The role of prognostic features in the treatment of childhood acute lymphoblastic leukemia

Hyperleukocytosis in Childhood Acute Leukemia: Early Complications and Survival Outcomes

Hyperleukocytosis and extreme hyperleukocytosis, defined as initial white blood cell counts greater than 100 × 10⁹/L and 200 × 10⁹/L, respectively, have been associated with unfavorable outcomes. This study aimed to determine the early complications and survival outcomes of childhood leukemia patients with hyperleukocytosis. The medical records of 690 children newly diagnosed with acute leukemia between January 1998 and December 2017 were retrospectively reviewed. The Kaplan-Meier method and log-rank test were used to assess and compare the survival outcomes. Multivariate Cox proportional hazards regression was used to determine associated risk factors for overall survival. We found that 16.6% of 483 childhood acute lymphoblastic leukemia (ALL) patients and 20.3% of 207 childhood acute myeloid leukemia (AML) patients had hyperleukocytosis at diagnosis. ALL patients with hyperleukocytosis had more early complications than those without hyperleukocytosis (p < 0.05). Among the ALL group, the 5-year overall survival rate for those with hyperleukocytosis was significantly lower than for those without hyperleukocytosis (37.2% vs. 67.8%, p < 0.0001), while the difference was not statistically significant in the AML group (19.0% vs. 30.2%, respectively, p = 0.26). Hyperleukocytosis (hazard ratio [HR]: 2.04), extreme hyperleukocytosis (HR: 2.71), age less than 1 year (HR: 3.05), age greater than 10 years (HR: 1.64), and male sex (HR: 1.37) were independently associated with poorer overall survival in childhood ALL patients. Extreme hyperleukocytosis (HR: 2.63) and age less than 1 year (HR: 1.82) were independently associated with poorer overall survival in AML patients. Hyperleukocytosis was associated with adverse survival outcomes in childhood leukemia.

Gene Mutations Related to Glucocorticoid Resistance in Pediatric Acute Lymphoblastic Leukemia

OBJECTIVE

To investigate the correlation between gene mutations and glucocorticoid resistance in pediatric acute lymphoblastic leukemia (ALL).

METHODS

A total of 71 children with ALL admitted to our center between September 2019 and September 2021 were enrolled. DNA obtained from bone marrow or peripheral blood samples at initial diagnosis was used for genetic testing via whole exome sequencing. Meanwhile, patient clinical information was collected. Subsequently, the correlations of gene mutations with clinical features and glucocorticoid resistance were analyzed.

RESULTS

Of the 71 children enrolled, 61 (85.9%) had B-cell ALL (B-ALL) and 10 (14.1%) had T-cell ALL (T-ALL). The five genes with the highest mutation frequency in B-ALL were TTN (24.4%), FLT3 (14.6%), TP53 (14.6%), MUC16 (9.8%), and EPPK1 (9.8%). In contrast, those with the highest frequency in T-ALL were NOTCH1 (54.5%), FBXW7 (27.3%), TTN (27.3%), MUC16 (27.3%), and PHF6 (18.2%). Upon statistical analysis, TTN and NOTCH1 mutations were found to be associated with prednisone resistance. Further, TTN and MUC16 mutations were associated with a lower age at diagnosis, and NOTCH1 mutations were associated with T-ALL in female patients. Leukocyte counts and LDH levels did not differ based on the presence of any common gene mutation, and no association between these gene mutations and overall survival was observed.

CONCLUSIONS

Our study is the first to demonstrate the association between TTN mutation and glucocorticoid resistance in ALL. Our findings could guide strategies for overcoming drug resistance and aid in the development of drug targets.

Réponse à un schéma chimiothérapeutique administré à des enfants atteints de LAL à cellules pré-B à risque élevé selon le protocole COG

Objectif

La présente étude a pour but d'examiner la réponse à un schéma chimiothérapeutique administré à des enfants atteints de LAL à cellules pré-B à risque élevé selon le protocole COG.

Méthode

L'étude transversale porte sur 55 enfants traités selon le protocole du groupe d'oncologie pédiatrique (mieux connu sous le nom de Children's Oncology Group ou COG), de septembre 2010 à février 2015, et évalue les résultats du schéma chimiothérapeutique.

Résultats

Durant la première semaine suivant le traitement, le taux de rétablissement complet a été de 76,4 %. Les taux de survie après trois ans et cinq ans étaient respectivement de 85,5 % et de 81 %. Le taux de rechute après le premier épisode de rémission a été de 20 % et le taux de mortalité consécutif à cette rechute a été de 50 %. Trente pour cent de l'ensemble des décès ont eu lieu durant la période d'induction. Dans tous les cas, une septicémie en est la cause.

Conclusion

Les résultats indiquent que le taux de survie a augmenté. Il est donc possible d'améliorer le taux de survie en optant pour le protocole COG et en contrôlant les infections chez les patients, et ce, sans égard au groupe de risque.

The outcome of chemotherapeutic regimen by high-risk pre-B-cell protocol in ALL children

Objective

The aim of this study was to investigate the outcome of chemotherapeutic regimen by high-risk pre-B-cell potocol in ALL children.

Methods

The cross-sectional study was conducted on 55 children who were treated with the Children Oncology Group (COG) protocol from September 2010 to February 2015 to evaluate the chemotherapeutic regimen results.

Results

There was a complete recovery rate of 76.4% during the first week after treatment. Three-year overall survival was 85.5% and five-year overall survival was 81%. Relapse rate after first remission was 20% and death after relapse was 50%. Thirty percent of total deaths were at the induction period. All of the deceased cases died due to sepsis.

Conclusion

Results showed that the survival rate increased. By choosing the COG protocol and by controlling infection in patients without considering the risk group we can improve survival rates.

Functional characterization of NK cells in Mexican pediatric patients with acute lymphoblastic leukemia: Report from the Mexican Interinstitutional Group for the Identification of the Causes of Childhood Leukemia

Acute lymphoblastic leukemia (ALL) is the most common cancer in children around the globe. Mexico City has one of the highest incidence rates of childhood leukemia worldwide with 49.5 cases per million children under the age of 15 which is similar to that reported for Hispanic populations living in the United States. In addition, it has been noted a dismal prognosis in Mexican and Hispanic ALL pediatric population. Although ALL, like cancer in general, has its origins in endogenous, exogenous, and genetic factors, several studies have shown that the immune system also plays a deterministic role in cancer development. Among various elements of the immune system, T lymphocytes and NK cells seem to dominate the immune response against leukemia. The aim of the present study was to perform a phenotypic and functional characterization of NK cells in ALL Mexican children at the moment of diagnosis and before treatment initiation. A case-control study was conducted by the Mexican Interinstitutional Group for the Identification of the Causes of Childhood Leukemia (MIGICCL). 41 cases were incident ALL children younger than 17 years old and residents of Mexico City. 14 controls were children without leukemia, matched by age and sex with cases. NK cell function was evaluated by degranulation assays towards K562 cells and SLAM-associated protein (SAP) expression was measured by intracellular staining. All assays were performed using peripheral blood mononuclear cells from controls and patients. The results indicate that NK mediated cytotoxicity, measured by CD107a degranulation assays in response to K562 cells, was reduced in ALL patients compared to controls. Interestingly, an impaired NK cell killing of target cells was not equally distributed among ALL patients. In contrast to patients classified as high-risk, standard-risk patients did not display a significant reduction in NK cell-mediated cytotoxicity. Moreover, patients presenting a leukocyte count ≥ 50,000xmm³ displayed a reduction in NK-cell mediated cytotoxicity and a reduction in SAP expression, indicating a positive correlation between a reduced SAP expression and an impaired NK cell-mediated citotoxicity. In the present study it was observed that unlike patients with standard-risk, NK cells from children presenting high-risk ALL, harbor an impaired cytotoxicity towards K562 at diagnosis. In addition, NK cell function was observed to be compromised in patients with a leukocyte count ≥50,000xmm³, where also it was noticed a decreased expression of SAP compared to patients with a leukocyte count <50,000xmm³. These data indicate NK cell-mediated cytotoxicity is not equally affected in ALL patients, nevertheless a positive correlation between low SAP expression and decreased NK cell-mediated cytotoxicity was observed in ALL patients with a leukocyte count ≥50,000xmm³. Finally, an abnormal NK cell-mediated cytotoxicity may represent a prognostic factor for high-risk acute lymphoblastic leukemia.

Comparison of Diagnostic Yield of a FISH Panel Against Conventional Cytogenetic Studies for Hematological Malignancies: A South Indian Referral Laboratory Analysis Of 201 Cases

Objectives:

Genetic markers are crucial fort diagnostic and prognostic investigation of hematological malignancies (HM). The conventional cytogenetic study (CCS) has been the gold standard for more than five decades. However, FISH (Fluorescence in Situ Hybridization) testing has become a popular modality owing to its targeted approach and the ability to detect abnormalities in non-mitotic cells. We here aimed to compare the diagnostic yields of a FISH panel against CCS in HMs.

Methods:

Samples of bone marrow and peripheral blood for a total of 201 HMs were tested for specific gene rearrangements using multi-target FISH and the results were compared with those from CCS.

Results:

Exhibited a greater diagnostic yield with a positive result in 39.8% of the cases, as compared to 17.9% of cases detected by CCS. Cases of chronic lymphocytic leukaemia (CLL) benefited the most by FISH testing, which identified chromosomal aberrations beyond the capacity of CCS. FISH was least beneficial in myelodysplastic syndrome (MDS) where the highest concordance with CCS was exhibited. Acute lymphocytic leukaemia (ALL) demonstrated greater benefit with CCS. In addition, we found the following abnormalities to be most prevalent in HMs by FISH panel testing: RUNX1 (21q22) amplification in ALL, deletion of D13S319/LAMP1 (13q14) in CLL, CKS1B (1q21) amplification in multiple myeloma and deletion of EGR1/RPS14 (5q31/5q32) in MDS, consistent with the literature.

Conclusions:

In conclusion, FISH was found to be advantageous in only a subset of HMs and cannot completely replace CCS. Utilization of the two modalities in conjunction or independently should depend on the indicated HM for an optimal approach to detecting chromosomal aberrations.

Effect of Malnutrition at Diagnosis on Clinical Outcomes of Children With Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is the most common malignancy among children. Although studies have shown that malnutrition can negatively affect treatment outcome, results are controversial. This retrospective study aims at determining the prevalence of malnutrition and its association with treatment outcome among children with ALL treated at the Children's Cancer Institute in Lebanon. A total of 103 patients diagnosed with ALL between April 2002 and May 2010 were enrolled. Anthropometric data were collected from medical records upon diagnosis, at 3 and 6 months, and at the end of treatment. Body mass index was calculated for children 2 years of age and older, whereas weight-for-height ratio was used for patients below 2 years. Patients were considered underweight, stunted, or wasted if their Z-scores were <-2 SD. The prevalence of malnourished children was 25.2% at diagnosis and remained almost the same at the end of treatment. The odds of having a poor outcome (death and relapse) was higher among malnourished children and more so among stunted children with an odds ratios=2.15; 95% confidence interval, 0.5-8.3 and odds ratio=2.63; 95% confidence interval, 0.6-11.5, respectively. Although there was a trend showing worse outcomes in malnourished children with ALL at diagnosis when compared with well-nourished children larger studies using additional tools like arm anthropometry need to be conducted to prove the association.

Intracellular Signaling Pathways Involved in Childhood Acute Lymphoblastic Leukemia; Molecular Targets

Acute lymphoblastic leukemia (ALL) is a malignant disease characterized by an uncontrolled proliferation of immature lymphoid cells. ALL is the most common hematologic malignancy in early childhood, and it reaches peak incidence between the ages of 2 and 3 years. The prognosis of ALL is associated with aberrant gene expression, in addition to the presence of numerical or structural chromosomal alterations, age, race, and immunophenotype. The Relapse rate with regard to pharmacological treatment rises in childhood; thus, the expression of biomarkers associated with the activation of cell signaling pathways is crucial to establish the disease prognosis. Intracellular pathways involved in ALL are diverse, including Janus kinase/Signal transducers and transcription activators (JAK-STAT), Phosphoinositide-3-kinase-protein kinase B (PI3K-AKT), Ras mitogen-activated protein kinase (Ras-MAPK), Glycogen synthase kinase-3β (GSK-3β), Nuclear factor-kappa beta (NF-κB), and Hypoxia-inducible transcription factor 1α (HIF-1α), among others. In this review, we present several therapeutic targets, intracellular pathways, and molecular markers that are being studied extensively at present.

Acute lymphoblastic leukemia in children and adolescents: prognostic factors and analysis of survival

Objective

To describe the clinical and laboratory features of children and adolescents with acute lymphoblastic leukemia treated at three referral centers in Ceará and evaluate prognostic factors for survival, including age, gender, presenting white blood cell count, immunophenotype, DNA index and early response to treatment.

Methods

Seventy-six under 19-year-old patients with newly diagnosed acute lymphoblastic leukemia treated with the Grupo Brasileiro de Tratamento de Leucemia da Infância – acute lymphoblastic leukemia-93 and -99 protocols between September 2007 and December 2009 were analyzed. The diagnosis was based on cytological, immunophenotypic and cytogenetic criteria. Associations between variables, prognostic factors and response to treatment were analyzed using the chi-square test and Fisher's exact test. Overall and event-free survival were estimated by Kaplan–Meier analysis and compared using the log-rank test. A Cox proportional hazards model was used to identify independent prognostic factors.

Results

The average age at diagnosis was 6.3 ± 0.5 years and males were predominant (65%). The most frequently observed clinical features were hepatomegaly, splenomegaly and lymphadenopathy. Central nervous system involvement and mediastinal enlargement occurred in 6.6% and 11.8%, respectively. B-acute lymphoblastic leukemia was more common (89.5%) than T-acute lymphoblastic leukemia. A DNA index >1.16 was found in 19% of patients and was associated with favorable prognosis. On Day 8 of induction therapy, 95% of the patients had lymphoblast counts <1000/μL and white blood cell counts <5.0 × 10⁹/L. The remission induction rate was 95%, the induction mortality rate was 2.6% and overall survival was 72%.

Conclusion

The prognostic factors identified are compatible with the literature. The 5-year overall and event-free survival rates were lower than those reported for developed countries. As shown by the multivariate analysis, age and baseline white blood cell count were independent prognostic factors.

Prognostic cytogenetic markers in childhood acute lymphoblastic leukemia: Cases from Mansoura Egypt

The objective of the work was to evaluate children with acute lymphoblastic leukemia (ALL) showing resistance to immediate induction chemotherapy in relation to conventional and advanced cytogenetic analysis. The study was conducted on 63 ALL children (40 males and 23 females) with age range 4.5 months-16 years (mean = 7.76 years). They included 37 cases who attained a true remission and 26 complicated by failure of remission, early relapse or death. They were subjected to history, clinical examination and investigations including CBC, BM examination, karyotyping, FISH for translocations and flowcytometry for immunophenotyping and minimal residual disease diagnosis. Cases aged < 5 years; male sex with organomegaly had better remission although statistically insignificant. Initially low HB < 8 gm/dl, high WBCs and platelet counts >50.000/mm(3) also showed better but non-significant remission rates. Most of our cases were L(2) with better remission compared to other immunophenotypes. About 40 informative karyotypes were subdivided into 15 hypodiploid, 10 pseudodiploid, 8 normal diploid and 7 hyperdiploid cases; the best remission rates were noticed among the most frequent ploidy patterns. Chromosomes 9, 11 and 22 were the most frequently involved by structural aberrations followed by chromosomes 5, 12 and 17. Resistance was noted with aberrations not encountered among remission group; deletions involving chromosomes 2p, 3q, 10p and 12q; translocations involving chromosome 5; trisomies of chromosomes 16 and 21; monosomies of 5 and X and inversions of 5 and 11. Our conclusions were that cytogenetic and molecular characterizations of childhood ALL could add prognostic criteria for proper therapy allocation.

Prognostic cytogenetic markers in childhood acute lymphoblastic leukemia: Cases from Mansoura, Egypt

OBJECTIVE

To evaluate children with acute lymphoblastic leukemia (ALL) showing resistance to immediate induction chemotherapy in relation to conventional and advanced cytogenetic analysis.

SUBJECTS AND METHODS

This work was conducted on 63 ALL children (40 males and 23 females) with age range 4.5 months-16 years (mean = 7.76 years). They included 37 cases who attained true remission and 26 complicated by failure of remission, early relapse or death. They were subjected to history, clinical examination and investigations including CBC, BM examination, karyotyping, FISH for translocations and flow cytometry for immunophenotyping and minimal residual disease diagnosis.

RESULTS

Cases aged < 5 years; male sex with organomegaly had better remission although statistically insignificant. Initially low Hb < 8 gm/dl, high WBCs and platelet counts > 50,000/mm(3) also showed better but non-significant remission rates. Most of our cases were L(2) with better remission compared to other immunophenotypes. Forty informative karyotypes were subdivided into 15 hypodiploid, 10 pseudodiploid, 8 normal diploid and 7 hyperdiploid cases; the best remission rates were noticed among the most frequent ploidy patterns. Chromosomes 9, 11 and 22 were the most frequently involved by structural aberrations followed by chromosomes 5, 12 and 17. Resistance was noted with aberrations not encountered among remission group; deletions involving chromosomes 2p, 3q, 10p and 12q; translocations involving chromosome 5; trisomies of chromosomes 16 and 21; monosomies of 5 and X and inversions of 5 and 11.

CONCLUSIONS

Cytogenetic and molecular characterizations of childhood ALL may add prognostic criteria for optimal therapy allocation.

Markers of apoptosis and proliferation related gene products as predictors of treatment outcome in childhood acute lymphoblastic leukemia

The aim of the study is to characterize markers of apoptosis in children with acute lymphoblastic leukemia (ALL) in relation to treatment outcome of the disease. The study was performed on 34 children with ALL and 39 healthy children as a control group. Apoptosis was assessed by cell morphology; DNA fragmentation; ELISA and RT-PCR for CD95, CD95L, BcL-2 and nuclear factor-kappa B (NF-kappaB); and flow cytometry for CD95, CD40, CD49d and CD11a. Apoptosis was significantly lower in patients than controls. Apoptosis detected by CD95 ligand was significantly lower in cases with no remission after treatment than those who achieved remission. Anti-apoptotic factors: CD40, BcL-2, and NF-kappaB were all found to be higher in cases than controls and in cases with no remission than those achieved remission. CD49d was significantly lower in cases than controls, and significantly lower in cases with who did not achieve remission. CD11a levels were similar in the various groups. Delayed apoptosis of ALL cells is genetically controlled either directly or indirectly by a network of oncogenes and tumor suppressor genes. CD40 appeared to stimulate both T and B lineage and is considered the most potent influencer and predictor of resistance to therapy. Inhibitors for the activity of CD40, Bcl-2 and NF-kappaB as well as stimulants to CD95 could have a potential therapeutic benefit.

The outcome of allogeneic hematopoietic stem cell transplants without total body irradiation in pediatric patients with acute lymphoblastic leukemia: single centre experience

The most widely accepted conditioning regimen to allogeneic hematopoietic stem cell transplantation consists of total body irradiation, especially in patients affected by acute lymphoblastic leukemia (ALL). In this retrospective study, we report our experience on hematopoietic stem cell transplantation in 44 pediatric patients with acute lymphoblastic leukemia using a non-radiation-based conditioning regimen (busulfan/cyclophosphamide). Median age at transplantation was 12.5 years (range, 4 to 14 y). 39 out of 44 patients received transplants in complete remission. At a median follow-up of 390 days, the probabilities of 3-year disease-free survival and overall survival were 50% and 68%, respectively. Disease status of hematopoietic stem cell transplantation was the only significant variable affecting the overall survival. Acute and chronic graft-versus-host disease occurred in 23 (64%) and 12(18%) patients, respectively. Relapse was significantly higher among patients transplanted in advanced disease status. The results of the study indicate that non-radiation-based preparative regimens can be used in pediatric patients with ALL. However, well-designed comparative trials are needed to better clarify the difference between radiation and non-radiation-based conditioning regimens in pediatric ALL.

Pediatric Intensive Care Unit admission criteria for haemato-oncological patients: a basis for clinical guidelines implementation

Recent advances in supportive care and progress in the development and use of chemotherapy have considerably improved the prognosis of many children with malignancy, thus the need for intensive care admission and management is increasing, reaching about 40% of patients throughout the disease course. Cancer remains a major death cause in children, though outcomes have considerably improved over the past decades. Prediction of outcome for children with cancer in Pediatric Intensive Care Unit (PICU) obviously requires clinical guidelines, and these are not well defined, as well as admission criteria. Major determinants of negative outcomes remain severe sepsis/septic shock association and respiratory failure, deserving specific approach in children with cancer, particularly those receiving a bone marrow transplantation. A nationwide consensus should be achieved among pediatric intensivists and oncologists regarding the threshold clinical conditions requiring Intensive Care Unit (ICU) admission as well as specific critical care protocols. As demonstrated for the critically ill non-oncologic child, it appears unreasonable that pediatric patients with malignancy can be admitted to an adult Intensive Care Unit ICU. On a national basis a pool of refecence institutions should be identified and early referral to an oncologic PICU is warranted.

Hyperglycemia during induction therapy is associated with poorer survival in children with acute lymphocytic leukemia

OBJECTIVES

To investigate whether children with acute lymphocytic leukemia (ALL) who have development of hyperglycemia during induction may have worse relapse-free (RFS) and overall survival (OS) rates.

STUDY DESIGN

A review of 167 children diagnosed with ALL between 1999 to 2002 at Texas Children's Hospital was performed. Blood glucose concentrations during induction therapy were reviewed; patients were assigned to 3 groups: euglycemia (blood glucose < 140 mg/dL), mild hyperglycemia (blood glucose between 140-200 mg/dL), and overt hyperglycemia (blood glucose > 200 mg/dL). RFS and OS among groups were compared by use of Kaplan-Meier and Cox-proportional hazard analyses, adjusting for potential confounding variables.

RESULTS

The median follow-up in survivors was 6 years; there were 18 deaths and 36 relapses. Overt hyperglycemia was seen in 56 (34%) patients. Patients with overt hyperglycemia had poorer RFS (68% +/- [SE] 6.7 vs 85% +/- 3.6, P = .025) and OS (74% +/- 6.1 vs 96% +/- 1.9, P < .0001) at 5 years than their counterparts. Patients with overt hyperglycemia had 6.2 times (95% CI 1.6-24.7, P = .01) greater risk for death, independent of risk group and type of steroid.

CONCLUSIONS

Overt hyperglycemia may be an independent predictor of survival in children with ALL.

Salmonella septic arthritis involving multiple joints in a girl with acute lymphoblastic leukemia at diagnosis

Septic arthritis due to Salmonella has been reported frequently, but multiple joint involvements have rarely been reported in children. A 3-year-old girl presented with Salmonella arthritis involving multiple joints. Laboratory investigations revealed pancytopenia inconsistent with diagnosis of juvenile rheumatoid arthritis or septic arthritis. Bone marrow examination 2 weeks later confirmed the diagnosis of acute lymphoblastic leukemia (ALL). Immunophenotyping studies were consistent with a diagnosis of pre-B ALL. This case illustrates that a delay in the diagnosis may occur when there is an apparent infection focus without classic features of leukemia. Multiple joints involvement of septic arthritis associated with pancytopenia should highlight the possibility of underlying hematologic disorders.

Insights from clinical studies into the role of the MLL gene in infant and childhood leukemia

Translocations involving the Mixed Lineage Leukemia (MLL) gene at 11q23 are found in both acute lymphoblastic leukemia (ALL) and acute myeloblastic leukemia (AML), but have different prognostic implications depending on the phenotype of the leukemia in de novo pediatric cases. The majority of MLL gene rearrangements are associated with infant ALL, and their presence predicts a poor prognosis which worsens with earlier age of presentation. Rearrangements of the MLL gene are found in most cases of infant AML and regardless of age confer an intermediate risk. The treatment of MLL-rearranged ALL in children involves increased intensification of chemotherapy, and infants with ALL are treated with an intensive regimen of ALL- and AML-like chemotherapy, with the proportion of MLL-rearranged cases being responsible for the poor outcome in this age group. The use of DNA microarray analysis to distinguish a particular gene signature for MLL-rearranged leukemias is shedding light on the molecular mechanisms and potential therapeutic targets of these leukemias. It may also prove to have a useful role in both diagnosis and prognosis. This review considers recent advances in our understanding of the role of MLL gene rearrangements in pediatric clinical practice.

Cytosine arabinoside-metabolizing enzyme genes are underexpressed in children with MLL gene-rearranged acute lymphoblastic leukemia

Infant acute lymphoblastic leukemia (IALL) is characterized by mixed lineage leukemia (MLL) gene rearrangements, unique gene expression profiles, poor prognosis, and drug resistance. One exception is cytosine arabinoside (Ara-C) to which IALL cells seem to be more sensitive. We quantified mRNA expression of Ara-C key enzymes in leukemic lymphoblasts from 64 Brazilian ALL children, 15 of them presenting MLL gene rearrangement, and correlated it with clinical and biological features. The diagnosis was based on morphological criteria and immunophenotyping using monoclonal antibodies. MLL gene rearrangements were detected by conventional cytogenetic analysis, RT-PCR and/or fluorescence in situ hybridization. The DCK and HENT1 expression levels were determined by real-time quantitative PCR using SYBR Green I. Relative quantification was made by the standard curve method. The results were analyzed by Mann-Whitney and Fisher exact tests. A P value of <or=0.05 was considered to be statistically significant. DCK and HENT1 expression levels were significantly lower in children with MLL gene-rearranged ALL compared to children with MLL germ line ALL (P = 0.0003 and 0.03, respectively). Our results differ from previous ones concerning HENT1 mRNA expression that observed a higher expression level in MLL gene-rearranged leukemias. In conclusion, the expression of the genes related to Ara-C metabolism was lower in MLL-positive children in the sample studied, suggesting the presence of population differences in the expression profile of these genes especially for HENT1.

Prognostic cytogenetic markers in childhood acute lymphoblastic leukemia

OBJECTIVE

To evaluate children with acute lymphoblastic leukemia (ALL) showing resistance to immediate induction chemotherapy in relation to conventional and advanced cytogenetic analysis.

METHODS

This work was conducted on 63 ALL children (40 males and 23 females) with age range 4.5 months-16 years (mean = 7.76 years). They included 37 cases attained true remission and 26 complicated by failure of remission, early relapse or death. They were subjected to history, clinical examination and investigations including CBC, BM examination, karyotyping, FISH for translocations and flowcytometry for immunophenotyping and minimal residual disease diagnosis.

RESULTS

Cases aged 50.000/mm3 also showed better but non-significant remission rates. Most of the present cases were L2 with better remission compared to other immunophenotypes. Forty informative karyotypes were subdivided into 15 hypodiploid, 10 pseudodiploid, 8 normal diploid and 7 hyperdiploid cases; the best remission rates were noticed among the most frequent ploidy patterns. Chromosomes 9, 11 and 22 were the most frequently involved by structural aberrations followed by chromosomes 5, 12 and 17. Resistance was noted with aberrations not encountered among remission group; deletions involving chromosomes 2p, 3q, 10p and 12q; translocations involving chromosome 5; trisomies of chromosomes 16 and 21; monosomies of 5 and X and inversions of 5 and 11.

CONCLUSION

Some cytogenetic and molecular characterizations of childhood ALL could add prognostic criteria for proper therapy allocation.

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.

Second primary lymphoma or recurrence: a dilemma solved by VDJ rearrangement analysis

A lymphoma patient in remission that develops a second lymphoma is frequently assumed to have had a relapse of the original lymphoma. However, the second lymphoma may instead be a new lymphoma with a different clonal origin. Comparison of histological characteristics alone is insufficient in many cases to distinguish new lymphomas from recurrent lymphomas. In contrast, clonal origins of B-cell lymphomas can be reliably compared by VDJ rearrangement analysis of B-cell IgH genes. Simultaneous lymphomas have similarly been analyzed by this technique to determine whether or not both tumors share a common clonal origin. Application of VDJ rearrangement analysis in clinical research has been important for characterizing mechanisms of lymphoma development. Furthermore, this technique has the potential to improve treatment of lymphoma patients because management of recurrent lymphomas differs from that of new lymphomas.

Stem cell transplantation in follicular lymphoma: progress at last?

Follicular non-Hodgkin's lymphomas usually present in advanced stage and although frequently are chemotherapy-sensitive remain incurable using conventional approaches. Treatment options are evolving rapidly and now include targeted therapies such as monoclonal antibodies. Recent studies, including the EBMTR-sponsored 'CUP Trial' (conventional Chemotherapy, Unpurged autograft, Purged autograft), demonstrate that for patients under age 60 years with recurrent chemotherapy-sensitive disease, autologous stem cell transplantation (ASCT) provides a survival benefit over conventional therapy. Allogeneic stem cell transplantation (alloSCT) has become a more effective option. Although incorporation of TBI into the preparative regimen may increase treatment-related mortality (TRM), relapses appear to be reduced compared to a chemotherapy-alone regimen. Reduced-intensity alloSCT procedures are now being performed at an increasing rate, in part due to a lower risk for TRM. Until more data are available, however, reduced-intensity alloSCT should be considered only in cases where myeloablative conditioning is contra-indicated. There are no clear means for choosing ASCT vs alloSCT, a decision influenced by the amount of residual tumor, disease-responsiveness, degree of marrow involvement and extent of prior chemotherapy. ASCT or alloSCT in first remission remains an investigational procedure. Future considerations include incorporation of novel preparative regimens, in vitro purging techniques, antilymphoma vaccines, post transplant immunotherapy and ex vivo-manipulated donor lymphocyte infusions.

An integrated evaluation of socioeconomic and clinical factors in the survival from childhood acute lymphoblastic leukaemia: a study in Greece

An evaluation of the role of socioeconomic factors in the survival of children with leukaemia, controlling for major clinical prognostic indicators, has been attempted in very few studies and the role of these factors may be different in various cultural settings. Our investigation aims to study the independent role of socioeconomic factors on the prognosis of childhood acute lymphoblastic leukaemia (ALL) in Greece. During a 7-year period (1996-2002) 293 cases of incident ALL were diagnosed and followed up in four Childhood Haematology-Oncology Units, which covered over half of all childhood ALL cases nationwide. At the time of diagnosis, information concerning age, gender, maternal schooling, maternal marital status, sibship size, distance of residence from the treating centre, attendance of day care centre and clinical information was recorded. The influence of these factors on survival was studied by modelling the data through Cox's proportional-hazards regression. After adjustment for clinical prognostic factors, children of mothers who were not currently married, were of low educational level or were living far from the treating centre tended to have lower survival (P-values 0.02, 0.14 and 0.08, respectively). There was also evidence that two factors that are predictive of disease occurrence, that is sibship size and attendance of day care centre, may also predict survival (P-values 0.04 and 0.26, respectively). In conclusion, socioeconomic factors are likely to influence survival from ALL at least in some sociocultural contexts. Moreover, there is evidence that factors that could affect incidence of ALL through modulation of herd immunity may also have prognostic implications for this disease.

Drastic effect of cell density on the cytotoxicity of daunorubicin and cytosine arabinoside

White blood cell count (WBC) is generally accepted as a prognostic risk factor in acute myeloid leukemia (AML) outcome and displays a marked interindividual variation. The dose regimen currently used ignores the size of the tumor burden and the standardization of the dose is generally based on body surface area. In this study we have investigated the effect of cell density on the cytotoxic activity of daunorubicin (DNR) and cytosine arabinoside (AraC) towards HL60 cells and leukemic cells isolated from patients with AML. We demonstrate that drug cytotoxicity decreased with cell density and that apoptosis induction by DNR in isolated leukemic cells was greatly reduced at higher cell density. A marked reduction of the uptake of DNR and AraC in HL60 parental and mitoxantrone resistant cells was observed with increasing cell density. Such a drug depleting effect by cells at high density has been previously described for vincristine, doxorubicin and paclitaxel. By extrapolating the in vitro results to the in vivo situation, one could hypothesize that a high WBC can lower the plasma concentration through high uptake in the tumor burden, leading to a shortage of drug in leukemic blasts. Patients with high WBC might therefore benefit from a dose increase of DNR and/or AraC.

Classification of pediatric acute lymphoblastic leukemia by gene expression profiling

Contemporary treatment of pediatric acute lymphoblastic leukemia (ALL) requires the assignment of patients to specific risk groups. We have recently demonstrated that expression profiling of leukemic blasts can accurately identify the known prognostic subtypes of ALL, including T-cell lineage ALL (T-ALL), E2A-PBX1, TEL-AML1, MLL rearrangements, BCR-ABL, and hyperdiploid karyotypes with more than 50 chromosomes. As the next step toward developing this methodology into a frontline diagnostic tool, we have now analyzed leukemic blasts from 132 diagnostic samples using higher density oligonucleotide arrays that allow the interrogation of most of the identified genes in the human genome. Nearly 60% of the newly identified subtype discriminating genes are novel markers not identified in our previous study, and thus should provide new insights into the altered biology underlying these leukemias. Moreover, a proportion of the newly selected genes are highly ranked as class discriminators, and when incorporated into class-predicting algorithms resulted in an overall diagnostic accuracy of 97%. The performance of an array containing the identified discriminating genes should now be assessed in frontline clinical trials in order to determine the accuracy, practicality, and cost effectiveness of this methodology in the clinical setting.

Innovative strategies in lymphoma therapy

Treatment of malignant non-Hodgkin lymphomas (NHL) in the 21st century has been revolutionized by novel biological agents offering targeted approaches in addition to radio-chemotherapy. Monoclonal antibodies (MoAbs) against lymphatic surface antigens have been effective as monotherapeutic agents, and have already shown their superiority to conventional strategies when combined with chemotherapy. Radioimmunoconjugates are more effective than unlabelled antibodies. Specific inhibitors of neoangiogenesis as well as intracellular signal transduction pathways and antiapoptotic mechanisms have shown their efficacy in phase II studies. Long-term improvement in the setting of minimal residual disease has been observed after vaccination against surface antigens and non-myeloablative allogeneic stem cell transplantation is effective in controlling lymphoma growth. Novel specific antigens are currently identified using expression profiling of lymphomas. In the near future, combinations of biological agents will challenge conventional therapy. These exciting new strategies will improve the success rate in aggressive NHLs and may even challenge the paradigm of incurability of indolent lymphomas.

Clinical applications of BCR-ABL molecular testing in acute leukemia

Recent advances in molecular genetics impact the health care and outcome of patients with acute lymphoblastic leukemia (ALL). BCR-ABL, a common molecular defect in adult ALL, is a valuable tumor marker whose detection influences prognosis and clinical management decisions. Molecular methods such as fluorescence in situ hybridization (FISH), reverse-transcriptase polymerase chain reaction (rtPCR), and real-time quantitative rtPCR can be used to detect the chimeric BCR-ABL gene or its transcripts. These molecular assays improve our ability to measure residual disease and to estimate risk of relapse. On the horizon are gene expression profiles that will likely provide additional information beyond what is obtainable with current clinical and laboratory approaches.

Immature CD34+CD19- progenitor/stem cells in TEL/AML1-positive acute lymphoblastic leukemia are genetically and functionally normal

One important question in stem cell biology of childhood acute lymphoblastic leukemia (ALL) is whether immature CD34+CD19- cells are part of the leukemic cell clone. CD34+CD19- cells from the bone marrow of 9 children with TEL/AML1-positive ALL were purified by flow sorting and subjected to reverse transcriptase-polymerase chain reaction (RT-PCR), fluorescence in situ hybridization, and methylcellulose cultures. In 3 of 8 patients analyzed by RT-PCR, no TEL/AML1-positive cells could be detected in the CD34+CD19- cell fraction. Altogether, the percentage of TEL/AML1-positive cells was low: 1.6% (n = 8; SD 2.2%) by nested real-time RT-PCR and 2.5% (n = 5; SD 2.6%) by fluorescence in situ hybridization. This correlated with the percentage of contaminating CD19+ leukemic cells in the CD34+CD19- cell fraction in 6 control sorts (mean 4.6%, SD 3.6%), indicating that the low levels of leukemic cells detected in the CD34+CD19- cell fraction could be attributed to sorter errors. Methylcellulose cultures in 3 patients provided further evidence that CD34+CD19- cells represent a candidate normal cell population. The clonogenicity of the CD34+CD19- cell fraction was similar to normal progenitors, including growth of primitive granulocyte, erythroid, macrophage, megakaryocyte colony-forming units. Each of 92 colonies from cultures with CD34+CD19- cells tested negative for TEL/AML1. In conclusion, our data support the hypothesis that the leukemia in TEL/AML1-positive childhood ALL originates in a CD19+ lymphoid progenitor. This has many therapeutic implications, eg, for purging of autologous stem cell products, flow cytometric monitoring of minimal residual disease, and targeting immunotherapy against the leukemic cell clone.

Purging of contaminating breast cancer cells from hematopoietic progenitor cell preparations using activation enhanced cell death

Activation enhanced cell death (AECD) involves stimulating cells with growth or activation signals while concurrently blocking calcium influx. In this study, we have evaluated the effect of AECD on human breast cancer cells. MCF-7 or MDA-MB-231 cells treated with Ca2+ influx blockers econazole or ketotifen for 24 h underwent a dose-dependent, irreversible loss of viability, and clonogenicity. Two-hour treatment of these cells with higher concentrations of the drugs also resulted in loss of clonogenicity, but morphological indicators of cell death were apparent only after longer incubation. Loss of clonogenicity could be enhanced almost 10-fold by co-stimulation of the cells with the agonists EGF or bombesin. Econazole was also effective in inducing cell death in multi-drug resistant MCF-7adr cells. Human hemopoietic progenitor cell sensitivity to econazole or ketotifen was evaluated by colony assay. Under conditions resulting in 2.5-3 logs of breast cancer cell loss, 60-70% of hemopoietic progenitors could be recovered. We further evaluated the effect of econazole on breast cancer cells present in mobilized hemopoietic cells obtained from patients undergoing high dose chemotherapy with autologous stem cell support. In six of eight samples evaluated, cytokeratin-positive breast cancer cells could be detected by immunofluorescence microscopy and colony formation. Breast cancer colonies were reduced 60-500-fold or more after exposure to econazole while hemopoietic colonies were typically reduced only 2-fold. In all cases, addition of EGF as an activator either had no evaluable effect or enhanced breast cancer cell loss. We conclude that Ca2+ influx blockade with concurrent EGF stimulation is a promising approach for purging breast cancer cells from hemopoietic progenitor cell preparations.

Neurologic manifestations of hematologic disorders

The subject of hematologic disease is vast, including disorders of cellular component excesses, deficiencies or destruction, and dysfunction. Many of these disorders may lead to neurologic complication. Some of these neurologic conditions are very specific to the hematologic disorder (such as the subacute combined deficiency seen in vitamin B12 deficiency anemia) while others are common to several conditions (hyperviscosity syndrome seen with macroglobulinemia and leukemias). This article reviews some of the more common hematologic diseases and their accompanying neurologic conditions.