9p Rearrangements in ALL

1999-08-01   Nyla A Heerema  

1.The Ohio State University, Division of Clinical Pathology, Department of Pathology, 167 Hamilton Hall, 1645 Neil Ave, Columbus, OH 43210, USA

Clinics and Pathology

Disease

acute lymphocycic leukemia (ALL)

Phenotype stem cell origin

lack of specificity for a particular immunophenotype

Epidemiology

approximately 10% of childhood ALL, similar in adult ALL

Prognosis

recent data indicate that an abnormal 9p is an adverse risk factor for B-lineage, but not T-lineage pediatric patients; this is more pronounced in standard-risk patients (age 1 - 9 years with WBC count

Cytogenetics

Cytogenetics morphological

various aberrations result in an abnormal 9p; these include monosomy 9, del(9p), add(9p), der(9)t(V;9)(V;p), dic(V;9)(V;p), i(9q) and balanced translocations with 9p breakpoints; dicentric chromosomes in ALL nearly always involve a chromosome 9; an abnormal 9p usually occurs as part of a more complex karyotype; it occurs as a sole aberration in less than 10% of cases with an abnormal 9p

Additional anomalies

additional anomalies are frequent; an abnormal 12p is particularly frequent (16% of cases), and a deletion of 6q is also frequent (11% of cases)

Genes Involved and Proteins

Note
the different types of 9p aberrations may have different molecular consequences; when a deletion of 9p occurs, the genes involved colud be MTS1/CDK4I/p16INK4A(CDKN2) and MTS2/p15INK4B(CDKN2B); these are believed to be tumor suppressor genes, and loss of heterozygosity occurs more frequently than cytogenetic deletions of 9p; however, mutation of the remaining allele is infrequent, and methylation changes may cause inactivation of the remaining allele

Article Bibliography

Pubmed IDLast YearTitleAuthors

Summary

Atlas Image
del(9p)  G- banding - Courtesy Jean-Luc Lai and Alain Vanderhaegen (left), and, from middle left to right: del(9)(p13), del(9)(p21), and del(9)(p22) - Courtesy Diane H. Norback, Eric B. Johnson, and Sara Morrison-Delap, UW Cytogenetic Services; Hybridization with Vysis CDKN2A/CEP9 probe showing 2 green and 2 red signals on normal and one red signal on metaphase with 9p deletion. u2013 Courtesy Adriana Zamecnikova.

Citation

Nyla A Heerema

9p Rearrangements in ALL

Atlas Genet Cytogenet Oncol Haematol. 1999-08-01

Online version: http://atlasgeneticsoncology.org/haematological/1156/img/js/lib/hgnc