Deletion of 7p or monosomy 7 in pediatric acute lymphoblastic leukemia is an adverse prognostic factor: a report from the Children's Cancer Group

Abstract

Monosomy 7 or deletions of 7q are associated with many myeloid disorders; however, the significance of such abnormalities in childhood acute lymphoblastic leukemia (ALL) is unknown. Among 1880 children with ALL, 75 (4%) had losses involving chromosome 7, 16 (21%) with monosomy 7, 41 (55%) with losses of 7p (del(7p)), 16 (21%) with losses of 7q (del(7q)), and two (3%) with losses involving both arms. Patients with losses involving chromosome 7 were more likely to be X10 years old, National Cancer Institute (NCI) poor risk, and hypodiploid than patients lacking this abnormality. Patients with or without these abnormalities had similar early response to induction therapy. Event-free survival (EFS) and survival for patients with monosomy 7 (Po0.0001 and P ¼ 0.0007, respectively) or del(7p) (Po0.0001 and P ¼ 0.0001, respectively), but not of patients with del(7q), were significantly worse than those of patients lacking these abnormalities. The poorer EFS was maintained after adjustment for a Philadelphia (Ph) chromosome, NCI risk status, ploidy, or an abnormal 9p. However, the impact on survival was not maintained for monosomy 7 after adjustment for a Ph. These results indicate that the critical region of loss of chromosome 7 in pediatric ALL may be on the p-arm.

Genome complexity in acute lymphoblastic leukemia is revealed by array-based comparative genomic hybridization

“…This applies in particular to deletions of 7p, 13q and 16q, and gains of 17q, most of which have been described in other types of hematological malignancy (Fioretos et al, 1999;Scheurlen et al, 1999), including ALL (Chung et al, 2000;Heerema et al, 2000;Heerema et al, 2004). Although deletions of 16q are recurrent events in several hematological malignancies, including AML and multiple myeloma, they have not been previously identified in ALL.…”

Precursor B-acute lymphoblastic leukemia occurring in patients with a history of prior malignancies: is it therapy-related?

“…Loss of chromosome 7 is known to be an adverse prognostic indicator in pediatric precursor B-ALL, and is frequently observed in cases with hypodiploidy. 18 Analysis of deleted regions indicated that loss of 7p rather than 7q was critical prognostically; 18 and precursor B-ALL with -7 and -7p was distinct from myeloid disorders with -7 and -7q. Loss of chromosome of 17 in precursor B-ALL has been rarely reported.…”

A novel cytogenetic abnormality r(7)(::p11.2->q36.3::) in a Philadelphia-positive chronic myeloid leukemia case

“…It has been hypothesized that there is a tumor suppressor gene (TSG) on chromosome arm 7q that contributes to the pathogenesis of these diseases [18]. However, monosomy 7 or structural abnormalities resulting in the deletion of 7p were infrequent in childhood ALL to confer increased risk of treatment failure in Ph-positive cases, and it has been hypothesized that a TSG on 7p may contribute to the poor outcome of these patients [6].…”

“…Also it has been reported in adult ALL, in which they frequently occur as secondary aberrations associated with a Ph chromosome and it is an adverse factor in both childhood and adult Ph + ALL [6]. Additionally, deletions of 7p confer an inferior outcome in children with ALL, regardless of the presence of other poor prognostic features, whereas deletions of 7q are not associated with a worse outcome [6].…”