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Biomedical subjects

C Risueño

Publications and source records attributed to C Risueño.

6 recordsLinked to original sources
PubMed1996

t(1;5)(q23;q33) in a patient with high-risk B-lineage acute lymphoblastic leukemia.

The t(1;5)(q23;q33) is a rare genetic anomaly that was reported previously in two infants with a myeloproliferative disorder and eosinophilia and in one adult patient with acute nonlymphocytic leukemia (ANLL). A 13-year-old boy with high-risk early pre-B acute lymphoblastic leukemia (ALL) who presented to our institution carried the t(1;5)(q23;q33). He had an initial blast count of 230 X 10(9)/L and responded poorly to prednisone. Complete remission (CR) was achieved, and he had a bone marrow (BM) relapse 3 months after despite intensive consolidation therapy. He underwent allogeneic BM transplantation (BMT) from a human leukocyte antigen (HLA)-identical siblings in early relapse with total body irradiation (TBI) and cyclophosphamide conditioning. He had a short second CR with a central nervous system (CNS) relapse on day + 106 after BMT. Two of the previously reported patients also did not respond to chemotherapy. The t(1;5)(q23;q33) appears to be a rare lineage nonspecific anomaly related to hematologic malignancies that are resistant to current therapy.

Adolescent↗
PubMed1995

Rapid intraclonal switch of lineage dominance in congenital leukaemia with a MLL gene rearrangement.

We describe a case of neonatal mixed lineage leukaemia which presented with a dominant B progenitor lymphoblast population plus a minor monocytic component. Treatment of the patient with corticosteroid and Ara-C resulted in loss of lymphoblasts and a rapid (within 7 days) increase and dominance of the monocytic component. The common clonal origin of the two cell types was evident from the identical rearrangement in the MLL gene and a shared rearrangement of one IGH allele. In common with other neonatal or infant ALL with MLL gene rearrangements, this leukaemia may have originated in a common B-monocytic lineage stem cell during foetal haemopoiesis. The observations further suggest that the therapeutic impact of the MLL gene rearrangement is to some extent dependent on the cellular context in which it is expressed.

DNA-Binding Proteins↗
PubMed1993

[Chronic myeloid leukemia: cytogenetic and molecular study and its relationship with the disease course].

The aim of this study was to perform a cytogenetic and molecular study in patients with chronic myelogenous leukemia and to seek a possible relation between bcr gene break points and the clinical evolution of the disease. The cytogenetic study allowed to establish the presence of Ph chromosome and the molecular study localized the break point in bcr region of chromosome 22 using the Southern technique, hybridizing with bcr fragment derived probes bcr1 and bcr2. Forty eight patients were studied, 27 male (aged 46.5 years) and 21 female (aged 56). Forty seven patients were Ph +. A rearrangement in 3' bcr region was found in 25 patients and in 5' region in 23. During the follow up period 20 patients developed a blast crisis or accelerated phase. In 11 of these the rearrangement was in region'3 and their chronic phase lasted a mean of 33.1 months; in 9 the rearrangement was in region 5' and their chronic phase lasted 44.1 months. There were no differences in event-free survival between those with rearrangement in region 3' or 5', however these was a tendency towards a longer chronic phase duration in those with 5' breaks. The lack of correlation between the location of break points and the evolution of the disease may be due to a selection of patients with a better evolution and the exclusion of those with a rapid progression to blast crisis or accelerated phase.

Adult↗
PubMed1992

Molecular epidemiology of Burkitt's lymphoma from South America: differences in breakpoint location and Epstein-Barr virus association from tumors in other world regions.

We have previously shown that the endemic (African) and sporadic (North American) forms of Burkitt's lymphoma (BL) differ at a molecular level. We have now extended our studies to the molecular epidemiology of BL in South America, specifically to two climatic regions: temperate (Argentina and Chile) and tropical (Brazil). We have examined the patterns of chromosomal breakpoint locations in 39 tumors with respect to geography and Epstein-Barr virus (EBV) association. The result of these analyses provide further support for the existence of pathogenetically distinct subtypes of BL in different world regions. The majority of breakpoints on chromosome 8 in South American BL (41%) occurred in the immediate flanking region of c-myc, ie, further 5' of the "typical" sporadic breakpoints, in the first exon/intron region, and further 3' of the "typical" endemic breakpoints, which are usually distant from c-myc. However, the distribution of breakpoints on chromosome 14 in tumors from the temperate and tropical regions of South America is similar to that observed in sporadic and endemic tumors. Interestingly, only one tumor with an unrearranged c-myc gene joined to the S mu region of chromosome 14 was observed. This combination was also rarely observed in our earlier series and presumably is either less readily generated by the mechanism that mediates 8;14 translocation or requires other, infrequent genetic changes to provide the necessary selective advantage for lymphomagenesis. The frequency of EBV association in South American BL (51%) is also intermediate with respect to tumors from the United States (30%) and Africa (100%). No correlation with the breakpoint location on chromosome 8 was discernable. Surprisingly, only 54% of tumors with breakpoint outside c-myc were EBV positive. This is in contrast to endemic tumors and suggests that any pathogenetic contribution of EBV is not dependent on breakpoint location, but is more likely to complement additional pathogenetic elements that differ in different world regions.

Adolescent↗