Diagnostic and prognostic significance of chromosome abnormalities in childhood acute lymphoblastic leukemia

Children with hyperdiploid but not triple trisomy (+4,+10,+17) acute lymphoblastic leukemia have an increased incidence of extramedullary relapse on current therapies: a single institution experience

To evaluate the outcome of children with high hyperdiploid acute lymphoblastic leukemia (hHDALL) treated at the author's institution. One hundred thirty-five consecutive children with B-precursor ALL were diagnosed between 1991 and 2002: 38 (28.1%) hHDALL and 97 (71.9%) non-hHDALL. In the hHDALL group, 11/38 (28.9%) relapsed at a median interval of 2.8 years (range: 0.8-5.0 years) with 9/11 relapses occurring at the end or after the completion of therapy. Three (27.3%) relapses were isolated hematopoietic (BM), while eight (72.7%) were either isolated extramedullary (EM) relapses (n=6; Testis: 4; CNS: 2) or combined hematopoietic and extramedullary relapses (n=2; BM + CNS: 1; BM + Testis: 1). For the non-hHDALL group, 29/97 (29.9%) relapsed. Unlike the hHDALL group, the non-hHDALL group experienced hematopoietic relapses (62%; n=18) more frequently than isolated extramedullary (27.5%; n=8: Testis: 1; CNS: 7) or combined hematopoietic and extramedullary relapses (10.3%; CNS + BM: 3), with 24/29 (82.8%) of the relapses occurring on therapy. Relapses in hHDALL frequently involved EM sites (P=0.053). Presence of triple trisomy of +4,+10,+17 at diagnosis had a protective effect against relapse (P<0.05). Five-year EFS for the hHDALL and non-hHDALL patients was similar, 70.5+/-7.5% and 66.4+/-4.9%, respectively. Five-year OS for the hHDALL patients was significantly higher than for the non-hHDALL patients, 92+/-4.5% vs. 74.1+/-4.5%, P=0.038. Biologically significant differences exist between relapse patterns of hHDALL and non-hHDALL cases related to relapse sites and time periods when relapses occur. hHDALL relapses continue to be chemo-sensitive.

A computer-aided method to expedite the evaluation of prognosis for childhood acute lymphoblastic leukemia

This study presented a fully-automated computer-aided method (scheme) to detect metaphase chromosomes depicted on microscopic digital images, count the total number of chromosomes in each metaphase cell, compute the DNA index, and correlate the results to the prognosis of childhood acute lymphoblastic leukemia (ALL). The computer scheme first uses image filtering, threshold, and labeling algorithms to segment and count the number of the suspicious "chromosome," and then computes a feature vector for each "detected chromosome." Based on these features, a knowledge-based classifier is used to eliminate those "non-chromosome" objects (i.e., inter-phase cells, stain debris, and other kinds of background noises). Due to the possible overlap of the chromosomes, a classification criterion was used to identify the overlapped chromosomes and adjust the initially counted number of the total chromosomes in each image. In this preliminary study with 60 testing images (depicting metaphase chromosome cells) acquired from three pediatric patients, the computer scheme generated results matched with the diagnostic results provided by the clinical cytogeneticists. The results demonstrated the feasibility or potential of using a computerized method to replace the tedious and the reader-dependent diagnostic methods commonly used in genetic laboratories to date.

Potential benefits of physical activity for children with acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia (ALL) is the most common form of paediatric leukaemia. The survival rate in children with ALL has improved significantly over the past several years, which makes quality of life an important focus for researchers. Some of the side effects of treatment (i.e. osteoporosis and obesity) are not realized until years after conclusion of therapy. Few studies have addressed the impact of physical activity (PA) on the side effects that occur during treatment of children with ALL. This paper discusses the increased risk for both osteoporosis and obesity due to treatment for ALL and suggests ways that PA may attenuate bone loss and risk of obesity by discussing what is known about effects of PA in healthy children and children with other chronic diseases. Recommendations will be made for PA interventions and future research in children with ALL.

High concordance from independent studies by the Children's Cancer Group (CCG) and Pediatric Oncology Group (POG) associating favorable prognosis with combined trisomies 4, 10, and 17 in children with NCI Standard-Risk B-precursor Acute Lymphoblastic Leukemia: a Children's Oncology Group (COG) initiative

Chromosome aberrations have a major role in pediatric acute lymphoblastic leukemia (ALL) risk assignment. The Children's Cancer Group (CCG) and the Pediatric Oncology Group (POG) independently assessed the significance of trisomy for chromosomes 4, 10, and 17 in National Cancer Institute (NCI) Standard- and High-Risk ALL. Data from 1582 (CCG) and 3902 (POG) patients were analyzed. Eight-year event-free survivals (EFS) of 91% (CCG) and 89% (POG) (P < 0.001) were achieved in patients assigned to NCI Standard Risk whose leukemic cells had simultaneous trisomies 4, 10, and 17. Both groups showed the degree of favorable prognostic importance increased with the actual number of favorable trisomies. POG analyses also demonstrated hyperdiploidy (> or =53 chromosomes) was less of an independently significant prognostic factor in the absence of these key trisomies. This finding supported conclusions from previous CCG and POG studies that specific trisomies are more important than chromosome number in predicting outcome in pediatric B-precursor ALL. In NCI Higher Risk patients, the number of favorable trisomies was not prognostically significant, but showed the same trend. Moreover, specific trisomies 4, 10, and 17 remain associated with favorable prognosis in Standard-Risk B-precursor ALL, even in the context of very different treatment approaches between the groups.

The influence of cyclin D1 (CCND1) 870A>G polymorphism and CCND1-thymidylate synthase (TS) gene-gene interaction on the outcome of childhood acute lymphoblastic leukaemia

The 870A>G polymorphism in the cyclin D1 (CCND1) gene modulates mRNA splicing, leading to altered protein that may affect the regulation of the G1/S cell-cycle checkpoint. This polymorphism has been reported to influence susceptibility to and progression of several malignancies. Furthermore, the change of retinoblastoma protein regulation mediated by CCND1 may play a role in the development of methotrexate (MTX) resistance via an associated higher activity of enzymes that are inhibited by MTX. This study shows that children with acute lymphoblastic leukaemia (ALL) who are homozygous for the CCND1 A variant have a lower probability of event-free survival (P = 0.006) compared to carriers of the G variant. A significant result is retained in the presence of other prognostic factors. This impact is even more apparent in individuals who are also homozygous for thymidylate synthase (TS) triple repeat (P < 0.00005), which has previously been shown to influence the outcome of childhood ALL.

Long-term study of the clinical significance of loss of heterozygosity in childhood acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is one of the most common malignancies in childhood, with a widely variable outcome. Differences in the behavior and prognosis of the leukemia suggest that ALL can be divided into several biologic subgroups. We analyzed the loss of heterozygosity (LOH) of 6q, 9p, 11q and 12p using 31 microsatellite sites to determine their overall frequency and clinical value. We have studied 244 primary ALL samples obtained from the Multicenter Trial ALL-BFM 90 of Childhood ALL group. These patients have now been followed clinically for over 8 years. LOH occurred in 169 (69%) individuals in the following frequencies: 6q, 49 patients (20%); 9p, 97 patients (40%); 11q, 29 patients (12%); 12p, 60 patients (25%). Clinical data showed that those with 6q LOH were younger (P = 0.01) and had lower WBC counts (P = 0.02); patients with 9p LOH more frequently had CNS involvement (P = 0.01) and T cell phenotype (P = 0.0001); individuals with 11q LOH had a good response to induction chemotherapy (P = 0.02); those with 12p LOH were younger (P = 0.005), frequently had precursor B ALL (P = 0.001), and had a longer event-free survival (P = 0.05). Taken together, these data confirm that LOH is a very frequent alteration in childhood ALL.

Bone marrow stroma-supported culture of T-lineage acute lymphoblastic leukemic cells predicts treatment outcome in children: a Pediatric Oncology Group study

Significant predictors of treatment outcome are poorly defined for patients with T-lineage acute lymphoblastic leukemia (T-ALL). A high WBC at diagnosis, which has traditionally been a predictor of poor response in T-ALL, has considerably weakened prognostic significance in the face of modern, more intensive chemotherapy. To test the hypothesis that bone marrow stroma-supported leukemic cell recovery might identify children at high risk for relapse, we measured the ex vivo recovery of T-ALL lymphoblasts from 29 newly diagnosed patients using a stromal cell co-culture assay. In all cases the T-ALL lymphoblasts showed an increase in recovery of T-ALL cells (RTC), ranging from 4 to 343%, in comparison to samples maintained without stroma. Since we were blinded to patient outcome in this case-control study, we then correlated patient outcome with RTC. The RTC for 18 patients in complete continuous remission (CCR) for greater than 4 years was stochastically larger than for the 11 patients who eventually relapsed (P = 0.011, by the two-sided Wilcoxon test). Furthermore, 100% of patients with an RTC of more than 26% had a CCR greater than 4 years while 78% of the patients with an RTC of less than 25% relapsed within 4 years. This is the first report to show that higher lymphoblast recovery may predict a more favorable outcome for children with T-ALL. A prospective study is needed to test whether stroma-supported leukemic cell recovery might serve as a basis for assigning risk-adjusted therapy.