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C J Harrison

Publications and source records attributed to C J Harrison.

At least 55 records · Page 3Linked to original sources
PubMed2000

t(7;12)(q36;p13), a new recurrent translocation involving ETV6 in infant leukemia.

The ETV6 gene is rearranged as a result of translocations involving a wide variety of chromosomal partners. To date, 12 partner genes for ETV6 have been cloned, and a further 23 chromosomal regions have been described. We previously identified a cryptic t(7;12) with ETV6 involvement in two cases of infant leukemia. The finding of a third case of t(7;12), also in an infant, prompted a more focussed search based on the common features found in these patients and those reported in the literature. The selection criteria were age at diagnosis < 20 months and the presence of +19 and/or +8 in the karyotype; cases with abnormalities of 7q and/or 12p were also considered. FISH studies using whole chromosome paints and probes for the ETV6 gene revealed a t(7;12) in 10 out of 23 cases studied. Seven of these had evidence of ETV6 rearrangement. Of those with ETV6 involvement, six had a 7q36 and one a 7q22 breakpoint. Importantly, in three cases the 7q36 breakpoint was within the same PAC, suggesting the existence of a new nonrandom translocation. However, in at least one patient the 7q36 breakpoint was different. The identification of the 7q partner genes will determine whether it is the disruption of ETV6 alone, or the formation of fusion genes, that is important for leukemogenesis in these patients. As both 7q36 and 7q22 are critical regions of gene loss in del(7q) leukemias, the identification of partner genes from these regions may also be important in understanding the pathogenesis of these diseases.

Chromosome Breakage↗
PubMed2000

Monosomy 20 as a pointer to dicentric (9;20) in acute lymphoblastic leukemia.

Twenty new cases of acute lymphoblastic leukemia (ALL) with the dicentric chromosome dic(9;20)(p1113;q11) are presented. This chromosomal abnormality is difficult to identify from G-banding alone. It masquerades as monosomy 20 and is only accurately identified by fluorescence in situ hybridization (FISH). Monosomy 20 was found in 59/2790 patients with successful karyotypes entered to the Leukaemia Research Fund/UK Cancer Cytogenetics Group Karyotype Database in ALL (LRF/UKCCG Karyotype Database). FISH revealed dic(9;20) in 20/25 cases with available material. Extra copies of chromosome 21 were found in 8 of the 20 cases. Patients were 14 females and six males, aged 1-32 years (median 4 years), with leukocyte counts of 2-536 (median 23) x 109/l and immunophenotypes of common or pre-B ALL (17 cases), T-ALL (one case) or unknown (two cases). Four patients relapsed at 2, 22, 28 and 47 months and two died at 49 and 63 months (median follow-up 37 months). FISH studies on the remaining five patients showed one with monosomy 20 and four with other rearrangements of the chromosome. This study has increased the number of reported cases of dic(9;20) from 17 to 37. It has identified dic(9;20) in one case of T-ALL and shows an association of this translocation with trisomy 21.

Adolescent↗
PubMed2000

Analysis of ETV6/AML1 abnormalities in acute lymphoblastic leukaemia: incidence, alternative spliced forms and minimal residual disease value.

The t(12;21)(p13;q22) translocation, resulting in the fusion of the ETV6 and AML1 genes, occurs in 20-25% of paediatric B-lineage acute lymphoblastic leukaemias (ALL). The identification of the fusion product has important prognostic and therapeutic implications as the translocation has been associated with a favourable clinical outcome. The aim of this study was threefold: (i) to assess the frequency and clinical association of the fusion gene in patients with and without a cytogenetically detectable chromosome 12 and/or 21 abnormality or failed cytogenetic results, (ii) to characterize alternative forms of ETV6/AML1 transcripts, and (iii) to use ETV6/AML1 as a molecular marker for the investigation of minimal residual disease (MRD). ETV6/AML1 fusion was detected in 22 (39%) of 56 cases studied by reverse transcriptase polymerase chain reaction (RT-PCR). ETV6/AML1 fusion was found in nine out of 16 (56%) cases with a cytogenetically visible chromosome 12 abnormality, but also in nine out of 29 patients (31%) without a chromosome 12 abnormality or patients with failed cytogenetics (four out of 11 patients, 36%), making this the most common cytogenetic abnormality in childhood ALL. Alternatively spliced ETV6/AML1 forms were investigated in 14 of the positive patients. Exon 5 of ETV6 was fused in frame to all AML1 exons, except exon 4. Fusion to exon 6 of AML1 resulted in one amino acid change. The presence of ETV6/AML1 was associated with a lower white blood cell count (Student's t-test; P = 0.009) and common (c)ALL phenotype (chi(2) test; P > 0.001), but no better disease-free survival. Our study shows that (i) RT-PCR is the most effective approach for the detection of t(12;21) in childhood ALL, (ii) the association of ETV6/AML1 and chromosome 12 and/or 21, seen in 56% of our cases, further confirms existing data, (iii) overall survival of patients with t(12;21) was not better than other cytogenetics groups, and (d) MRD analysis using ETV6/AML1 fusion is specific, but not sensitive enough to avoid false negative results.

Adolescent↗
PubMed2000

The genetics of childhood acute lymphoblastic leukaemia.

In childhood acute lymphoblastic leukaemia (ALL) a number of genetic changes have been identified which provide diagnostic and prognostic information with a direct impact on patient management. The most significant abnormalities include the translocation, t(12;21)(p13;q22), giving rise to the ETV6/AML1 gene fusion; BCR/ABL arising from t(9;22)(q34;q11); re-arrangements of the MLL gene; the E2A/PBX1 from the t(1;19)(q23;p13); re-arrangements of MYC with the immunoglobulin genes and re-arrangements of the T cell receptor genes. Chromosomal deletions, particularly those of the short arms of chromosomes 9 and 12 and the long arm of chromosome 6, have been postulated to be the sites of tumour suppressor genes (TSG). Numerical chromosomal abnormalities are of particular importance in relation to prognosis. High hyperdiploidy (50-65 chromosomes) is associated with a good risk, whereas the outlook for patients with near haploidy (23-29 chromosomes) is extremely poor. In view of the introduction of risk-adjusted therapy into the UK childhood ALL treatment trials, an interphase FISH screening programme has been developed to reveal chromosomal abnormalities with prognostic significance in childhood ALL.

Child↗
PubMed2000

The rug3 locus of pea encodes plastidial phosphoglucomutase.

Two cDNA clones were isolated from pea (Pisum sativum L.) and their deduced amino acid sequences shown to have significant homology to phosphoglucomutases from eukaryotic and prokaryotic sources. The longer cDNA contained a putative transit-peptide-encoding sequence, supporting the hypothesis that the isolated clones represent the cytosolic and plastidial isoforms of phosphoglucomutase in pea. Plastid protein import assays confirmed that the putative plastidial isoform was targeted to the plastid stroma where it was proteolytically processed. Expression, co-segregation, linkage, and molecular analyses have confirmed that the rug3 locus of pea encodes plastidial phosphoglucomutase. Mutations at this locus result in a near-starchless phenotype of the plant.

Amino Acid Sequence↗
PubMed2000

Correlation of maternal and pup NK-like activity and TNF responses against cytomegalovirus to pregnancy outcome in inbred guinea pigs.

Immunologic causes for poor outcome of pregnancy complicated by primary cytomegalovirus (CMV) infection are only partially understood. Maternal and pup tumor necrosis factor (TNF) and natural killer cell (NK)-like activity associated with primary gestational CMV infection initiated in either the first or third trimester equivalent in the inbred guinea pig model were investigated. Poor pregnancy outcome defined as fetal resorptions, premature delivery, stillbirths, and intrauterine growth retardation occurred with infection at either gestational time. Induction of TNF and NK activity by CMV infection during pregnancy correlated with resorptions in early pregnancy infection and with premature labor in late pregnancy infection. Stillbirths occurred with CMV infection at either time. Regardless of the gestational time of CMV acquisition, poor outcome correlated with higher maternal NK and TNF responses during the first weeks after maternal virus acquisition. Furthermore, CMV infected dams with loss of >/= 50% of conceptus had higher TNF responses than infected dams with < 50% conceptus loss. Likewise, pups born in litters from CMV-infected dams with resorptions and/or premature labor also had enhanced NK activity and TNF response to CMV compared with pups born to dams not having resorptions or premature labor. TNF responses in the delivered pups of infected dams were higher than from pups of uninfected dams regardless of litter outcome, whereas pup NK responses were enhanced only in pups from litters of dams with premature labor or resorptions. Enhanced NK and TNF activity appear to be associated with premature delivery and other poor outcomes of pregnancy.

Animals↗
PubMed2000

Antivirals other than for HIV therapy.

This review concentrates on drugs directed at viruses other than HIV and does not include anti-HIV drugs. Many antivirals are nucleoside analogues, although new classes of enzyme inhibitors are being developed for treatment of HIV (proteases) and enteroviruses. Antisense drugs and receptor blockers have recently been approved. Regardless of mechanism, antivirals are predominantly virustatic, not virucidal, and usually require help from the host immune system to either completely eliminate pathogens (e.g., influenza) or to provide sufficient immune surveillance to prevent a latent pathogen from reactivating (e.g., the herpesviruses). Viruses by nature are intracellular pathogens, using the host cell to produce progeny. Often the viral pathogen uses the host cell machinery or enzyme system to facilitate replication. At times the virus usurps nearly the entire intracellular system for replication and may shut down all functional host cell output for host-determined products. Because of the intracellular nature of viruses and because viruses use many "normal" host cell factors, functions, and systems for replication, antivirals can have notable toxicities to host cells. As antivirals inhibit viral activity in the viral-infected host cells (these encompass a minority of the total host cell numbers), they may also negatively affect functions in the virus-uninfected host cells. These alterations may be biochemical, detected only if sought specifically, or clinically obvious toxicities. Either may limit the use of some antivirals to severe or life-threatening situations.

Antiviral Agents↗
PubMed1999

Fluorescence in situ hybridization analysis of masked (8;21)(q22;q22) translocations.

The translocation (8;21)(q22;q22) is associated with acute myeloblastic leukemia (AML M2). The accurate detection of this chromosomal rearrangement is vital due to its association with a favorable prognosis. Variant translocations exist; these may be hidden within an unusual or complex karyotype. In such cases, it is often difficult to confirm the presence of t(8;21)(q22;q22) by conventional cytogenetic analysis alone. The molecular detection of the AML1/ETO fusion gene is possible by reverse transcriptase polymerase chain reaction (RT-PCR) or dual-color fluorescence in situ hybridization (FISH) using probes specific for AML1 and ETO. Four cases of AML M2, with unusual or complex structural chromosomal abnormalities, without cytogenetic evidence of the classical t(8;21)(q22;q22), were studied by FISH. Two were AML1/ETO positive by RT-PCR, one showed a rearrangement by AML1 by Southern analysis, and the fourth had morphological features characteristic of t(8;21). The FISH results showed a co-localization of one AML1 and one ETO signal in interphase and metaphase nuclei in all four cases, demonstrating the presence of variant t(8;21)(q22;q22) rearrangements. Therefore, FISH analysis with the AML1 and ETO probes is extremely valuable, in cases of AML M2, because of its ability to reveal masked t(8;21)(q22;q22) translocations and thus quickly confirm the diagnosis, allowing patients to be assigned to the correct risk group in terms of treatment.

Adult↗
PubMed1999

Investigation of clonal involvement of myeloid cells in Philadelphia-positive and high hyperdiploid acute lymphoblastic leukemia.

Acute lymphoblastic leukemia (ALL) with a high hyperdiploid clone has a good prognosis for both childhood and adult patients while patients with Philadelphia-positive (Ph) ALL do badly at all age groups. It has been suggested that different responses to treatment might be related to the cell of origin of the leukemia with 'stem cell' cases responding less well than those arising in a lymphoid committed progenitor cell. The clonal involvement of different cell lineages in 12 patients with acute lymphoblastic leukemia has been examined by applying fluorescence in situ hybridization (FISH) to detect chromosomal abnormalities in bone marrow cells previously identified by morphology and/or immunology. The karyotype of the malignant clone was either high hyperdiploid or Philadelphia translocation (Ph) positive with a breakpoint in the minor breakpoint cluster region of the BCRgene (m-BCR) or in the major breakpoint cluster region of the BCR gene (M-BCR). The high hyperdiploid clone, in each case, was found in cells of the B-lymphoid (CD19+) lineage but not in T cells (CD3+) or in cells of the myeloid (CD13+) or erythroid (glycophorin A+) lineages, indicative of a lymphoid committed progenitor cell. Heterogeneity of lineage involvement was found in Ph+ ALL: the m-BCR Ph+ clone was found in lymphoid/blast cells but not in neutrophils or eosinophils. In contrast both M-BCR Ph+ clones were detected in myeloid as well as lymphoid lineages, indicative of a stem cell origin.

Adolescent↗
PubMed1999

Abnormal cytogenetic clones in patients with aplastic anaemia: response to immunosuppressive therapy.

We report the response to immunosuppressive therapy with antithymocyte globulin (ATG) and cyclosporin or oxymetholone in 13 cases of aplastic anaemia (AA) with an abnormal cytogenetic clone detected at or sometime after diagnosis. Blood and bone marrow examination showed no distinctive morphological features of myelodysplasia (MDS) at diagnosis. Haematological response occurred promptly in eight cases; the remainder responded after additional immunosuppression with or without oxymetholone. Three patients had a late relapse of AA, treated successfully by allogeneic bone marrow transplantation in one; the others responded to oxymetholone. Transformation to MDS or acute leukaemia was not observed after a median follow-up of 4.1 years (range 1.2-11.2). In four patients the cytogenetic clone disappeared after treatment.

Adult↗
PubMed1999

A simple, robust, validated and highly predictive index for the determination of risk-directed therapy in acute myeloid leukaemia derived from the MRC AML 10 trial. United Kingdom Medical Research Council's Adult and Childhood Leukaemia Working Parties.

Data on 1711 patients, aged up to 55 years, in the MRC AML 10 trial were used to create a prognostic index for use in risk-directed therapy decision making for younger patients with acute myeloid leukaemia (AML). Two parameters, response after course 1 and cytogenetics, were strongly predictive of outcome. For patients with complete remission, partial remission and resistant disease, 5-year survival from the start of course 2 was 53%, 44% and 22% and relapse rates were 46%, 48% and 69% respectively, and for patients with favourable, intermediate and adverse karyotypic abnormalities, survival was 72%, 43% and 17% and relapse rates were 34%, 51% and 75% respectively (all P < 0.0001). Patients with FAB type M3 but no cytogenetic t(15;17) also had a low relapse rate (29%). These three factors were combined to give three risk groups: good (favourable karyotype or M3, irrespective of response status or presence of additional abnormalities), standard (neither good nor poor), poor (adverse karyotype or resistant disease, and no good-risk features). Survival for these three groups was 70%, 48% and 15% respectively and relapse rates were 33%. 50% and 78% (both P < 0.0001). The index is simple (based on just three parameters), robust (derived from 1711 patients), highly discriminatory (55% survival difference between good and poor risk) and validated, so can be applied in the clinical setting to assist with therapeutic decisions as in the current AML 12 trial.

Acute Disease↗
PubMed1998

The importance of cytogenetics and associated molecular techniques in the management of patients with leukaemia.

The cytogenetic analysis of haematological malignancies plays a major role in diagnosis. A large number of non-random chromosomal abnormalities are associated with specific types of leukaemia. Often, the cytogenetic result provides the definitive diagnosis. The recent developments in molecular cytogenetic technologies, in association with conventional cytogenetic analysis, have improved the accuracy of the results and led to the finding of new chromosomal abnormalities in leukaemia. Patients may be monitored by cytogenetics, molecular techniques and/or fluorescence in situ hybridization (FISH) during the course of their management, for evidence of minimal residual disease. These techniques also provide a useful method for monitoring patients following bone marrow transplantation, particularly when the patient and the donor are of the opposite sex. The cytogenetic result is an independent prognostic indicator, with certain karyotypes associated with a good prognosis, although others indicate a poor outcome.

Bone Marrow Transplantation↗
PubMed1998

Ten novel 11q23 chromosomal partner sites. European 11q23 Workshop participants.

The MLL gene located at 11q23 has been described as a 'promiscuous' gene due its involvement with a large number of genetic partners. The EU Concerted Action Workshop on 11q23 provided 550 cases for study of which 82 showed abnormalities which did not involve the established translocations or deletion of 11q23. In these 'other' cases, which included inversions and duplications, 11q23 was found to be involved with 25 chromosome partners of which 10 had not been previously reported. These were 1q31, 4p11, 6q13, 8q21, 10q22, 10q25, 11q11, 11q21, 13q34 and 18q23. This study demonstrated the value of the Workshop, in confirming the diversity of chromosomal partner sites involved with 11q23 and in the identification of new partners.

Acute Disease↗
PubMed1998

Abnormalities of the ETV6 gene occur in the majority of patients with aberrations of the short arm of chromosome 12: a combined PCR and Southern blotting analysis.

Involvement of the ETV6 gene, located at 12p13, has been investigated in 20 patients with an abnormality of the short arm of chromosome 12 (abn 12p) detected cytogenetically. Patients in the study had c/pre-B acute lymphoblastic leukemia (ALL) (nine children and three adults), T-ALL (three adults), acute myeloid leukemia (AML) (two adults), biphenotypic acute leukemia (Bip-L) (one adult), myelodysplasia (MDS) (one adult) and chronic myelomonocytic leukemia (CMML) (one child). Abnormalities of 12p comprised deleted (del)(12p) alone (seven cases), add(12p) alone (seven cases), del(12p) and add(12p) (one case) and balanced translocations of 12p to 1p13, 1q31, 10q11, 14q11 and 15q15 (one case of each). A novel, exon-specific RT-PCR assay identified breakpoints in ETV6 in nine of 19 cases, and showed breakpoints in intron 5 (seven cases of children with c-ALL), in intron 4 (in one adult with Bip-L) and in intron 2 (in one adult with AML). RT-PCR for the ETV6/AMLI fusion (tested in 19 cases) was positive using standard primers in five cases (four of which had shown rearrangements in intron 5) and occurred as a variant fusion in a sixth case (also positive for a rearrangement in intron 5) using 3' RACE PCR. Southern blotting confirmed rearrangements in intron 5 in the five cases available for analysis and revealed a rearrangement in intron 5 in one of 10 cases with no evidence of intron 5 involvement by RT-PCR. Rearrangements in intron 5 of ETV6 were found in eight of nine cases of children with c-ALL of which six carried the ETV6/AMLI fusion. Heterozygosity within intron 5 (revealed by the genomic probe B1) was found in seven of 11 cases tested. Deletion of one allele was indicated in three cases with del(12p) and one case with add(12p). This study, using a combination of ETV6 exon-specific RT-PCR, RT-PCR for ETV6/AMLI and Southern blotting has shown that rearrangement and/or deletion of ETV6 may occur in up to 70% of patients with abn 12p. Furthermore, 90% of children in this study with an abn 12p and c-ALL, carried a rearrangement of ETV6 in intron 5.

Adolescent↗