O(3)) based therapy remains undefined. PATIENTS AND METHODS: We reviewed the clinical course and treatment outcome of 143 APL cases seen in four major hospitals in Hong Kong over a 10-year period. RESULTS: Complete remission (CR) was attained in 113 cases (79%) with all-trans retinoic acid (ATRA) and chemotherapy. Relapse occurred at a median of 16 months in 54 cases, with a 3-year disease free survival of 56%. Post-relapse treatment was successful in 41 cases (76%), giving an actuarial 3-year overall survival (OS) of 81% from CR1. Three different protocols were used: chemotherapy alone (n = 19), allogeneic BMT (n = 14) and an As(2)O(3)-based regimen (n = 21). Chemotherapy was associated with the highest treatment-related mortality (TRM) at 53%, giving a CR2 rate of 47%. TRM was 36% for BMT. The CR2 rate for the As(2)O(3)-based regimen was 100%, with no TRM. However, 38% of As(2)O(3) treated patients had subsequent relapses, which were further salvaged in 75% by combined As(2)O(3) plus ATRA. The actuarial OS for the three protocols leveled off by 2 years at 82% for As(2)O(3), 43% for BMT and 23% for chemotherapy (P = 0.0004). CONCLUSIONS: Our results suggest that As(2)O(3) may be superior to chemotherapy and BMT for the treatment of APL in relapse.

Adolescent↗
PubMed2003

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.

Adult↗
PubMed2002

Two cases of therapy-related acute promyelocytic leukemia (t-APL) after mantle cell lymphoma and gestational trophoblastic disease.

We report two cases of secondary acute promyelocytic leukemia (APL). One patient presented with concurrent APL and missed abortion 1 year after etoposide-based chemotherapy for gestational trophoblastic disease. A prolonged complete remission was achieved with standard chemotherapy. An elderly man developed APL 1 year after alkylator-based chemotherapy for mantle cell lymphoma (MCL). A complete clinical and molecular remission was obtained with chemotherapy and all- trans retinoic acid, followed by arsenic consolidation. Concomitant molecular relapse of APL and MCL clones was detected at 1 year, both of which responded to oral arsenic therapy. High-dose epipodophyllin is a dose risk for secondary APL, but alkylating agents may also be implicated. For patients with a history of active malignancy and heavy previous chemotherapy exposure, the use of nontoxic arsenic therapy appeared to be effective and prudent.

Adult↗
PubMed2002

Fatal diffuse alveolar damage complicating acute myeloid leukemia with abnormal eosinophils and trisomy X.

We describe a case of acute myeloid leukemia (AML) with abnormal eosinophils in a 44-year-old Chinese woman that was complicated by diffuse alveolar damage (DAD) and pulmonary hemorrhage (PH) shortly after induction chemotherapy. Cytogenetic study of bone marrow cells at diagnosis showed a rare aberration of trisomy X (+X) as the sole acquired karyotypic abnormality. We speculate that tissue damage by cellular constituents of the abnormal eosinophils that were released on cell lysis after chemotherapy might be etiologically linked to the occurrence of fatal pulmonary complications.

Acute Disease↗
PubMed2002

Two balanced and novel chromosomal translocations in myeloid malignancies. characterization by multiplex fluorescence in situ hybridization.

We describe two novel chromosomal translocations in two cases of leukemia in which these translocations were further characterized as the sole acquired karyotypic abnormality by mutliplex fluorescence in situ hybridization (M-FISH). They comprised a case of acute myeloid leukemia with t(6;10)(q21;p12) and a case of chronic myelomonocytic leukemia with t(5;12)(q34;q24). To the best of our knowledge, these two balanced translocations are novel and are hitherto unrecognized in hematologic malignancies. While the clinical and pathogenic significance of these translocations remains to be defined, the present report illustrates that M-FISH technology contributes to the exclusion of subtle or cryptic translocations in sole karyotypic aberrations and the confirmation of novel chromosomal arrangements in neoplastic disorders.

Chromosome Mapping↗
PubMed2002

Glucose-6-phosphate dehydrogenase deficiency and hematopoietic stem cell transplantation.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked hemolytic enzymopathy affecting 3% of Southern Chinese males. Among 275 adult allogeneic hematopoietic stem cell transplantations (SCT), five cases (1.8%) each of donors and recipients were G6PD deficient. Among 107 autologous SCT, four patients (3.7%) were G6PD deficient. All subjects were male, except for two female patients with chronic myeloid leukemia (CML). The incidence of G6PD deficiency in female CML patients was significantly higher than the background female incidence (P = 0.004), but comparable with that in the males (P = 0.664). There was no significant hemolysis or delay in red cell engraftment, and all but one patient converted to donor G6PD screening status. One female patient achieved partial correction of her G6PD status and relapsed at 10 months. We suggest that G6PD deficiency should be tested for in all marrow donors and recipients in susceptible populations. From our data, there is a suggestion of increased clinical incidence of G6PD deficiency in female patients with multi-lineage clonal marrow disorders.

Adolescent↗
PubMed2002

Tyrosine kinase inhibitor STI571 in the treatment of Philadelphia chromosome-positive leukaemia failing myeloablative stem cell transplantation.

Eight patients with Philadelphia chromosome-positive (Ph(+)) leukaemia relapsing from stem cell transplantation (SCT) (one syngeneic and seven allogeneic) were treated with the tyrosine kinase inhibitor STI571. Five patients relapsing as chronic myeloid leukaemia (CML) in chronic phase achieved a complete haematological response, with complete and major cytogenetic responses occurring in four and one cases, respectively. One patient became negative for BCR/ABL in the bone marrow. Three patients relapsed as acute leukaemia (two CML in myeloblastic crisis and one Ph(+) acute lymphoblastic leukaemia), all of whom achieved haematological and cytogenetic responses. One patient also became BCR/ABL negative. However, pancytopenia and graft-versus-host disease led to cessation of treatment in the remaining two cases, which was followed by disease recurrence refractory to further STI treatment. Our results showed that Ph(+) leukaemic relapses after SCT might respond well to STI571 therapy.

Adolescent↗
PubMed2002

Leukaemic relapse of donor origin after allogeneic bone marrow transplantation from a donor who later developed bronchogenic carcinoma.

Donor-derived leukaemia is exceptional after allogeneic bone marrow transplantation (BMT). A woman with chronic myeloid leukaemia received an allogeneic BMT from a human leucocyte antigen-identical brother. The donor, a 50-year-old non-smoker, died of squamous cell bronchogenic carcinoma 1 year later. At 4 years post BMT, the patient became BCR/ABL positive and relapsed with acute myeloid leukaemia, which was shown to be donor-derived cytogenetically and molecularly. Retrospective analysis showed that the donor-leukaemic clone had started to evolve as early as 6 months post BMT. Sequencing of p53 ruled out Li-Fraumeni syndrome. Predisposition to malignancy might be an underlying mechanism of donor-cell leukaemia.

Acute Disease↗
PubMed2002

Clonal marrow abnormalities after azathioprine and sulfasalazine exposure in Crohn's disease: a cautionary tale.

We report a patient with longstanding Crohn's disease (CD) developing recurrent sepsis and impaired neutrophil function tests. His inflammatory bowel disease was controlled with local steroids and sulfasalazine with only short exposure to azathioprine. His blood counts remained within normal range, but the marrow showed mild dysplasia. Repeated cytogenetic examinations revealed trisomies 8 and 9, which are typical for therapy related myelodysplasia. Fluorescent in situ hybridization (FISH) study showed stable persistent trisomies, confined to the myeloid lineage, one year after discontinuation of sulfasalazine. The long-term use of immunodulating agents in patients with CD is not without risks, and early therapy related myelodysplasia might not be easily detected by blood count and morphology assessment alone.

Adult↗
PubMed2002

Subvalvular pulmonary stenosis, demyelination and myelodysplasia with monosomy 7.

We report a 23-year-old male with subvalvular pulmonary stenosis (PS) presenting with concurrent acute demyelinating neuropathy and myelodysplasia with monosomy 7. There was no stigmata of Noonan syndrome or neurofibromatosis, nor any family history of cardiac or hematologic disorders. There are 40 reported pediatric cases of Noonan syndrome with subvalvular PS that developed leukemia, over two-thirds with monosomy 7. There is also a genetic overlap between Noonan syndrome and neurofibromatosis, which is also closely associated with demyelination and leukemia. The importance of recognition of rare clinical syndromes that may predispose to leukemia is discussed.

Adult↗
PubMed2002

Routine screening of (--(SEA)) alpha-thalassemia deletion by an enzyme-linked immunosorbent assay for embryonic zeta-globin chains.

We evaluated an enzyme-linked immunosorbent assay (ELISA) for embryonic zeta-globin chains as a routine screening test for (--(SEA)) alpha-thalassemia deletion (SEA deletion). A total of 174 consecutive patient samples with a request for Hb analysis were recruited. The ELISA method was evaluated against a polymerase chain reaction (PCR)-based technique that was taken as the standard. Among 56 simple carriers of SEA deletion diagnosed by PCR and 112 subjects without the SEA deletion, the sensitivity and specificity of the ELISA method was 89.3-96.4 and 98.2-100%, respectively, depending on the cutoff value for optical density that was adopted. The ELISA method was able to detect both subjects with SEA deletion and concurrent beta-thalassemia trait in this series, but only 1 out of 4 patients (25%) with Hb H disease. We speculate that incomplete lysis of hypochromic microcytic red cells together with the low red cell count in Hb H disease might account for the false-negative results. We showed that the ELISA method for embryonic zeta-chains was a sensitive method of screening for SEA deletion carriers at our locality, and should be easily adopted in a routine diagnostic laboratory. The method was rapid and also amendable to automation. In areas with a high prevalence of alpha-thalassemia, improved detection of SEA deletion carriers would ultimately facilitate the identification of pregnancies at risk of hydrops fetalis and its prevention through prenatal diagnosis.

Adolescent↗