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M P Link

Publications and source records attributed to M P Link.

At least 37 records · Page 2Linked to original sources
PubMed1997

Case-control study suggests a favorable impact of TEL rearrangement in patients with B-lineage acute lymphoblastic leukemia treated with antimetabolite-based therapy: a Pediatric Oncology Group study.

TEL gene rearrangement is the most common genetic lesion in pediatric acute lymphoblastic leukemia (ALL), occurring in about 25% of B-lineage cases. We previously showed that, among patients treated on St Jude protocols, TEL rearrangement independently conferred an excellent prognosis. To extend these results to patients treated with antimetabolite-based therapy, we performed Southern blot analysis to determine the TEL gene status of 104 cases of B-lineage ALL treated on Pediatric Oncology Group 8602, matched on age, gender, and leukocyte count. There were 52 failures among the 77 patients with germline TEL, compared with only 8 failures among 27 patients in the rearranged group. Based on a two-sided logistic regression analysis, stratified for age (subdivided at 10 years), leukocyte count (subdivided at 50,000), and gender, the estimated odds of failing by 4 years in the germline TEL group is 5.4 times that of the rearranged TEL group, with 95% confidence from 1.9 to 15.6, two-sided P = .0009. Thus, the presence of a rearranged TEL gene is also associated with an improved survival among patients treated with antimetabolite-based therapy. Our results indicate that all newly diagnosed ALL patients should be screened for TEL gene rearrangements and suggest that these patients are candidates for less intensive therapy.

Antimetabolites, Antineoplastic↗
PubMed1997

Fractionated cylophosphamide and back to back high dose methotrexate and cytosine arabinoside improves outcome in patients with stage III high grade small non-cleaved cell lymphomas (SNCCL): a randomized trial of the Pediatric Oncology Group.

BACKGROUND: The Pediatric Oncology Group (POG) conducted a two-arm, randomized study for the treatment of children and adolescents with stage III small, non-cleaved cell lymphoma (SNCCL). Regimen A, based on the group's previous best treatment for this group of patients, included cyclophosphamide (CTX) and high-dose methotrexate (MTX), as well as vincristine (VCR), prednisone (PRED), and intrathecal (IT) chemoprophylaxis. Regimen B, based on a single institution pilot study (Total B therapy), consisted of two rapidly alternating chemotherapy combinations (CTX, VCR, doxorubicin; MTX, and cytarabine (Ara-C) plus coordinated IT chemotherapy. PROCEDURE: One hundred thirty-four consecutive patients were entered on this study. Seventy patients were randomized to Regimen A, and 64 patients to Regimen B. One hundred and twenty-two patients are eligible for response. RESULTS: Complete remission (CR) was achieved by 81% (52/64) of patients on Regimen A, and 95% (55/58) of patients on Regimen B (p=0.014 one-sided). The two-year event-free survival (EFS) is 64% (SE=6%) on Regimen A, and 79% (SE=6%) on Regimen B (p=0.027 by one-sided logrank test). No patient has relapsed on either regimen after a year from diagnosis, although one patient had a second malignancy at day 371. Severe, but manageable, hematologic toxicity was seen in the majority of patients on both regimens, but was more frequent on Regimen B. CONCLUSIONS: We conclude that the cure rate in stage III SNCCL is significantly improved with the use of a short, six-month chemotherapy regimen of fractionated CTX alternated with coordinated MTX and Ara-C. Results suggest that drug schedule, not simple drug selection, influences outcome.

Adolescent↗
PubMed1997

Lack of ETV6 (TEL) gene rearrangements or p16INK4A/p15INK4B homozygous gene deletions in infant acute lymphoblastic leukemia.

Acute lymphoblastic leukemia (ALL) occurring in infants less than 1 year of age differs clinically and biologically from that observed in older children. Cytogenetically, 11q23 translocations are detected in approximately 50% of infant ALLs and fuse the 11q23 gene HRX with a variety of partner chromosomal loci. Overall, HRX rearrangements are detected molecularly in 70-80% of infant ALLs as compared to 5-7% of ALLs arising in older children. Two recently described molecular abnormalities in childhood ALL are ETV6 gene rearrangements and homozygous deletions of p16(INK4A) and/or p15(INK4B). Each of these abnormalities occurs in 15-20% of all childhood ALLs, and neither can be accurately identified by routine cytogenetic analyses. The incidence of these genetic abnormalities and their potential relationship to HRX gene status in infant ALL is unknown. Using Southern blot analyses, we determined ETV6 and p16(INK4A)/p15(INK4B) gene status in a cohort of infant ALLs. No ETV6 rearrangements or homozygous deletions (n=69) or homozygous p16(INK4A) and/or p15(INK4B) gene deletions (n=54) were detected in any of the infant ALLs. Therefore, ETV6 and p16(INK4A)/p15(INK4B) do not play a significant role in the pathogenesis of infant ALL, further emphasizing the distinctive biology of this subset of leukemias.

Carrier Proteins↗
PubMed1997

Altered expression of p53 and mdm-2 proteins at diagnosis is associated with early treatment failure in childhood acute lymphoblastic leukemia.

PURPOSE: To determine whether potential alteration in p53 function through p53 gene mutation or mdm-2 overexpression correlates with early treatment failure in childhood acute lymphoblastic leukemia (ALL). PATIENTS AND METHODS: Diagnostic marrow samples from 34 children were analyzed for p53 gene alterations by western blot and SSCP/DNA sequence analysis and for mdm-2 overexpression by western blot analysis. These samples were derived from two groups of children with ALL: 17 good outcome patients who are in long-term continuous complete remission and 17 poor outcome patients who did not achieve a complete remission or relapsed within 6 months of achieving remission. RESULTS: Two children within the poor outcome group were found to have p53 gene mutations. Furthermore, five poor outcome patients were shown to have greater than 10-fold overexpression of mdm-2 protein compared with the mean level of mdm-2 protein measured in the good outcome group. Aberrant p53 protein expression was found in only one good outcome patient, whereas no good outcome children were found to have elevated levels (> 10-fold) of mdm-2 protein. CONCLUSION: We show for the first time that potential alteration in p53 function in childhood ALL is more common (P = .036) in cases of early treatment failure than in children who remain in long-term continuous remission.

Child↗
PubMed1997

Use of an anti-ALK antibody in the characterization of anaplastic large-cell lymphoma of childhood.

BACKGROUND: Anaplastic lymphoma kinase (ALK) is a tyrosine kinase inappropriately expressed in lymphoid tissue involved by CD30+ anaplastic large-cell lymphoma (ALCL) with the translocation t(2;5)(p23;q35)(, which juxtaposes the nucleophosmin gene (NPM) with that encoding ALK, resulting in a hybrid (NPM-ALK) message. PATIENTS AND METHODS: A polyclonal antibody against residues of the kinase portion of NPM-ALK (designated anti-ALK 11) was tested for clinical utility in paraffin sections of 44 cases of pediatric large-cell lymphoma (LCL) and 17 additional lymphoma cases, by streptavidin-biotin-alkaline phosphatase method. RESULTS: Nineteen of 20 CD30+ cases (the majority exhibiting anaplastic morphology) labeled with anti-ALK 11, and 5/28 CD30- cases were also ALK+ (3 T cells, 1 null cell, and 1 B cell). Sixteen of 17 B-cell pediatric LCLs were negative, as were 6/6 cases of Hodgkin's disease and 7/7 cases of adult B-cell lymphoma. In pediatric LCLs with adequate follow-up (24/44 ALK+), there was no significant association between ALK expression and two-year event-free survival, similar to the finding reported previously for CD30 expression in these cases. CONCLUSION: We conclude that the majority of pediatric CD30+ ALCLs show ALK overexpression, consistent with the presence of the t(2;5)-encoded NPM-ALK fusion, but that the clinical significance of this entity remains unproven.

Adult↗
PubMed1996

High incidence of potential p53 inactivation in poor outcome childhood acute lymphoblastic leukemia at diagnosis.

Previous studies have indicated that p53 gene mutations were an uncommon event in acute lymphoblastic leukemia (ALL) in children. In one series of 330 patients, p53 mutations were seen in fewer than 3%. We analyzed bone marrow mononuclear cells derived from 10 children with ALL at diagnosis who subsequently failed to achieve a complete remission or who developed relapse within 6 months of attaining complete remission for p53 gene mutations and mdm-2 overexpression. We found that three children had p53 gene mutations, and four overexpressed mdm-2. Also, experiments comparing relative levels of mdm-2 RNA and protein in these patients demonstrated that mdm-2 overexpression can occur at the transcriptional and posttranscriptional level in primary leukemic cells. Although we were unable to link Waf-1 RNA expression with p53 status in childhood ALL, our data show potential p53 inactivation by multiple mechanisms in a large percentage of these patients and demonstrate that these alterations can be detected at diagnosis. Inactivation of the p53 pathway may, therefore, be important in children with ALL who fail to respond to treatment and may be useful for the early identification of children requiring alternative therapies.

Adolescent↗
PubMed1995

Treatment of osteosarcoma with ifosfamide: comparison of response in pediatric patients with recurrent disease versus patients previously untreated: a Pediatric Oncology Group study.

This study was designed to test if the activity of a phase II agent, ifosfamide, would have been underestimated if it was tested exclusively in a population of children and young adults with recurrent osteosarcoma. The response rate to ifosfamide was compared in patients younger than 30 years of age with previously untreated osteosarcoma with metastases at diagnosis and/or unresectable primary tumors (stratum 1) with that of patients with recurrent osteosarcoma following adjuvant chemotherapy who were not previously exposed to ifosfamide (stratum 2). Evaluation of response was conducted 3 weeks after two courses of ifosfamide (2400 mg/m2 x 5 days) were administered 3 weeks apart. Nine of 33 (27%) evaluable patients in stratum 1 responded (1 complete and 8 partial responses) to ifosfamide. Among 30 evaluable patients in stratum 2, only 3 (10%) responded (1 complete and 2 partial responses; P = .04) Both groups of patients received equal doses of ifosfamide and experienced comparable toxicities. Results from this study suggest that the activity of new agents will be underestimated if tested in a population of heavily pretreated patients with recurrent disease. When possible, new chemotherapeutic agents should be tested in patients with a poor prognosis who have not been exposed to chemotherapy.

Adolescent↗
PubMed1995

B-cell lineage confers a favorable outcome among children and adolescents with large-cell lymphoma: a Pediatric Oncology Group study.

PURPOSE: The goal of this study was to assess the immunophenotype of uniformly treated cases of pediatric large-cell non-Hodgkin's lymphoma (NHL) to determine the prognostic importance of B-cell and T-cell lineages and of CD30 positivity. PATIENTS AND METHODS: Sixty-nine patients were analyzed by immunochemistry. All patients were classified histologically, staged in a uniform manner, and treated according to one of two protocols for localized (stage I and II) NHL or advanced (stage III and IV) large-cell NHL. Antibodies included anti-CD45, CD20, CD45Ra, MB-2 (not clustered), CD3, CD45Ro, CD43, CD15, CD30, and CD68. Statistical analysis used the exact conditional chi 2 and Kruskall-Wallace tests for clinical features and the log-rank test to evaluate event-free survival (EFS). RESULTS: Immunophenotypic results demonstrated 25 B-cell, 23 T-cell, and 21 indeterminate lineage. Twenty-seven patients expressed CD30 (17 T-cell and 10 indeterminate lineage), and of these, 22 showed histology of anaplastic large-cell lymphoma (ALCL). B-cell patients were older (P = .018) and showed more favorable survival than patients with T-cell or indeterminate lineage (96% EFS at 3 years, 96% v 67% and 74%, B v T and indeterminate lineage [P = .027]). B-cell lineage was seen more frequently in limited-stage patients, but was also associated with favorable survival when stratified for stage (P = .036). CD30 expression (P = .96) and ALCL histology (P = .90) did not show significant associations with survival. CONCLUSION: We conclude that among pediatric large-cell lymphomas, B-cell lineage is proportionately less frequent than in adults and CD30 antigen-expressing lymphomas are frequent among patients with T-cell and indeterminate lineage. B-cell phenotype tends to occur in older children and is associated with superior survival.

Adolescent↗
PubMed1994

Frequency and prognostic significance of HRX rearrangements in infant acute lymphoblastic leukemia: a Pediatric Oncology Group study.

Chromosome band 11q23, the location of the HRX gene, is a site of recurrent translocations in human malignancies. Infants with acute lymphoblastic leukemia (ALL) commonly have 11q23 translocations and have an especially poor prognosis despite intensive chemotherapy. We analyzed 96 cases of infant ALL treated on three consecutive Pediatric Oncology Group protocols to determine the frequency and prognostic significance of molecular rearrangements of HRX. Overall, 78 cases (81%) had HRX rearrangements detected by Southern blot analysis performed with a single HRX cDNA probe, whereas 18 cases (19%) had germline HRX. Of the 78 cases with HRX rearrangements, only 50 had abnormalities of 11q23 detected cytogenetically. Molecular abnormalities of HRX were associated with early treatment failure and a very poor outcome. Estimated event-free survival for patients with HRX rearrangements was 19% (SE, 7%) at 3 years, compared with 46% (SE, 17%) for patients with germline HRX (P = .033 by the two-sided logrank test). Therefore, infants with ALL and molecular abnormalities of HRX represent a group with an extremely high rate of failure who clearly need innovative or experimental treatment. Furthermore, cytogenetic analysis alone failed to detected 36% of HRX rearrangements, suggesting that molecular analysis be performed on all infants with ALL to identify this group of high-risk patients.

Chromosomes, Human, Pair 11↗
PubMed1994

Hodgkin's disease in the very young.

PURPOSE: A retrospective review of patients with Hodgkin's disease treated at Stanford University Medical Center was undertaken to determine if, within the pediatric population, children < or = 10 years of age have a unique prognosis and response to treatment. METHODS AND MATERIALS: Records of all patients treated for Hodgkin's disease at SUMC between 1961 and 1991 were reviewed. RESULTS: Of 2238 patients with Hodgkin's disease, 91 (4%) were < or = 10 years of age. There is a predominance of male patients (80%) and a higher percentage of mixed cellularity (33%) and lymphocyte predominance (13%) histologies among the very young patients compared to adolescents and adults. The 5 and 10-year survival is 94 +/- 3% and 92 +/- 3%, respectively, for children < or = 10 vs. 93 +/- 2% and 86 +/- 3% for adolescents and 84 +/- 1% and 73 +/- 1% for adults. Five and 10-year freedom from relapse is also higher in the youngest children (88 +/- 4% and 85 +/- 4%, respectively) compared to adolescents (78 +/- 3% and 74 +/- 3%, respectively) and adults (70 +/- 1% and 67 +/- 1%, respectively). Actuarial survival at 25 years for children < or = 10 years is 78%, which is slightly better than for adolescents (67%) and significantly better than for adults (41%) (p = 0.001). Actuarial 25-year freedom from relapse is also significantly better for children < or = 10 (78%) compared to adolescents (74% [p = 0.05]) and adults (65% [p = 0.001]). For all stages of disease, children < or = 10 fare similarly to or slightly better than adolescents and substantially better than adults. For those with Stage I or II disease, survival at 5, 10, and 25 years is 98 +/- 2%, 93 +/- 4% and 73%, respectively, for children aged < or = 10; 98 +/- 1%, 91 +/- 3%, and 79%, respectively, for adolescents and 89 +/- 1%, 80 +/- 1%, and 45%, respectively, for adults. The greatest difference between age groups is seen for Stage III and IV patients. Those aged < or = 10 have an 89 +/- 5% 5 and 10-year survival, and 89% actuarial 25-year survival compared to 87 +/- 4%, 80 +/- 5%, and 28%, respectively, for adolescents and 77 +/- 2%, 64 +/- 2%, and 41%, respectively, for adults. Of patients < or = 10 years of age, 28 (31%) were treated with primary external beam radiotherapy, and 59 (65%) received combined modality therapy consisting of low-dose radiation and chemotherapy. With a median follow-up of 11 years, freedom from relapse is 64% and survival 75% for the radiotherapy group, compared to 97% (p = 0.000) and 93% (p = 0.21) for those treated with combined modality therapy. CONCLUSION: Results indicate that young age is a favorable prognostic factor in Hodgkin's disease. Combined modality therapy has led to improved freedom from relapse and survival rates for all stages of disease and is currently the treatment of choice for the majority of very young children.

Adolescent↗
PubMed1994

Secondary breast cancer in patients presenting with osteosarcoma: possible involvement of germline p53 mutations.

Second malignancies following treatment for osteosarcoma are unusual. Breast cancer occurring in patients with osteosarcoma has been reported following therapeutic chest irradiation. We now report three cases of breast cancer occurring in young women who were successfully treated for osteosarcoma. These women had not received therapeutic chest irradiation and in two of the three women there was no family history of breast cancer. Peripheral blood was available for study from one case. Of import, this case demonstrated a germline mutation in exon 7 of the tumor suppressor gene, p53. The mutation was detected by constant denaturing gradient gel electrophoresis and confirmed by DNA sequencing. In this particular patient, inactivation of the p53 gene may be involved in the development of both the first and second malignancy.

Adult↗
PubMed1994

MIC2 analysis in pediatric lymphomas and leukemias.

Monoclonal antibodies to the glycoprotein product of the MIC2 gene strongly and reliably stain primitive neuroectodermal tumors and Ewing's sarcomas, and are negative in neuroblastomas and most rhabdomyosarcomas. Therefore, these antibodies are helpful in the diagnosis of small round cell tumors of childhood (SRCT). Lymphomas also are in the differential diagnosis of SRCT, but few have been studied with respect to MIC2 protein expression. In the present study we used the 12E7 antibody to assess MIC2 expression in 82 pediatric non-Hodgkin's lymphomas. Forty lymphoblastic, 22 small noncleaved, and 20 large cell lymphomas were studied. Strong immunoreactivity was found in 37 of the 40 (93%) lymphoblastic lymphomas, whereas only one of the 22 (5%) small noncleaved lymphomas was 12E7 positive. Four of the 20 (20%) large cell lymphomas also were immunoreactive. Three 12E7+ lymphoblastic lymphomas were primary in bone and were of B-progenitor lineage; Ewing's sarcoma was included in the initial differential diagnosis of these cases. Evaluation of 125 pediatric acute lymphocytic leukemia (ALL) cases for MIC2 expression showed similar results, with all 36 T-cell ALLs showing strong expression, one of eight B-cell (Burkitt-like) ALLs showing 12E7 expression, and 62 of 81 B-progenitor ALLs showing 12E7 positivity. We conclude that among the SRCTs, MIC2 expression is not limited to Ewing's sarcoma and primitive neuroectodermal tumors, but also shows strong and reliable expression in lymphoblastic lymphomas and related leukemias. MIC2 analysis continues to be helpful in the diagnosis of SRCT, provided that a panel of antibodies is used. In addition, the possibility that MIC2 analysis may aid in the distinction of lymphoblastic lymphomas from small noncleaved lymphomas needs to be further addressed.

12E7 Antigen↗
PubMed1994

Ewing's sarcoma--routine diagnostic utilization of MIC2 analysis: a Pediatric Oncology Group/Children's Cancer Group Intergroup Study.

Ewing's sarcoma and peripheral neuroectodermal tumor (PNET) are small blue cell tumors with no reliable positive diagnostic markers. However, Ewing's sarcoma and PNET recently have been shown to strongly express an antigen determined by the MIC2 gene, whereas other blue cell tumors of childhood for the most part do not. MIC2 analysis therefore offers a distinctive addition to the panel of immunohistochemical stains used to differentiate among small blue cell tumors of childhood, since it represents the first positive marker for Ewing's sarcoma and PNET. This study addresses the reliability of MIC2 analysis using the monoclonal antibody 12E7 on tumors registered in the current Intergroup Ewing's Sarcoma protocol. Of 244 tumors, 221 (91%) showed a diffuse strong membranous pattern. The antibody appears to withstand all the fixation variables inherent in a multi-institutional study. We conclude that MIC2 expression is highly reliable as a positive marker for the Ewing's sarcoma/PNET family of tumors when the results are interpreted in the total context with clinical and pathologic parameters.

12E7 Antigen↗
PubMed1994

ABVD/MOPP and low-dose involved-field radiotherapy in pediatric Hodgkin's disease: the Stanford experience.

PURPOSE: We reported previously that treatment with six cycles of mechlorethamine, vincristine, procarbazine, and prednisone (MOPP) chemotherapy and 15 to 25 Gy irradiation was effective in curing children with Hodgkin's disease, but was associated with a 6.5% 10-year risk of development of secondary leukemia. Based on the results of that study, a successor study was designed with the objective to maintain treatment efficacy while decreasing adverse effects, particularly the occurrence of secondary leukemia. PATIENTS AND METHODS: Fifty-seven children with a chronologic and/or bone age less than 16 years were enrolled onto this study between May 1982 and October 1990. Treatment consisted of six cycles of combination chemotherapy--three of doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) and three of MOPP--and low-dose irradiation (15 Gy) of involved fields. Boosts of 10 Gy were given to areas of bulky disease and to those that did not respond completely after two cycles of chemotherapy. RESULTS: With a median follow-up duration of 6.7 years, the projected 10-year survival and event-free survival (EFS) rates are 96% (SE 2.5%) and 93% (SE 3.5%) for the entire cohort of 57 patients, and 85% (SE 10%) and 69% (SE 12.8%), respectively, for 13 patients with stage IV disease. No patient has developed a second malignancy. Growth and development have progressed normally. No patients have symptomatic cardiac, pulmonary, or thyroid disease. Subclinical abnormalities of pulmonary function were detected in 32% and chemical hypothyroidism in 16%. CONCLUSION: This therapy was highly efficacious in children with Hodgkin's disease without unacceptable toxicity. Future efforts should be directed toward further reducing therapy for favorable early-stage patients and improving treatment efficacy for those with stage IV disease.

Adolescent↗
PubMed1994

Hypnosis in the prevention of chemotherapy-related nausea and vomiting in children: a prospective study.

To study the effectiveness of hypnosis for decreasing antiemetic medication usage and treatment of chemotherapy-related nausea and vomiting in children with cancer, we conducted a prospective, randomized, and controlled single-blind trial in 20 patients receiving chemotherapy for treatment of cancer. Patients were randomized to either hypnosis or standard treatment. The hypnosis group used hypnosis as primary treatment for nausea and vomiting, using antiemetic medication on a supplemental (p.r.n.) basis only, whereas the control group received a standardized antiemetic medication regimen. Nausea, vomiting, and p.r.n. antiemetic medication usage were measured during the first two courses of chemotherapy. Anticipatory nausea and vomiting were assessed at 1 to 2 and 4 to 6 months postdiagnosis. Patients in the hypnosis group used less p.r.n antiemetic medication than control subjects during both the first (p < .04) and second course of chemotherapy (p < .02). The two groups did not differ in severity of nausea and vomiting. The hypnosis group experienced less anticipatory nausea than the control group at 1 to 2 months postdiagnosis (p < .02). Results suggest self-hypnosis is effective for decreasing antiemetic medication usage and for reducing anticipatory nausea during chemotherapy.

Adolescent↗
PubMed1994

Simultaneous expression of RBTN-2 and BCR-ABL oncogenes in a T-ALL with a t(11;14)(p13;q11) and a late-appearing Philadelphia chromosome.

Cytogenetic analysis of a pediatric patient with T-cell acute lymphoblastic leukemia (T-ALL) revealed a mosaic karyotype, 47,XX,+17,t(11;14)(p13;q11)/47,XX,+17,t(9;22)(q34;q11),t(11;14) (p13;q11). DNA blot analysis was used to examine the break-point within the BCR gene on chromosome 22 and showed that the breakpoint occurred within the 20-kb minor breakpoint cluster region (m-bcr) located within the first intron of the BCR gene. Immunoprecipitation analysis demonstrated that the leukemic cells expressed the P185 BCR-ABL protein tyrosine kinase. P185 BCR-ABL has previously been shown to be expressed in most cases of Ph+ acute leukemia of myeloid and B-progenitor origin. Here, we demonstrate for the first time that P185 can also be expressed in the T-cell lineage. DNA blot hybridization was also used to characterize the t(11;14) translocation. This showed rearrangement on chromosome 11 within the T-ALLbcr region, upstream of the RBTN-2 gene. Polymerase chain reaction revealed the presence of RBTN-2 transcripts in the leukemic cells. Finally, comparison of the T-ALLbcr, BCR-ABL, IGH, TCR beta and gamma gene rearrangements in leukemic cells obtained at the time of diagnosis and at first relapse showed that relapse occurred in a leukemic clone indistinguishable from the major Ph+ clone involved at diagnosis. Together, these data support a multistep pathogenesis in which the Philadelphia (Ph) chromosome translocation appeared subsequent to the +17 and t(11;14) and imparted a growth advantage over the Ph-negative cells that carried these abnormalities.

Base Sequence↗
PubMed1993

HRX involvement in de novo and secondary leukemias with diverse chromosome 11q23 abnormalities.

Chromosome band 11q23 is a site of recurrent translocations and interstitial deletions in human leukemias. Recent studies have shown that the 11q23 gene HRX is fused to heterologous genes from chromosomes 4 or 19 after t(4;11)(q21;q23) and t(11;19)(q23;p13) translocations to create fusion genes encoding proteins with structural features of chimeric transcription factors. In this report, we show structural alterations of HRX by conventional Southern blot analyses in 26 of 27 de novo leukemias with cytogenetically diverse 11q23 abnormalities. The sole case that lacked HRX rearrangements was a t(11;17)-acute myeloid leukemia with French-American-British M3-like morphology. We also analyzed 10 secondary leukemias that arose after therapy with topoisomerase II inhibitors and found HRX rearrangements in 7 of 7 with 11q23 translocations, and in 2 of 2 with unsuccessful karyotypes. In total, we observed HRX rearrangements in 35 leukemias involving at least nine distinct donor loci (1q32, 4q21, 6q27, 7p15, 9p21-24, 15q15, 16p13, and two 19p13 sites). All breakpoints localized to an 8-kb region that encompassed exons 5-11 of HRX, suggesting that fusion proteins containing similar portions of HRX may be consistently created in leukemias with 11q23 abnormalities. We conclude that alteration of HRX is a recurrent pathogenetic event in leukemias with 11q23 aberrations involving many potential partners in a variety of settings including acute myeloid leukemia, acute lymphoblastic leukemia, chronic myelogenous leukemia in blast crisis, and topoisomerase II inhibitor-induced secondary leukemias of both the myeloid and lymphoid lineages.

Antineoplastic Agents↗