Nonrandom abnormalities of chromosome 9p in childhood acute lymphoblastic leukemia: association with high-risk clinical features

To assess the frequency and significance of nonrandom abnormalities of chromosome 9p in childhood acute lymphoblastic leukemia (ALL), we analyzed our experience with 398 consecutive cases with completely banded karyotypes. Forty cases (10%) with abnormalities of 9p were identified: 26 with deletions, nine with unbalanced translocations resulting in the loss of 9p material, and five with apparently balanced reciprocal translocations. As compared with children with ALL lacking 9p abnormalities, these 40 cases were significantly older, had higher initial circulating WBC counts, more "lymphomatous" disease characteristics (including presence of a mediastinal mass in 15%. T- cell phenotype in 26%, splenomegaly greater than 8 cm in 25%), an increased failure rate in the first 2 to 3 years after diagnosis, and a higher incidence of extramedullary relapse. Conversely, lymphomatous ALL cases were twice as likely (19% v 8%) to have an abnormality of chromosome 9p than ALL cases lacking lymphomatous features (P = .01). The finding of an abnormal chromosome 9p, however, was not specific for lymphomatous ALL or T-cell lineage, because most cases were neither lymphomatous nor T-cell, and the overall Kaplan-Meier distribution of treatment failures for abnormal 9p cases was not statistically significantly different from control ALL cases receiving the same treatment who lacked abnormalities of 9p (P = .06, by log-rank test). We conclude that nonrandom abnormalities of chromosome 9p, especially a breakpoint in 9p21-22, occur with increased frequency in childhood ALL in association with some high-risk clinical features. Despite this association, the chromosome anomaly is nonspecific in its syndrome delineation and confers no major adverse consequence on long-term survival of childhood ALL treated with modern therapy. However, due to an apparently increased hazard of involvement of the CNS (eight of 17 failures), it may be inadvisable to lessen the intensity of CNS preventive therapy for this group of patients.     

Preferential infiltration of liver sinusoids in acute lymphoblastic leukemia

We report a case of acute lymphoblastic leukemia (ALL) presenting as severe jaundice. The patient, a 59-year-old man, was found to have abnormal liver function, including an elevated total bilirubin level (13.5 mg/dl) with hepatosplenomegaly, but no detectable lymphadenopathy. A liver biopsy and bone marrow examination revealed a lymphoid neoplasm. Pathologic features included invasion of an abnormal clone into the sinusoidal region of the liver, diffuse bone marrow involvement (41.6% of all nucleated cells) and splenomegaly. Small numbers of malignant cells were also detected in the peripheral blood. B-cell markers, such as terminal deoxynucleotidyl transferase (TdT), CD10, CD19, CD20 and HLA-DR were positive, and CD2, CD3, CD4, CD5, CD7, CD8, kappa, lambda, cytoplasmic mu and myeloperoxidase were negative. Cytogenetic analysis detected hyperdiploidy. In this case, a dose-attenuated CHOP regimen attained complete remission. To date, preferential infiltration to liver sinusoids has been noted in hepatosplenic gamma/delta T-cell lymphoma, other NK/T-cell malignancies, and some cases of hairy cell leukemia. Severe jaundice due to preferential infiltration of leukemic cells into liver sinusoids is rather uncommon as a presenting feature of ALL.     

Langerhans cell histiocytosis following childhood acute lymphoblastic leukemia.

Langerhans cell histiocytosis (LCH) is a clonal proliferation of Langerhans cells of unknown etiology that results in a range of clinical manifestations. LCH has been known to be associated with a variety of malignant diseases. A 7-year-old boy was treated for standard-risk acute lymphoblastic leukemia (ALL) at age 2 years, on a Children's Cancer Group chemotherapy protocol for 3 years and developed LCH 2 years after completion of chemotherapy. The case and a review of literature on the association of LCH and ALL are presented.     

Unravelling an HLA-DR association in childhood acute lymphoblastic leukemia.

Genetic and environmental factors play an interactive role in the development of childhood acute lymphoblastic leukemia (ALL). Since the demonstration of a major histocompatibility complex (MHC) influence on mouse leukemia in 1964, an HLA association has been considered as a possible genetic risk factor. Despite extensive efforts, however, no strong evidence comparable to the H-2(k) influence on mouse leukemia has been shown. The number of negative serological studies resulted in a loss of interest and consequently, no molecular HLA-DR association study has been published to date. We reconsidered the HLA-DR association in childhood ALL in 114 patients from a single center and 325 local newborn controls by polymerase chain reaction (PCR) analysis of the HLA-DRB1/3/4/5 loci. With conventional analysis, there was a moderate allelic association with the most common allele in the HLA-DR53 group, HLA-DRB1*04, in the whole group that was stronger in males (P =.0005, odds ratio = 2.9). When the other expressed HLA-DRB loci were examined, homozygosity for HLA-DRB4*01, encoding the HLA-DR53 specificity, was increased in patients (21.1% v 8.3%; odds ratio = 2.9, P =.0005). Consideration of gender showed that all of these associations were reflections of a male-specific increase in homozygosity for HLA-DRB4*01 (32.8% v 4. 0%; odds ratio = 11.7, 95% confidence interval [CI] = 4.9 to 28.0; P = 3 x 10(-8)). This highly significant result provided the long-suspected evidence for the HLA-DR influence on the development of childhood ALL while confirming the recessive nature of the MHC influence on human leukemogenesis as in experimental models. The cross-reactivity between HLA-DR53 and H-2Ek, extensive mimicry of the immunodominant epitope of HLA-DR53 by several carcinogenic viruses, and the extra amount of DNA in the vicinity of the HLA-DRB4 gene argue for the case that HLA-DRB4*01 may be one of the genetic risk factors for childhood ALL.     

FLT3 mutations in childhood acute lymphoblastic leukemia

Activating mutations of the FLT3 receptor tyrosine kinase are common in acute myelogenous leukemia (AML) but are rare in adult acute lymphoblastic leukemia (ALL). We have recently shown that FLT3 is highly expressed and often mutated in ALLs with rearrangement of the mixed lineage leukemia (MLL) gene on chromosome 11q23. Because hyperdiploid ALL samples also show high-level expression of FLT3, we searched for the presence of FLT3 mutations in leukemic blasts from 71 patients with ALL. The data show that approximately 25% (6 of 25) of hyperdiploid ALL samples possess FLT3 mutations, whereas only 1 of 29 TEL/AML1-rearranged samples harbored mutations (P =.04, Fisher exact test). Three mutations are novel in-frame deletions within a 7-amino acid region of the receptor juxtamembrane domain. Finally, 3 samples from patients whose disease would relapse harbored FLT3 mutations. These data suggest that patients with hyperdiploid or relapsed ALL might be considered candidates for therapy with newly described small-molecule FLT3 inhibitors.     

Haploidentical transplantation for acute lymphoblastic leukemia in childhood

Haploidentical transplantation in childhood acute lymphoblastic leukemia (ALL) is a promising option for children lacking a suitable donor. We have updated our series of patients with ALL and report the results. Additionally, we reviewed the literature and try to embed our own experiences in the published results. We performed HLA-mismatched stem cell transplantations with megadoses of purified positively selected mobilized peripheral blood CD34+ progenitor cells (PBPC) from adult donors in 27 children with acute lymphoblastic leukemia (ALL) in first (CR1 n = 7), second (CR2 n = 10), or third (CR3 n = 4) complete remission, and in refractory state (NR n = 6). The patients received a mean number of 19.1+/-11.3 x 10(6)/kg purified CD34+ and a mean number of 15.5+/-24.2 x 10(3)/kg CD3+ T-cells. No additional graft-versus-host disease (GVHD) prophylaxis was used, except as short-term CSA in the first 3 patients. The myeloablative treatment was based on busulfan in 12 and on TBI in 14 patients. One patient was grafted with a non-myeloablative approach. Engraftment was rapid in 26 patients, with two patients suffering from a rejection. These two and one patient with initial non-engraftment had been successfully regrafted. The probability of survival of the total group is 0.34+/-0.09; the 12 patients transplanted in remission showed a probability of survival of 0.44+/-0.11. None of the patients transplanted in non-remission survived. There was no statistical difference in survival for patients with a 1, 2 or 3 antigen mismatched donor (out of 6 HLA antigens) or for patients in 1st, 2nd or 3rd remission. Causes of death were relapses in 10 patients, veno-occlusive disease (VOD) in 1, multi-organ failure (MOF) in 2 and infections in 4 patients. 3/24 evaluable patients without any additional GVHD-prophylaxis developed grade 1 or 2 GVHD. Ten patients were treated with additional donor lymphocyte infusion (DLI), from which 4 developed a maximum grade 3 GVHD. We conclude that the HLA barrier can be overcome by transplantation of megadoses of highly purified CD34+ PBPC and GVHD can effectively be prevented. This approach offers a promising treatment option for patients with acute lymphoblastic leukemia needing urgently transplantation but lacking a suitable donor.     

Philadelphia chromosome positive childhood acute lymphoblastic leukemia

In a 3-yr period, the Philadelphia chromosome (Ph1) was found in 4 of 43 children with acute lymphoblastic leukemia (ALL) in whom chromosomes were studied at diagnosis. The clinical, morphological, cytochemical, and immunologic findings in the Ph1-positive (PH1+) CASES WERE CONsistent with typical childhood ALL, indicating that identification of cases requires chromosome studies. A review of all reported cases of Ph1 + childhood ALL shows that Ph1 + patients are older and have higher initial platelet and white blood cell counts (WBC) than most children with ALL. However, a life table comparison between the reported cases of Ph1 + ALL in children and randomly selected age-, sex-, and WBC- matched controls with ALL shows the duration of first marrow remission to be significantly shorter (p less than 0.02) for the Ph1 + cases Ph1 + ALL is a distinct subtype of childhood ALL that is not rare and can be identified only by cytogenetic studies. The prognosis is poor. Cytogenetic studies should be done prospectively in a large group of children with ALL to define further the subgroup of patients and to confirm the findings of this retrospective analysis.     

Outcome after relapse in childhood acute lymphoblastic leukemia

Among 157 children with acute lymphoblastic leukemia (ALL) who experienced relapse at 54 institutes participating in the Japan Association of Childhood Leukemia Study, we analyzed the outcomes after relapse in 103 and 30 eligible cases with bone marrow (BM) and central nervous system (CNS) relapse, respectively. Reinduction rates in BM and CNS relapse cases were 72.3% and 83.3%, respectively. High reinduction rates were observed in B-precursor (B-pre) phenotype ALL in both relapse groups and in late (more than 24 months from onset) BM-relapse patients. After BM relapse, the overall 5-year survival rate was superior in the allogeneic stem cell transplantation (SCT) group compared to the non-SCT group (41.9%+/-8.2% versus 13.6%+/-6.5%, P < .0001). In contrast, the 4-year overall survival rate was not significantly different between the SCT (allogeneic plus autologous) and non-SCT groups after CNS relapse (26.8%+/-14.2% versus 61.9%+/-12.3%, P = .252). The late BM-relapse patients showed a significantly higher survival rate than did early-relapse patients, and survival rates were similar between the allogeneic and autologous group when the patients underwent SCT during a second complete remission. Moreover, B-pre ALL patients classified in the standard-risk group according to National Cancer Institute/Rome's criteria at onset had a good prognosis after allogeneic SCT. Improving the cure rate in relapsed ALL patients requires more intensive reinduction therapy and efforts to succeed with SCT in early BM-relapse patients as well as the establishment of a treatment strategy including indications of SCT for CNS-relapse patients.     

Outcome heterogeneity in childhood high-hyperdiploid acute lymphoblastic leukemia

High hyperdiploidy (HeH) (51 to 65 chromosomes) is found in one third of children with acute lymphoblastic leukemia and is associated with a good prognosis. Cytogenetic features may further refine this prognosis and identify patients with a poor outcome. We examined the effect of sex, age, individual trisomies, modal number, and structural abnormalities on survival among 700 children with HeH. Univariate analysis showed that age. sex, +4, +10, +18, and a high modal number were associated with survival. Multivariate analysis however, revealed that only age, sex, +4, and +18 were independent indicators. Hazard scores for predicting relapse and mortality were constructed. Three risk groups with 5-year event-free survival (EFS) rates of 86%, 75%, and 50% (P <.0001) were identified. The high-risk group comprised boys older than 9 years, boys aged 1 through 9 years without +18, and girls older than 9 years without +18, while girls aged 1 through 9 years with +18 had the best EFS. In terms of mortality, those younger than age 10 years with both +4 and +18 had an improved survival (96% vs 84% at 5 years, P <.0001). These findings confirm that the outcome of children with HeH is heterogeneous and that specific trisomies can identify patients with the greatest and least risk of treatment failure.     

Formation of a hyperdiploid karyotype in childhood acute lymphoblastic leukemia.

Hyperdiploidy with greater than or equal to 50 chromosomes is a frequent and distinct karyotypic pattern in the malignant cells of children with acute lymphoblastic leukemia. To understand better the mechanism of formation of the hyperdiploid karyotype, we studied 15 patients using 20 DNA probes that detect restriction fragment length polymorphisms. We first examined disomic chromosomes for loss of heterozygosity. Two patients had widespread loss of heterozygosity on all informative disomic chromosomes, and represent cases of near-haploid leukemia in which the chromosomes doubled. One other patient had loss of heterozygosity limited to chromosome 3; in this patient all of seven other informative disomic chromosomes retained heterozygosity. Loss of heterozygosity was not detected in the remaining 12 patients on a total of 87 informative disomic chromosomes. We then examined tetrasomic chromosomes for parental dosage. Of the 13 patients in whom widespread loss of heterozygosity was not present, 11 patients had tetrasomy 21; 10 of 11 (91%) had an equal dose of maternal and paternal alleles on chromosome 21 and only 1 of 11 (9%) had an unequal dose of parental alleles in a 3:1 ratio. These results suggest that the hyperdiploid karyotype usually arises by simultaneous gain of chromosomes from a diploid karyotype during a single abnormal cell division, and occasionally by doubling of chromosomes from a near-haploid karyotype. The hyperdiploidy in cases without widespread loss of heterozygosity is not caused by stepwise or sequential gains from a diploid karyotype or by losses from a tetraploid karyotype; the former should result in a 3:1 parental dosage for 67% of tetrasomic chromosomes (9% observed) and the latter should result in loss of heterozygosity for 33% of disomic chromosomes (1% observed). Additional studies of the molecular basis for this leukemia subtype are warranted.