Evaluating 3D-printed bioseparation structures using multi-length scale tomography

X-ray computed tomography was applied in imaging 3D-printed gyroids used for bioseparation in order to visualize and characterize structures from the entire geometry down to individual nanopores. Methacrylate prints were fabricated with feature sizes of 500 µm, 300 µm, and 200 µm, with the material phase exhibiting a porous substructure in all cases. Two X-ray scanners achieved pixel sizes from 5 µm to 16 nm to produce digital representations of samples across multiple length scales as the basis for geometric analysis and flow simulation. At the gyroid scale, imaged samples were visually compared to the original computed-aided designs to analyze printing fidelity across all feature sizes. An individual 500 µm feature, part of the overall gyroid structure, was compared and overlaid between design and imaged volumes, identifying individual printed layers. Internal subvolumes of all feature sizes were segmented into material and void phases for permeable flow analysis. Small pieces of 3D-printed material were optimized for nanotomographic imaging at a pixel size of 63 nm, with all three gyroid samples exhibiting similar geometric characteristics when measured. An average porosity of 45% was obtained that was within the expected design range, and a tortuosity factor of 2.52 was measured. Applying a voidage network map enabled the size, location, and connectivity of pores to be identified, obtaining an average pore size of 793 nm. Using Avizo XLAB at a bulk diffusivity of 7.00 × 10-11 m2s-1 resulted in a simulated material diffusivity of 2.17 × 10-11 m2s-1 ± 0.16 × 10-11 m2s-1.

A workflow for the development of template-assisted membrane crystallization downstream processing for monoclonal antibody purification

Monoclonal antibodies (mAbs) are commonly used biologic drugs for the treatment of diseases such as rheumatoid arthritis, multiple sclerosis, COVID-19 and various cancers. They are produced in Chinese hamster ovary cell lines and are purified via a number of complex and expensive chromatography-based steps, operated in batch mode, that rely heavily on protein A resin. The major drawback of conventional procedures is the high cost of the adsorption media and the extensive use of chemicals for the regeneration of the chromatographic columns, with an environmental cost. We have shown that conventional protein A chromatography can be replaced with a single crystallization step and gram-scale production can be achieved in continuous flow using the template-assisted membrane crystallization process. The templates are embedded in a membrane (e.g., porous polyvinylidene fluoride with a layer of polymerized polyvinyl alcohol) and serve as nucleants for crystallization. mAbs are flexible proteins that are difficult to crystallize, so it can be challenging to determine the optimal conditions for crystallization. The objective of this protocol is to establish a systematic and flexible approach for the design of a robust, economic and sustainable mAb purification platform to replace at least the protein A affinity stage in traditional chromatography-based purification platforms. The procedure provides details on how to establish the optimal parameters for separation (crystallization conditions, choice of templates, choice of membrane) and advice on analytical and characterization methods.

Depth filter material process interaction in the harvest of mammalian cells

Upstream advances have led to increased mAb titers above 5 g/L in 14-day fed-batch cultures. This is accompanied by higher cell densities and process-related impurities such as DNA and Host Cell Protein (HCP), which have caused challenges for downstream operations. Depth filtration remains a popular choice for harvesting CHO cell culture, and there is interest in utilizing these to remove process-related impurities at the harvest stage. Operation of the harvest stage has also been shown to affect the performance of the Protein A chromatography step. In addition, manufacturers are looking to move away from natural materials such as cellulose and Diatomaceous Earth (DE) for better filter consistency and security of supply. Therefore, there is an increased need for further understanding and knowledge of depth filtration. This study investigates the effect of depth filter material and loading on the Protein A resin lifetime with an industrially relevant high cell density feed material (40 million cells/ml). It focuses on the retention of process-related impurities such as DNA and HCP through breakthrough studies and a novel confocal microscopy method for imaging foulant in-situ. An increase in loading of the primary-synthetic filter by a third, led to earlier DNA breakthrough in the secondary filter, with DNA concentration at a throughput of 50 L/m2 being more than double. Confocal imaging of the depth filters showed that the foulant was pushed forward into the filter structure with higher loading. The additional two layers in the primary-synthetic filter led to better pressure profiles in both primary and secondary filters but did not help to retain HCP or DNA. Reduced filtrate clarity, as measured by OD600, was 1.6 fold lower in the final filtrate where a synthetic filter train was used. This was also associated with precipitation in the Protein A column feed. Confocal imaging of resin after 100 cycles showed that DNA build-up around the outside of the bead was associated with synthetic filter trains, leading to potential mass transfer problems.

Analysis of fouling and breakthrough of process related impurities during depth filtration using confocal microscopy

Titer improvement has driven process intensification in mAb manufacture. However, this has come with the drawback of high cell densities and associated process related impurities such as cell debris, host cell protein (HCP), and DNA. This affects the capacity of depth filters and can lead to carryover of impurities to protein A chromatography leading to early resin fouling. New depth filter materials provide the opportunity to remove more process related impurities at this early stage in the process. Hence, there is a need to understand the mechanism of impurity removal within these filters. In this work, the secondary depth filter Millistak+ X0HC (cellulose and diatomaceous earth) is compared with the X0SP (synthetic), by examining the breakthrough of DNA and HCP. Additionally, a novel method was developed to image the location of key impurities within the depth filter structure under a confocal microscope. Flux, tested at 75, 100, and 250 LMH was found to affect the maximal throughput based on the max pressure of 30 psi, but no significant changes were seen in the HCP and DNA breakthrough. However, a drop in cell culture viability, from 87% to 37%, lead to the DNA breakthrough at 10% decreasing from 81 to 55 L/m² for X0HC and from 105 to 47 L/m² for X0SP. The HCP breakthrough was not affected by cell culture viability or filter type. The X0SP filter has a 30%-50% higher max throughput depending on viability, which can be explained by the confocal imaging where the debris and DNA are distributed differently in the layers of the filter pods, with more of the second tighter layer being utilized in the X0SP.

Long-term results of the pediatric oncology group studies for childhood acute lymphoblastic leukemia 1984-2001: a report from the children's oncology group

From 1984 to 2001, the Pediatric Oncology Group (POG) conducted 12 acute lymphoblastic leukemia (ALL) studies. Ten-year event-free survival (EFS) for patients >12 months of age with B-precursor ALL on acute leukemia in children 14, 15 and 16 series were 66.7+/-1.2%, 68.1+/-1.4% and 73.2+/-2.1%, respectively. Intermediate dose methotrexate (ID MTX; 1 g/m(2)) improved outcomes for standard risk patients (10-year EFS 77.5+/-2.7% vs 66.3+/-3.1% for oral MTX). Neither MTX intensification (2.5 g/m(2)) nor addition of cytosine arabinoside/daunomycin/teniposide improved outcomes for higher risk patients. Intermediate dose mercaptopurine (1 g/m(2)) failed to improve outcomes for either group. Ten-year EFS for patients with T-cell ALL, POG 8704 and 9404 were 49.1+/-3.1% and 72.2+/-4.7%, respectively. Intensive asparaginase (10-year EFS 61.8 vs 42.7%) and high-dose MTX (5 g/m(2)) (10-year EFS 78.0 vs 65.8%) improved outcomes. There was a non-significant improvement in EFS for infants (10-year EFS 17.7+/-7.2-31.9+/-8.3%). Prognostic indicators for B-precursor ALL were age and WBC at diagnosis, gender, central nervous system disease, DNA index and cytogenetic abnormalities. Only gender was prognostic in T-cell ALL. In infants, WBC and MLL translocation were linked to inferior outcome.

The discovery and optimisation of pyrido[2,3-d]pyrimidine-2,4-diamines as potent and selective inhibitors of mTOR kinase

We describe a novel series of potent inhibitors of the kinase activity of mTOR. The compounds display good selectivity relative to other PI3K-related kinase family members and, in cellular assays, inhibit both mTORC1 and mTORC2 complexes and exhibit good antiproliferative activity.

Microanalysis of amoxicillin, flucloxacillin, and rifampicin in neonatal plasma

Simple and rapid reversed-phase high-performance liquid chromatographic assays with ultraviolet detection have been developed and validated for the determination of amoxicillin, flucloxacillin and rifampicin in neonatal plasma. Plasma samples were either precipitated with perchloric acid (amoxicillin) or methanol (rifampicin) or extracted with methylene chloride (flucloxacillin). Precision coefficients of variation and inaccuracy were less than 15% for all three assays. Only small sample volumes (20-40 microL) were required, making the assays suitable for therapeutic drug monitoring and pharmacokinetic studies in preterm and term neonates. The assays have successfully been applied to analysis of amoxicillin, flucloxacillin and rifampicin in previously published pharmacokinetic studies in neonates.

Amoxicillin Pharmacokinetics in (Preterm) Infants Aged 10 to 52 Days: Effect of Postnatal Age

The pharmacokinetic parameters of amoxicillin were determined in 32 newborn infants aged 10 to 52 days (mean postnatal age, 24.7 +/- 12.4 days) to improve amoxicillin dosing in this age group. Amoxicillin plasma concentrations were determined using reversed-phase high-performance liquid chromatography in surplus plasma samples from routine gentamicin assays. Amoxicillin pharmacokinetic parameters (mean +/- SD) were as follows: first-order elimination constant (K(el)) = 0.27 +/- 0.10 h(-1), volume of distribution corrected for body weight (V/W) = 0.66 +/- 0.27 L/kg, total body clearance corrected for body weight (CL/W) = 0.18 +/- 0.10 Lkg(-1)h(-1), and elimination half-life (t(1/2)) = 3.0 +/- 1.3 hours. Amoxicillin body clearance was approximately twofold greater in our patients compared with published values in younger neonates (mean postnatal age, 0.76 +/- 1.57 days). Simulation studies using the observed amoxicillin pharmacokinetic data suggest an amoxicillin dose of 40 mg/kg administered every 8 hours in infants older than 9 days postnatal age, independent of gestational age and postconceptional age, to achieve satisfactory target plasma amoxicillin concentrations less than 140 mg/L and time above minimum inhibitory concentration of at least 40%. Prospective evaluation of this suggested new dosage regimen is necessary before implementation in the care of ill neonates.

Perforin polymorphism A91V and susceptibility to B-precursor childhood acute lymphoblastic leukemia: a report from the Children's Oncology Group

Perforin plays a key role in the cytotoxicity of natural killer and cytotoxic T cells. Genetic mutations in the perforin gene (PRF1) give rise to approximately 30% cases of familial hemophagocytic lymphohistiocytosis. A frequent polymorphism, A91V (C to T transition at position 272), may impair processing of perforin protein to the active form, and has been suggested to increase susceptibility to childhood acute lymphoblastic leukemia (ALL). To investigate the role of A91V in ALL, we genotyped 2272 children with de novo ALL registered on the Pediatric Oncology Group ALL Classification study P9900 and 655 normal controls. Allele frequencies in the controls showed a very low frequency of the variant allele in blacks, 0.7% compared to 4% in white controls. In light of this, analysis was restricted to a comparison of white cases and controls only. Overall genotype frequencies were similar in white ALL cases and normal white controls (P=0.58), indicating that in contrast to the previous report, A91V polymorphism is not associated with increased risk of childhood ALL. PRF1 A91V frequency was significantly increased in children with BCR-ABL positive ALL (24 vs 8.5%; P=0.0048); however, this observation includes a relatively small number of cases and needs further exploration.

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.

Secondary cytogenetic aberrations in childhood Philadelphia chromosome positive acute lymphoblastic leukemia are nonrandom and may be associated with outcome

Additional chromosomal aberrations occur frequently in Philadelphia chromosome positive (Ph+) acute lymphoblastic leukemia (ALL) of childhood. The treatment outcome of these patients is heterogeneous. This study assessed whether such clinical heterogeneity could be partially explained by the presence and characteristics of additional chromosomal abnormalities. Cytogenetic descriptions were available for 249 of 326 children with Ph+ ALL, diagnosed and treated by 10 different study groups/large single institutions from 1986 to 1996. Secondary aberrations were present in 61% of the cases. Chromosomes 9, 22, 7, 14, and 8 were most frequently abnormal. Most (93%) karyotypes were unbalanced. Three main cytogenetic subgroups were identified: no secondary aberrations, gain of a second Ph and/or >50 chromosomes, or loss of chromosome 7, 7p, and/or 9p, while other secondary aberrations were grouped as combinations of gain and loss or others. Of the three main cytogenetic subgroups, the loss group had the worst event-free survival (P=0.124) and disease-free survival (P=0.013). However, statistical significance was not maintained when adjusted for other prognostic factors and treatment. Karyotypic analysis is valuable in subsets of patients identified by molecular screening, to assess the role of additional chromosomal abnormalities and their correlation with clinical heterogeneity, with possible therapeutic implications.

Clinical heterogeneity in childhood acute lymphoblastic leukemia with 11q23 rearrangements

To assess the clinical heterogeneity among patients with acute lymphoblastic leukemia (ALL) and various 11q23 abnormalities, we analyzed data on 497 infants, children and young adults treated between 1983 and 1995 by 11 cooperative groups and single institutions. The substantial sample size allowed separate analyses according to age younger or older than 12 months for the various cytogenetic subsets. Infants with t(4;11) ALL had an especially dismal prognosis when their disease was characterized by a poor early response to prednisone (P=0.0005 for overall comparison; 5-year event-free survival (EFS), 0 vs 23+/-+/-12% s.e. for those with good response), or age less than 3 months (P=0.0003, 5-year EFS, 5+/-+/-5% vs 23.4+/-+/-4% for those over 3 months). A poor prednisone response also appeared to confer a worse outcome for older children with t(4;11) ALL. Hematopoietic stem cell transplantation failed to improve outcome in either age group. Among patients with t(11;19) ALL, those with a T-lineage immunophenotype, who were all over 1 year of age, had a better outcome than patients over 1 year of age with B-lineage ALL (overall comparison, P=0.065; 5-year EFS, 88+/-+/-13 vs 46+/-14%). In the heterogeneous subgroup with del(11)(q23), National Cancer Institute-Rome risk criteria based on age and leukocyte count had prognostic significance (P=0.04 for overall comparison; 5-year EFS, 64+/-+/-8% (high risk) vs 83+/-+/-6% (standard risk)). This study illustrates the marked clinical heterogeneity among and within subgroups of infants or older children with ALL and specific 11q23 abnormalities, and identifies patients at particularly high risk of failure who may benefit from innovative therapy.

Consensus statements from the Second International Lung Cancer Molecular Biomarkers Workshop: a European strategy for developing lung cancer molecular diagnostics in high risk populations

The Second Molecular Biomarkers Workshop was held at the Roy Castle International Centre for Lung Cancer Research in Liverpool, in June 2001 and it brought together experts in the clinical, epidemiological and molecular-pathology of lung cancer from Europe and the USA, to address issues surrounding the development of a European strategy for early lung cancer detection. The 2001 Workshop Breakout Groups concentrated on the current challenges in the early detection of lung cancer which need to be addressed in the light of the recent surge in interest in many countries for mounting new clinical trials to evaluate the utility of Spiral CT in early lung cancer detection. If population-based trials of CT screening are mounted it will also be a favorable clinical environment in which to evaluate efficiently recent advances in molecular screening and genotyping. The Workshop focused specifically on: a) clinical and molecular biomarkers, b) sputum as an early detection and diagnostic tool, c) validation of molecular markers prior to their use in early detection trials and d) ethical issues that have to be considered in early lung cancer detection trials. A distillation of the Workshop discussions is given in this article.

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.

Relationship of p15 and p16 gene alterations to elevated dihydrofolate reductase in childhood acute lymphoblastic leukaemia

The downstream effects of p15 and p16 gene deletions and loss of transcripts on dihydrofolate reductase (DHFR) were examined in 63 B-precursor (BP) acute lymphoblastic leukaemia (ALL) samples. p15 and/or p16 gene deletions were seen in 6% and 8%, respectively, of BP-ALL samples; however, losses of p15 and/or p16 transcripts were seen in 26 out of 63 (41%) samples. Loss of p15 transcripts (36.5%) exceeded that for p16 (17.5%). For the 26 BP-ALLs that lacked p15 and/or p16 transcripts, only six (23%) exhibited low levels of DHFR by flow cytometry assay with Pt430, a fluorescent anti-folate. Conversely, 18 out of 37 (49%) BP-ALL samples with intact p15 and/or p16 genes and transcripts showed low levels of DHFR (P = 0.04). In p15- and p16-null K562 cells transfected with a tetracycline-inducible p15 cDNA construct, induction of p15 transcripts and protein was accompanied by decreased growth rates, decreased S-phase fraction, decreased retinoblastoma protein phosphorylation, and markedly reduced levels of DHFR transcripts and protein. Collectively, our results suggest that losses of p15 and/or p16 gene expression result in elevated levels of DHFR in BP-ALL in children. However, additional downstream factors undoubtedly also contribute to elevated levels of this enzyme target.

Long-term results of treatment studies for childhood acute lymphoblastic leukemia: Pediatric Oncology Group studies from 1986-1994

This paper presents the long-term results of treatment for children with acute lymphoblastic leukemia (ALL) as conducted by the Pediatric Oncology Group (POG) from 1986 to 1994. The data are presented using standard NCI/Rome risk criteria. The overall event-free survival (EFS) at 5 and 10 years were 70.9% and 67.3% for children with B-precursor ALL, 51.0% and 50.2% for patients with T cell ALL, and 22.4% and 20.9% for infants with ALL. Concomitant biologic studies found that in B-precursor ALL a DNA index (DI) of > or =1.16 and trisomies of both chromosomes 4 and 10 were good prognostic indicators for patients with B-precursor ALL. The traditional prognostic indicators (age and white count), DI and trisomies did not predict outcome in patients with T cell disease. Infants continued to do poorly overall despite more intensive therapy with rotating pairs of chemotherapy. We recommend continued reporting of study results using common risk criteria in order to facilitate comparisons both within and across study groups.

Treatment of children with early pre-B and pre-B acute lymphocytic leukemia with antimetabolite-based intensification regimens: a Pediatric Oncology Group Study

Between May 1987 and January 1991, 1354 patients, 1-21 years old, with standard or poor prognosis B-lineage acute lymphocytic leukemia were treated on the Pediatric Oncology Group Study 8602. One thousand three hundred and twenty-three patients entered remission and 1051 patients were randomized on day 43 to an intensification regimen containing L-asparaginase and intermediate-dose methotrexate (regimen B) or cytarabine and intermediate dose methotrexate (regimen C). After completion of intensification at week 25, all patients received the same maintenance therapy until 3 years from diagnosis. Overall 5-year continuous complete remission (CCR) for regimen B was 72+/-2% (s.e.) and for regimen C, 73+/-2% (P = 0.72 by log-rank analysis). Significant differences between treatments for CCR, testicular, CNS relapses overall or with regard to phenotype (pre-B vs early pre-B), gender, or race were not detected. During intensification, regimen C had significantly more bacterial infections (P = 0.05) and days spent in the hospital (P < 0.001) compared with regimen B, while regimen B had significantly more allergic reactions (P < 0.0001). No significant differences in CCR were noted between patients with pre-B and early pre-B ALL (P = 0.22 stratified by risk group and treatment). This study was unable to detect statistical difference between asparaginase (regimen B) and cytarabine (regimen C) during the intensification phase of therapy in children with B-lineage acute lymphocytic leukemia.

Universal inactivation of both p16 and p15 but not downstream components is an essential event in the pathogenesis of T-cell acute lymphoblastic leukemia

p16/p15 regulate the cell cycle pathway by inhibiting the cyclin Ds-CDK4/6 mediated phosphorylation of pRb. We reported previously that in T-cell acute lymphoblastic leukemia (T-ALL), p16 and p15 were frequently (approximately 70%) inactivated at the DNA level by deletion, mutation, or hypermethylation. Therefore, we hypothesize that inactivation of the cell cycle regulatory pathway may be essential in the pathogenesis of T-ALL, and that the remaining T-ALL with a wild-type p16/p15 gene likely harbor inactivation of these genes at RNA or protein levels. Alternatively, the downstream components of the pathway including CDK4/6, cyclin Ds, and pRb may be deregulated. In 124 primary T-ALLs, we found inactivation of the p16 and p15 genes at the DNA level in 79 (64%) and 64 (52%) samples, respectively. Only 9 of the 45 samples with wild-type p16 expressed p16 protein, whereas the remaining 36 lacked p16 expression at the RNA or protein level. In the 60 samples with an intact p15 gene, only 2 expressed p15 mRNA, and the only one analyzed lacked p15 protein. Overall, the abrogation rates for p16 and p15 at DNA/RNA/protein levels were 93% (115 of 124) and 99% (123 of 124), respectively. Although no alterations were evident in cyclin Ds or CDK4/6, pRb was hyperphosphorylated in the majority of samples investigated. These findings strongly support that both p16 and p15 are specific targets in the deregulation of the cell cycle pathway in T-ALL and that the inactivation of these genes is most likely essential in the pathogenesis of this disease.

Effects of cranial radiation in children with high risk T cell acute lymphoblastic leukemia: a Pediatric Oncology Group report

Contemporary chemotherapy has significantly improved event-free survival among patients with T cell-lineage acute lymphoblastic leukemia (T-ALL). Unlike B-precursor ALL, most investigators are still using cranial radiation (CRT) and are hesitant to rely solely on intrathecal therapy for T-ALL. In this study we assessed the effects of CRT upon event-free survival and central nervous system (CNS) relapses in a cohort of children with high risk features of T cell leukemia. In a series of six consecutive studies (1987-1995) patients were non-randomly assigned their CNS prophylaxis per individual protocol. These protocols were based on POG 8704 which relied on rotating drug combinations (cytarabine/cyclophosphamide, teniposide/Ara-C, and vincristine/doxorubicin/6-MP/prednisone) postinduction. Modifications such as high-dose cytarabine, intermediate-dose methotrexate, and the addition of G-CSF, were designed to give higher CNS drug levels (decreasing the need for CRT), to eliminate epidophyllotoxin (decreasing the risk of secondary leukemia), and to reduce therapy-related neutropenia (pilot studies POG 9086, 9295, 9296, 9297, 9398). All patients included in this analysis qualified for POG high risk criteria, WBC >50000/mm3 and/or CNS leukemia. Patients without CNS involvement received 16 doses of age-adjusted triple intra-thecal therapy (TIT = hydrocortisone, MTX, and cytarabine) whereas patients with CNS disease received three more doses of TIT during induction and consolidation. Patients who received CRT were treated with 2400 cGy (POG 8704) or 1800 cGy (POG 9086 and 9295). CNS therapy included CRT in 144 patients while the remaining 78 patients received no radiation by original protocol design. There were 155 males and 57 females with a median age of 8.2 years. The median WBC for the CRT+ and CRT- patients were 186000/mm3 and 200000/mm3, respectively. CNS involvement at diagnosis was seen in 16% of the CRT+ and 23% of the CRT- groups. The complete continuous remission rate (CCR) was not significantly different for the irradiated vs. non-irradiated groups (P = 0.46). The 3-year event-free survival was 65% (s.e. 6%) and 63% (s.e. 4%) for the non-irradiated vs. the radiated group. However, the 3-year CNS relapse rate was significantly higher amongst patients who did not receive CRT; 18% (s.e. 5%) vs. 7% (s.e. 3%) in the irradiated group (P = 0.012). Our analysis in a non-randomized setting, suggests that CRT did not significantly correlate with event-free survival but omitting it had an adverse effect on the CNS involvement at the time of relapse.

Significance of commonly used prognostic factors differs for children with T cell acute lymphocytic leukemia (ALL), as compared to those with B-precursor ALL. A Pediatric Oncology Group (POG) study

T cell acute lymphocytic leukemia (T-ALL) and B-precursor ALL differ significantly in the clinical characteristics of the patients at presentation and in laboratory-defined characteristics of the leukemic cells. We assessed for pediatric patients with T-ALL the relative importance of prognostic factors previously demonstrated to predict outcome in B-precursor ALL. Presenting clinical and laboratory features were correlated with outcome for 441 children 12 months to 21 years of age with previously untreated T-ALL, registered on the Pediatric Oncology Group (POG) T3 protocol between 1986 and 1992. These T-ALL prognostic factor analyses were then compared to similar analyses for 1993 patients with B-precursor ALL enrolled during the same time period on the POG ALinC 14 protocol. Quantitative interaction between phenotype and each prognostic factor was studied to determine the relative importance of the prognostic factor for each of the two major immunophenotypes. We also analyzed the importance of maturational stage as a T-ALL prognostic factor, using a modified Ludwig definition of maturational stage. We conclude that several of the clinical and laboratory prognostic factors, which are used reliably for B-precursor ALL, are much less predictive in T-ALL (ie age, WBC, consensus risk group, hyperdiploidy, presence of trans- locations and CALLA expression). There was no significant difference between the phenotypes in the prognostic importance of race or gender. Our data demonstrate a significant difference in outcome among the three maturational stages of T-cell ALL, with the intermediate group faring best. Using traditional risk group criteria to stratify patients with T-ALL for therapy may not be appropriate.

Use of alanosine as a methylthioadenosine phosphorylase-selective therapy for T-cell acute lymphoblastic leukemia in vitro

Methylthioadenosine phosphorylase (MTAP) is an important enzyme for the salvage of adenine and methionine and is deficient in a variety of cancers including T-cell acute lymphocytic leukemia (T-ALL). Previously, we reported that the MTAP gene was deleted in over 30% of T-ALL patients at both diagnosis and relapse. We now report that MTAP-primary T-ALL cells are more sensitive to the toxicity of L-alanosine, an inhibitor of de novo AMP synthesis, than are MTAP+ primary T-ALL cells. As measured by [3H]thymidine incorporation, DNA synthesis in all seven MTAP-primary T-ALL cells was inhibited by L-alanosine with a mean IC50 of 4.8+/-5.3 ILM (range, 0.3-11.3 microM). On the other hand, the IC50 for 60% (12 of 20) of MTAP+ primary T-ALL was 19+/-18 microM (range, 1.7-67 microM; P = 0.02), whereas the remaining 40% (8 of 20) had an IC50 of >80 microM4. Furthermore, normal lymphocytes and MTAP+ primary T-ALL cells were rescued from L-alanosine toxicity by the MTAP substrate 5'-deoxyadenosine, but MTAP-T-ALL cells were not. These results indicate that normal cells, which are intrinsically MTAP+, would be protected from L.-alanosine toxicity, whereas MTAP-tumor cells would be killed. Thus, our results support the use of L-alanosine alone or in combination with a salvage agent as a MTAP-selective therapy and therefore lay the foundation for the initiation of clinical trials for the treatment of T-ALL and other MTAP-deficient malignancies with L-alanosine.

Intensive high-dose asparaginase consolidation improves survival for pediatric patients with T cell acute lymphoblastic leukemia and advanced stage lymphoblastic lymphoma: a Pediatric Oncology Group study

This study was designed to test the hypothesis that high-dose asparaginase consolidation therapy improves survival in pediatric patients with T cell acute lymphoblastic leukemia and advanced stage lymphoblastic lymphoma. Five hundred and fifty-two patients (357 patients with T cell acute lymphoblastic leukemia (ALL) and 195 patients with advanced stage lymphoblastic lymphoma) were enrolled in POG study 8704 (T-3). Treatment included rotating combinations of high-dose myelosuppressive chemotherapy agents proven to be effective in T cell ALL in other POG group-wide or local institutional protocols (including vincristine, doxorubicin, cyclophosphamide, prednisone, asparaginase, teniposide, cytarabine and mercaptopurine). After achieving a complete remission (CR), patients were randomized to receive or not receive high-dose intensive asparaginase consolidation (25,000 IU/m2) given weekly for 20 weeks by intramuscular injection. Intrathecal chemotherapy (methotrexate, hydrocortisone and cytarabine) was given to prevent CNS disease, and CNS irradiation was used only for patients with leukemia and an initial WBC of >50,000/microl or patients with active CNS disease at diagnosis. CR was achieved in 96% of patients. The high-dose asparaginase regimen was significantly superior to the control regimen for both the leukemia and lymphoma subgroups. Four-year continuous complete remission rate (CCR) for the leukemia patients was 68% (s.e. 4%) with asparaginase as compared to 55% (s.e. 4%) without. For the lymphoma patients, 4-year CCR was 78% (s.e. 5%) with asparaginase and 64% (s.e. 6%) in the controls. The overall one-sided logrank test had a P value <0.001 favoring asparaginase, while corresponding values were P = 0.002 for ALL and P = 0.048 lymphoblastic lymphoma. Toxicities were tolerable, but there were 18 failures due to secondary malignancies (16 with non-lymphocytic leukemia or myelodysplasia). Neither WBC at diagnosis (leukemia patients) nor lymphoma stage were major prognostic factors. We conclude that when added to a backbone of effective rotating agents, repeated doses of asparaginase during early treatment improve the outcome for patients with T cell leukemia and advanced stage lymphoblastic lymphoma.

Reduced folate carrier gene expression in childhood acute lymphoblastic leukemia: relationship to immunophenotype and ploidy

Reduced folate carrier (RFC) transcripts in human leukemias were measured by a competitive PCR assay. Total RNAs were reverse transcribed and amplified in the presence of competitive templates for RFC and beta-actin. RFC transcripts were normalized to transcripts for beta-actin. In a series of K562 sublines, a approximately 30-fold range of RFC transcripts measured by PCR assay closely agreed with results of Northern analysis and varied in proportion to RFC protein on Western blots and [3H]methotrexate transport. RFC transcripts varied over a 88-fold range in 49 specimens from 48 children with acute lymphoblastic leukemia (ALL). Median RFC transcripts were similar for 15 T-cell and 33 B-precursor ALL samples (RFC/beta-actin = 6.13 x 10(-3) and 7.92 x 10(-3), respectively) and for 41 diagnostic (7.20 x 10(-3)) and 8 relapse (5.58 x 10(-3)) samples. Whereas PCR measurements of RFC transcripts approximated changes in methotrexate transport in B-precursor ALL blasts (n = 10), for T-ALL blasts (n = 12) there was no apparent relationship between these parameters. For hyperdiploid B-precursor blasts (n = 11) with greater than 52 chromosomes and three to five copies of chromosome 21, the median RFC transcript level was approximately 3-fold higher than that for diploid B-precursor blasts. RFC transcripts were also elevated for two of three B-precursor specimens with acquired trisomy 21. Our results suggest that RFC gene expression is far more predictive of methotrexate uptake capacity in B-precursor than T-ALL and that increased copies of chromosome 21 in B-precursor ALL blasts are generally associated with increased RFC transcripts. Hence, the good prognosis for children with hyperdiploid B-precursor ALL treated with antimetabolite-based chemotherapy and the high levels of methotrexate and methotrexate polyglutamates accumulated may, in part, reflect elevated RFC gene expression and capacities for methotrexate transport.

Prognostic significance of sex in childhood B-precursor acute lymphoblastic leukemia: a Pediatric Oncology Group Study

PURPOSE

In childhood B-precursor acute lymphoblastic leukemia (ALL), possible interactions among sex, time, and widely used prognostic factors (age, WBC count, and DNA index) were investigated for the first 5 years after diagnosis.

PATIENTS AND METHODS

All eligible patients aged 1 to less than 22 years, registered between February 1986 and September 1994 in two B-precursor ALL studies from the Pediatric Oncology Group (POG), were included in the analysis. Cutpoints for age (3.0, 5.0, and 10.0 years), WBC count (10, 50, and 100 x 10(9)/L), and DNA index (DI; 1.16) were defined. Four time periods after diagnosis (years 1, 2, 3, and 4 and 5 combined) were selected for the study of prognostic significance over time. The cut-off date for analysis was April 1996.

RESULTS

A total of 3,717 children (2,010 boys and 1,707 girls) were included in the outcome analysis. No major differences between the sexes were observed in age, duration of symptoms before registration, WBC count, hemoglobin level, platelet count, ploidy, presence of CNS disease at diagnosis, or induction failure rate. Event-free survival (EFS) differences between sexes became significantly different from 2 years following diagnosis. At 5 years, in all subsets analyzed, boys fared worse than girls, although not all differences were statistically significant. Major sex differences in EFS were observed in older children (10 to 22 years), in patients with intermediate WBC counts (10 to 50 x 10(9)/ L), and in children who fit both of these subgroups, in whom the 2-year EFS was almost 20% higher in girls than in boys, reaching a 38% difference at 5 years.

CONCLUSION

This study shows an outcome interaction among sex, time, and commonly used prognostic variables. The important sex difference observed at 2 and 5 years suggests that more intensive consolidation and/or maintenance therapy in some boys with B-precursor ALL should be investigated.

Intensive alternating drug pairs after remission induction for treatment of infants with acute lymphoblastic leukemia: A Pediatric Oncology Group Pilot Study

PURPOSE

Infants with acute lymphoblastic leukemia (ALL) often enter remission; however, they have a high rate of relapse. To prevent relapse, infants' tolerance of and benefits from early intensive rotating drug pairs as part of therapy were studied.

METHODS

After prednisone, vincristine, asparaginase, and daunorubicin induction, 12 intensive treatments (ABACABACABAC) were administered in 30 weeks: A, intermediate dose methotrexate (MTX) and intermediate dose mercaptopurine (MP); B, cytosine arabinoside (Ara-C) and daunorubicin (DNR); C, Ara-C and teniposide (VM-26). Triple intrathecal chemotherapy (Ara-C, MTX, and hydrocortisone) was administered for central nervous system prophylaxis. Continuation therapy consisted of weekly MTX and daily MP for a total of 130 weeks of continuous complete remission.

RESULTS

Thirty-three infants (1 year old or younger) with newly diagnosed ALL were treated. Two infants did not respond to induction, 1 died from sepsis during continuation, 1 received a bone marrow transplant, and 24 relapsed. Median time to relapse was 39 weeks. The event-free survival rate at 5 years was 17% (standard error +/- 7.7%). The most significant toxicities occurred during intensification and included fever-neutropenia and bacterial sepsis.

CONCLUSION

Although early intensive rotating therapy is tolerable, the relapse-free survival rate remains poor for infants treated with the schedule on this protocol.

Modelling cure rates using the Gompertz model with covariate information

We extend the modified Gompertz hazard function, first used by Cantor and Shuster for estimation of cure rates from pediatric clinical trials, by including covariate effects. The extended model provides a convenient method for estimation of the cure rate as a function of treatments and covariates.

Myeloperoxidase gene expression in infant leukemia: a Pediatric Oncology Group Study

A high incidence of co-expression of myeloid-associated antigens in infant B-precursor Acute Lymphocytic Leukemia (B-ALL) has been reported, but the significance of this finding is uncertain. To further assess myeloid differentiation and its prognostic significance in this disease, we investigated the frequency of myeloperoxidase (MPO) gene expression in the blast cells from 43 infants with B-ALL registered in a Pediatric Oncology Group (POG) Pilot Study for Treatment of Infant ALL, utilizing a molecular probe for detection of MPO messenger RNA (mRNA) by Northern blot hybridization and a monoclonal antibody to detect MPO-protein by immunohistochemical staining. Sufficient RNA for Northern blot was extracted from 32 bone marrow or blood samples. In two cases, MPO mRNA was determined by a reverse transcriptase-polymerase chain reaction assay and was negative in both cases. MPO-specific transcripts (MPO+) were present in 19 of 34 (56%) samples analyzed. Immunoreactive MPO protein was positive in 13 of the 20 (65%) patients studied. No correlation was found between MPO gene expression and clinical or laboratory features, karyotypic patterns or clinical outcome. The high frequency of MPO gene expression demonstrated in this study suggests that leukemogenic events in many cases of infant B-ALL appear to involve a pluripotent stem cell not yet fully committed to lymphoid differentiation.

Increased frequency of expression of elevated dihydrofolate reductase in T-cell versus B-precursor acute lymphoblastic leukemia in children

The relationships between dihydrofolate reductase (DHFR) levels or methotrexate membrane transport and acute lymphoblastic leukemia (ALL) immunophenotype were evaluated on 51 T-cell and 44 B-precursor ALL specimens from 90 pediatric ALL patients at diagnosis and relapse, using a fluorescent methotrexate analog (PT430) and flow cytometry assay (Matherly et al, Blood 85:500, 1995). For T-cell ALL, 35 of 45 (78%) of newly diagnosed patients' specimens exhibited elevated DHFR relative to DHFR levels in ALL blasts from methotrexate-responsive patients. For 30 of 45 diagnostic T-ALL specimens, DHFR expression was heterogeneous, with up to 3 separate subpopulations covering a 44-fold range; the DHFR-overproducing fractions comprised 10% to 88% of the total blasts. Elevated DHFR was less common in B-precursor ALL at diagnosis, being detected in only 17 of 36 specimens (47%); 11 of these samples exhibited DHFR heterogeneity. Median maximal DHFR levels were fourfold higher in T-cell than B-precursor ALL at diagnosis. Within a particular phenotypic group, there were no correlations between DHFR levels and patient prognostic features, including age, sex, chromosomal abnormalities, white blood cell counts (WBCs), and percentage of S-phase. However, for B-precursor ALL, there was a notably higher fraction of African-American than white patients with elevated DHFR. For patients (both phenotypes) with low WBCs (<50,000/ microL), event-free survival times were significantly shorter for those expressing DHFR above a threshold level than for patients expressing DHFR below this level (P < .016); this relationship was not seen for patients with high WBCs (>50,000/microL). Elevated DHFR was detected in 11 of 14 relapse specimens (5 of 6 T-cell and 6 of 8 B-precursor). Two of five paired relapse specimens (both T-cell) from patients treated with methotrexate exhibited increased DHFR levels over those at diagnosis (2.5- to 5-fold); the fraction of DHFR-overproducing blasts was also increased in 4 of 5 paired relapse specimens (2 B-precursor and 2 T-cell). In contrast to the variations in DHFR, highly impaired methotrexate transport was detected in only 6 of 95 ALL specimens, including both diagnosis and relapse. There was no correlation between phenotype and impaired transport. These data provide further rationale for the use of mechanistically based prognostic factors to complement known biologic or disease-based prognostic indicators in the design of ALL therapy including methotrexate, particularly with patients presenting with low WBCs. The finding of a markedly increased frequency of DHFR overexpression in T-cell over B-precursor ALL suggests that this difference is associated with the poorer prognosis of patients with T-cell ALL treated with standard-dose antimetabolite therapy and implies that higher-dose methotrexate (> or = 1 g/m2) during consolidation therapy may be useful in the treatment of this disease.

Shortened survival after relapse in T-cell acute lymphoblastic leukemia patients with p16/p15 deletions

p16 Alterations were detected in > 60% of 103 primary T-ALL samples. In paired diagnosis-relapse patient samples, 80% of the relapse samples with p16 deletion were deleted at diagnosis. When p16 was homozygously deleted, p15 gene alterations were found in 72% of the diagnosis T-ALL patient samples, increasing significantly to 100% at relapse. Alterations of p18 were not detected. No clinical significance of p15/p16 gene deletion in diagnosis T-ALL was found with respect to white blood cell (WBC) count, incidence of mediastinal mass, rate of relapse, duration of first remission or event-free survival. In relapse T-ALL, however, patients with p16 deletion experienced a significantly shorter duration of post-relapse survival, demonstrating that p16 deletion is clinically significant in T-ALL.

Frequent and selective methylation of p15 and deletion of both p15 and p16 in T-cell acute lymphoblastic leukemia

Frequent deletion of chromosome 9p21 in many cancers has suggested the presence of tumor suppressor genes in this region. Two genes mapping to 9p21, p15 and p16, encode inhibitors for cyclin-dependent kinases 4 and 6. We recently found that in T-cell acute lymphoblastic leukemia (T-ALL), both the p15 and p16 genes are deleted at a high frequency, with p16 gene deletion occurring slightly more frequently than p15 gene deletion. We now show that in addition to deletion, the p15 gene is preferentially hypermethylated at a 5' CpG island, which has been shown previously to be associated with loss of transcription of this gene. The p15 gene was methylated in 38% (17 of 45) of T-ALL patients at diagnosis and in 22% (7 of 32) of patients at relapse. On the other hand, methylation of the p16 gene was a rare event, occurring in 4% (2 of 49) of patients at diagnosis and in none (0 of 30) at relapse. The overall rates of alteration occurring in at least one allele of the p15 gene is 84% at diagnosis and 88% at relapse. These rates are as high as, if not greater than, those for the p16 gene (80% at diagnosis and 74% at relapse). In fact, such alterations involve both alleles in the majority of samples: 76% for p15 and 67% for p16 at diagnosis. All together, more than one-half (56%) of T-ALL samples harbor alterations in both alleles of both p15 and p16. These results lend strong support for a role of both p15 and p16 as tumor suppressors in T-ALL.

Biology and treatment of acute lymphocytic leukemia in children

Biological factors and therapy interact in complex ways to affect prognosis of children with acute lymphocytic leukemia. Therefore, it is important that trials prospectively collect data on potential prognostic factors (such as age, white blood cell count, DNA index, cytogenetics, immunophenotype, central nervous system status, and early treatment response) in all patients. As results of treatment improve, subsequent trials must be large enough to detect small differences in outcomes. Results should be reported after sufficient follow-up, using multivariate analyses, and in a format that permits comparison with outcomes at other centers. Attention to the above will permit an approach to treatment that adapts the intensity of therapy to the risk of relapse.

Comparison of fluorescence in situ hybridization, cytogenetic analysis, and DNA index analysis to detect chromosomes 4 and 10 aneuploidy in pediatric acute lymphoblastic leukemia: a Pediatric Oncology Group study

PURPOSE

Chromosome abnormalities are an important prognostic factor in childhood acute lymphoblastic leukemia (ALL). Recently, a subset of patients with hyperdiploid ALL and trisomy of chromosomes 4 and 10 has been reported to have a very favorable event-free survival. Rapid and accurate detection of these patients will allow them to be treated with highly effective and relatively nontoxic antimetabolite therapy. Because of inherent problems associated with conventional cancer cytogenetics, we examined the efficacy of fluorescence in situ hybridization (FISH) to identify this ALL subgroup.

PATIENTS AND METHODS

Fifty uncultured bone marrow specimens from children with newly diagnosed ALL were examined for chromosomes 4 and 10 aneuploidy with FISH. These results were compared with routine cytogenetics and DNA Index (DI).

RESULTS

Interphase FISH cytogenetics identified the abnormal cell line(s) in all cases in which cytogenetics showed aneuploidy of chromosomes 4 and 10. In cases in which cytogenetics was not informative, FISH identified the presence of an aneuploid chromosome 4 and/or 10 cell line in concordance with the DI.

CONCLUSIONS

FISH interphase cytogenetics can accurately detect chromosome 4 and 10 aneuploidy in leukemic cells. It is a rapid and clinically applicable technique that can reliably identify childhood ALL cases who have trisomy of chromosomes 4 and 10 and who have very favorable event-free survival.

Improved survival for children with B-cell acute lymphoblastic leukemia and stage IV small noncleaved-cell lymphoma: a pediatric oncology group study

PURPOSE

In an effort to improve outcome for children with advanced B-cell malignancies, a treatment plan based on a published regimen that consists of four courses of fractionated cyclophosphamide (cyclo) given with doxorubicin (doxo) and vincristine (VCR) was intensified by alternating with sequential high-dose methotrexate (MTX) and cytarabine (Ara-C), given in conjunction with intrathecal (IT) MTX and Ara-C.

PATIENTS AND METHODS

From October 1986 to October 1992, 133 eligible patients were enrolled: 74 with B-cell (surface immunoglobulin-positive [Slg+] acute lymphoblastic leukemia (B-ALL) and 59 with stage IV small noncleaved-cell lymphoma (SNCCL). The median age was 8 years; there were 103 males and 30 females. Abdominal tumor masses were prominent in 63 cases (33 B-ALL and 30 stage IV SNCCL).

RESULTS

Complete remission (CR) was achieved in 66 B-ALL and 57 stage IV patients (93% overall). At 4 years, the estimated event-free survival (EFS) rate is 65% +/- 8% for patients with B-ALL and 79% +/- 9% for those with stage IV SNCCL. Among patients with CNS involvement, 23 of 36 remain in CR (4-year EFS rate, 64% +/- 13%). Relapses occurred early; only 3 patients relapsed after completion of therapy. Thirteen relapses occurred in the marrow, three in the CNS, and six in other sites. Of 11 CNS-positive patients who relapsed, only two recurred primarily in the CNS.

CONCLUSION

The results of this study indicate that with intensified chemotherapy an increasing potential for cure exists for patients with B-ALL and stage IV SNCCL.

Uniform approach to risk classification and treatment assignment for children with acute lymphoblastic leukemia

PURPOSE

To define more uniform criteria for risk-based treatment assignment for children with acute lymphoblastic leukemia (ALL), the Cancer Therapy Evaluation Program (CTEP) of the National Cancer Institute (NCI) sponsored a workshop in September 1993. Participants included representatives from the Childrens Cancer Group (CCG), Pediatric Oncology Group (POG), Dana-Farber Cancer Institute (DFCI), St Jude Children's Research Hospital (SJCRH), and the CTEP.

METHODS

Workshop participants presented and reviewed data from ALL clinical trials, using weighted averages to combine outcome data from different groups.

RESULTS

For patients with B-precursor (ie, non-T, non-B) ALL, the standard-risk category (4-year event-free survival [EFS] rate, approximately 80%) will include patients 1 to 9 years of age with a WBC count at diagnosis less than 50,000/microL. The remaining patients will be classified as having high-risk ALL (4-year EFS rate, approximately 65%). For patients with T-cell ALL, different treatment strategies have yielded different conclusions concerning the prognostic significance of T-cell immunophenotype. Therefore, some groups/institutions will classify patients with T-cell ALL as high risk, while others will assign risk for patients with T-cell ALL based on the uniform age/WBC count criteria. Workshop participants agreed that the risk category of a patient may be modified by prognostic factors in addition to age and WBC count criteria, and that a common set of prognostic factors should be uniformly obtained, including DNA index (DI), cytogenetics, early response to treatment (eg, day-14 bone marrow), immunophenotype, and CNS status.

CONCLUSIONS

The more uniform approach to risk-based treatment assignment and to collection of specific prognostic factors should increase the efficiency of future ALL clinical research.

Skin microvascular architecture and perfusion studied in human postmastectomy oedema by intravital video-capillaroscopy

Breast cancer treatment often causes chronic arm oedema. Oedema depends on the balance between microvascular filtration and lymph drainage, but little is known about the microvessels in postmastectomy oedema (PMO). We investigated cutaneous capillary density in PMO, since capillary density is one of the factors influencing fluid load on the lymphatic system. Video-capillaroscopy allows the skin microcirculation to be examined in vivo and recorded for later analysis. Patient arm volumes, measured optoelectronically, increased by 30 +/- 13%. The forearm skin of each arm was examined in 7 normal subjects (mean age 22 years) and 15 PMO patients (mean age 61 years). Native capillaroscopy was found to underestimate capillary density. Venous congestion increased the number of capillaries detected by native capillaroscopy by 26-28%. Fluorescein detected 19-27% more capillaries than native capillaroscopy. Using fluorescein, no significant difference in mean capillary density was found between the right (50 mm-2) and left (48 mm-2) arms of normal subjects (p = 0.53). Surprisingly, cutaneous capillary density in the swollen arm (33 mm-2) was not significantly less than in nonswollen arms (35 mm-2) of patients, despite a mean 14% increase in skin area. Capillary density decreased significantly with age. Relative to the volume and area changes, the density results indicated that cutaneous neovascularization had occurred in the swollen arm.

Desmoplastic infantile gangliogliomas: an approach to therapy

Desmoplastic infantile gangliogliomas are massive cystic tumors, typically occurring in the cerebral hemispheres of infants. They are remarkable pathologically for a prominent desmoplasia and, in some cases, for a cellular mitotically active component that can be readily interpreted as a malignant neoplasm. Four children less than 1 year of age were diagnosed with desmoplastic infantile gangliogliomas in the Pediatric Oncology Group infant brain tumor study (Protocol number 8633). All had been diagnosed by their respective institutions as having malignant tumors, i.e., Grade III astrocytoma, malignant meningioma, leptomeningeal fibrosarcoma, and gliosarcoma. All had increased intracranial pressure, and two had seizures. The tumors were extremely large, with one measuring 12 x 9 x 9 cm. None had evidence of metastatic disease. One patient had a gross total resection, and the other three had debulking procedures. All four children were treated with chemotherapy (cyclophosphamide, vincristine, cisplatinum, etoposide) for periods ranging from 12 to 24 months. Of those with postoperative measurable disease, one child had a complete response, one a partial response, and one had stable disease at the conclusion of chemotherapy. No child received radiation therapy. All children are alive with progression-free survivals after diagnosis of more than 36, 42, 48, and 60 months, respectively. Although desmoplastic infantile gangliomas are rare, recognition of this tumor type is essential because, despite their massive size and pathologically malignant appearance, they may have a relatively benign clinical course. If total surgical resection can be achieved, further therapy may not be indicated. In those patients in whom residual disease is present, chemotherapy appears to be an effective form of therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Extended triple intrathecal chemotherapy trial for prevention of CNS relapse in good-risk and poor-risk patients with B-progenitor acute lymphoblastic leukemia: a Pediatric Oncology Group study

PURPOSE

The Pediatric Oncology Group (POG) acute leukemia in childhood (ALinC) 13 study tested two treatment regimens that used different CNS chemoprophylaxis for children older than 12 months with non-T, non-B acute lymphoblastic leukemia (ALL) and with no demonstrable CNS disease at diagnosis.

PATIENTS AND METHODS

With the first regimen, standard (S), six injections of triple intrathecal chemotherapy (TIC), consisting of methotrexate (MTX), hydrocortisone (HC), and cytarabine (ara-C), were administered during intensification treatment and at every-8-week intervals throughout the maintenance phase for 17 additional doses. The second regimen, standard and MTX pulses (SAM), also specified six TICs during intensification, but substituted every-8-week pulses of intermediate-dose parenteral methotrexate (IDM; 1 g/m2) for the 17 maintenance TIC injections, with a low-dose intrathecal (IT) MTX boost administered with the first four maintenance IDM pulses. Otherwise, systemic therapy on regimen SAM was identical to regimen S. There were 1,152 patients randomized to the S and SAM regimens after stratification by risk group (age/leukocyte count) and immunophenotype.

RESULTS

The 5-year probabilities (+/- SE) of an isolated CNS relapse were regimen S: good risk (n = 381), 2.8% +/- 1.3%; poor risk (n = 196), 7.7% +/- 3.2%; good + poor risk (n = 577), 4.7% +/- 1.5%; regimen SAM: good risk (n = 388), 9.6% +/- 2.2%; poor risk (n = 187), 12.7% +/- 4.2%; good + poor risk (n = 575), 10.9% +/- 2.2%. In poor-risk patients, approximately one third of the isolated CNS relapses occurred before preventive CNS therapy was begun at week 9. Hence, regimen S has provided better CNS preventive therapy for both good- and poor-risk patients (P < .001 overall). The difference is statistically significant for good-risk patients (P < .001), but not for poor-risk patients (P = .20). Neither treatment has shown a significant advantage in terms of general outcome.

CONCLUSION

TIC injections extended throughout the intensification and maintenance periods are superior to IDM pulses for prevention of CNS leukemia. Our results with TIC seem comparable with those achieved with other contemporary methods of CNS preventative therapy. Thus, extended TIC affords a reasonable alternative to CNS irradiation plus upfront IT MTX for patients with B-progenitor ALL.

Clinical features and outcome of T-cell acute lymphoblastic leukemia in childhood with respect to alterations at the TAL1 locus: a Pediatric Oncology Group study

Alteration of the TAL1 locus is the most common nonrandom genetic defect in childhood T-cell acute lymphoblastic leukemia (T-ALL). To determine if rearrangements of the TAL1 proto-oncogene confer a distinct leukemic phenotype, we studied leukemic peripheral blood or bone marrow samples from 182 children with newly diagnosed T-ALL enrolled on Pediatric Oncology Group treatment protocols. Forty-eight (26%) of the samples had a local rearrangement of the TAL1 locus. Demographic and clinical features were compared for patient subgroups with and without TAL1 rearrangements. The only clinical correlates that were significantly associated with TAL1 gene rearrangements were higher white blood cell count (P = .017) and higher hemoglobin (P = .007) at diagnosis. Immunophenotypically, samples with altered TAL1 were more likely to be CD2+ (P = .001) and lack CD10 (cALLa) expression (P = .007) than those without the rearrangement. There was a trend toward improved event-free survival (EFS) in patients with TAL1 rearrangements (4-year EFS was 44% +/- 7% for patients without the rearrangements v 59% +/- 11% for those with rearrangements), but the difference was not significant (P = .34). The role of TAL1 in leukemogenesis has yet to be clearly defined, and the prognostic significance of TAL1 gene rearrangements in T-ALL deserves further study.

Trisomy of leukemic cell chromosomes 4 and 10 identifies children with B-progenitor cell acute lymphoblastic leukemia with a very low risk of treatment failure: a Pediatric Oncology Group study

To account for the superior prognosis of hyperdiploid, B-progenitor acute lymphoblastic leukemia (ALL), we investigated the influence of trisomy in 1021 children greater than or equal to 1 year old by recursive partitioning analysis. The patients were treated according to a stratified, randomized study testing antimetabolite-based therapies. Trisomies of several individual chromosomes were associated with a better prognosis in a univariate statistical analysis. Of greater importance, trisomy of both chromosomes 4 and 10 identified a subgroup of patients (n = 180) with an extremely favorable 4-year event-free survival (EFS). Combined trisomy of chromosomes 4 and 10 retained its prognostic significance after stratification of patients by DNA index, age, and leukocyte count. Among patients with a DNA index greater than 1.16, patients with trisomies of both chromosomes 4 and 10 had a 4-year EFS of 96.6% (n = 161, SE = 3.8%), whereas patients with neither or only one of these trisomies had a 4-year EFS of 70.4% (n = 73, SE = 11.5%). All 19 patients with a DNA index less than or equal to 1.16 but with trisomies of chromosomes 4 and 10 remain in remission, suggesting that favorable chromosome trisomy dominates in a situation in which the cellular DNA content of less than or equal to 1.16 predicts a less favorable outcome. We conclude that combined trisomy of chromosomes 4 and 10 independently predicts EFS among children with B-progenitor ALL. Patients within the B-progenitor group who have this feature (about 20% of those with clonal abnormalities) are likely to be cured with antimetabolite-based chemotherapy--an approach that should produce few significant late effects.

t(12;17)(p13;q21) in early pre-B acute lymphoid leukemia

Structural rearrangements involving the short arm of chromosome 12 occur in 10% of cases of childhood acute lymphoid leukemia. The translocation t(12;17)(p13;q21), an uncommon 12p abnormality, was identified in five of 2620 cases (0.2%) successfully karyotyped by the Pediatric Oncology Group or St Jude Children's Research Hospital. All five cases were classified as early pre-B; however, CD10 (common acute lymphoblastic leukemia antigen) was expressed at lower levels than other markers of B-cell lineage. Two cases also expressed the myeloid-associated antigen CD33. Leukemic cells were pseudodiploid in four cases, with an extra chromosome 21 in the fifth case. All of these patients achieved complete remission. Two relapsed during subsequent therapy, and three remain in continuous remission for greater than or equal to 20 months.

t(2;14)(p13;q32): a recurring abnormality in lymphocytic leukemia. A Pediatric Oncology Group study

Chromosome banding studies of 1,411 children with newly diagnosed acute lymphocytic leukemia (ALL) identified two patients with the t(2;14)(p13;q32) chromosome abnormality and a third patient with a complex three-way translocation involving the same breakpoints on chromosomes 2 and 14 but also involving chromosome 12 at band q11. The three cases demonstrated variability of immunophenotypes: one was a T-cell ALL, and two were early pre-B ALLs. All three patients achieved complete remissions and have remained in remission for 14-19 months.

Modes of Feeding in Aggregations of Barnacles and the Shape of Aggregations

The interactions between the form of a barnacle aggregation, its flow environment, and the feeding behavior of each individual was determined in unidirectional flows; both models of barnacle aggregations and live barnacles were used. Hill-shaped aggregations of model barnacles captured significantly more particles than flat aggregations. In general, rows upstream of, and at the peak of, all hill-shaped profiles captured significantly more particles than downstream rows. Living barnacles located at, or upstream of, the peak of natural clusters captured significantly more food particles than did barnacles located downstream. Living barnacles located at, or upstream of, the highest point in a natural cluster fed passively, whereas barnacles downstream of the peak actively swept their cirral net against the flow. Flow was laminar up to the highest point in natural clusters, whereas flow was both reduced and turbulent over the downstream portions. Individual barnacles within a cluster differ in their feeding rates and net energy gains, and therefore differ in their growth such that, in unidirectional flow, the peak of a cluster will shift upstream over time; in oscillating flows, the clusters will develop a symmetrical profile.

Clinical characteristics and treatment outcome of children with acute lymphocytic leukemia and Down's syndrome. A Pediatric Oncology Group study

Of 2947 children with acute lymphocytic leukemia (ALL), treated during three consecutive studies of the Pediatric Oncology Group (1974-1986), 52 (1.8%) had Down's Syndrome (DS). Comparison of clinical and laboratory characteristics showed no significant differences in leukocyte count, racial distribution, sex ratio, platelet count, incidence of mediastinal mass, lymphadenopathy or hepatosplenomegaly, or percentage of blood or bone marrow blasts for children with ALL with or without Down's Syndrome (DS-ALL or NDS-ALL, respectively). However, children with DS-ALL were slightly older at the time of presentation and had higher hemoglobin values. The relative frequency of each major immunophenotype (early pre-B, pre-B, T, or B) was also comparable for patients with or without DS. For this report, treatment regimens were categorized as either conventional (no consolidation therapy) or intensive. Cox regression analysis revealed that the presence of DS, a higher leukocyte count, black race, or age older than 10 years was independently associated with a poorer event-free survival (EFS) for children treated with conventional chemotherapy. However, for the cohort of children who received intensive chemotherapy, DS was no longer an independent risk factor. In fact, event-free survival (EFS) was markedly improved to a level comparable with that observed in the children diagnosed as having NDS-ALL. On the other hand, serious toxicity, requiring interruption of treatment, was significantly more frequent in the intensively treated children with DS compared with similarly treated patients with NDS-ALL, although deaths resulting from toxicity occurred infrequently.

A pilot study of intermediate-dose methotrexate and cytosine arabinoside, "spread-out" or "up-front," in continuation therapy for childhood non-T, non-B acute lymphoblastic leukemia. A Pediatric Oncology Group study

One hundred six children with newly diagnosed non-T-, non-B-cell acute lymphoblastic leukemia (ALL) were treated in a Pediatric Oncology Group (POG) pilot study in which six courses of intermediate-dose methotrexate (MTX) and cytosine arabinoside (Ara-C) (1 g/m2 each) were added to a "backbone" of standard continuation therapy. The dose and sequence of MTX/Ara-C administration were based on a preclinical model that demonstrated synergism between MTX and Ara-C. Poor-risk patients (n = 49) were assigned to "up-front" therapy, in which the MTX/Ara-C courses were administered during the initial 15 weeks of remission. Standard-risk patients (n = 57) were assigned to "spread-out" therapy, in which the MTX/Ara-C courses were interspersed at 12-week intervals within continuation treatment. Toxicity after intermediate-dose MTX/Ara-C, principally neutropenia and fever, was judged significant but manageable. Unexpectedly, the incidence of fever and neutropenia less than 500/mm3 was greater after "spread-out" therapy (38%) than after "up-front" therapy (6%). At 4 years, the Kaplan-Meier estimate of event-free survival (EFS) is 71% (+/- 7%) for standard-risk patients and 53% (+/- 8%) for poor-risk patients. The results of this pilot study support the use of intermediate-dose MTX/Ara-C in additional studies.

High-dose cyclophosphamide-high-dose methotrexate with coordinated intrathecal therapy for advanced nonlymphoblastic lymphoma of childhood: results of a Pediatric Oncology Group study

The Pediatric Oncology Group (POG) investigated a high-dose cyclophosphamide (CPM) high-dose methotrexate (MTX) regimen to determine therapeutic efficacy in confirmed advanced nonlymphoblastic non-Hodgkin's lymphoma (NHL) (stages III and IV) and B-cell acute lymphatic leukemia (B-ALL) in children. Another goal was to determine the comparative effectiveness of shortened maintenance treatment (2 versus 6 courses) in the study population. Systemic induction therapy included vincristine, prednisone, cyclophosphamide, and intermediate-dose MTX with leucovorin rescue. Superimposed intrathecal (IT) therapy included cytosine arabinoside for 2 successive days followed on day 3 by MTX. Intrathecal MTX was given 3 times during induction. At the end of induction, 2 days of triple (hydrocortisone, MTX, and cytosine arabinoside) therapy were given intrathecally (TIT). All patients then received a consolidation course of 4 doses of TIT, 2 doses of cyclophosphamide, and 4 more courses of vincristine and MTX with leucovorin rescue. Patients were then randomized to receive either 2 or 6 cycles of vincristine plus MTX with leucovorin rescue. The TIT was given with each cycle. Complete response rates by histology and Murphy stage (1) were as follows: undifferentiated lymphoma (DUL) stage III, 84/105 (80%): stage IV, 5/12 (42%); and other NHL [primarily large cell lymphoma (LCL)] stage III, 21/28 (75%); stage IV, 2/3 (67%). Event-free survival (EFS) at greater than 2 years was similar for patients with DUL and LCL, i.e., 65 and 61%, respectively. No significant difference in outcome was noted between patient groups receiving 2 or 6 maintenance treatments (p = .76). Treatment was notable for its modest toxicity following the early change to single-dose CPM therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Favorable prognosis associated with hyperdiploidy in children with acute lymphocytic leukemia correlates with extra chromosome 6. A Pediatric Oncology Group study

Pretreatment bone marrow cytogenetic studies were included for 1664 patients with acute lymphoblastic leukemia (ALL) accrued to Pediatric Oncology Group (POG) 8035 laboratory classification study from May 1981 through January 1986. There was a significant difference (P = 0.0001) in distribution of stem-line karyotype (normal, hypodiploid, pseudodiploid, or hyperdiploid) among children with early pre-B, pre-B, or T-cell ALL, with early pre-B patients demonstrating a higher proportion of hyperdiploid karyotypes with modal chromosome numbers greater than 51. Cytogenetic classification of 1216 patients with early pre-B or pre-B ALL evaluable for duration of event-free survival (EFS), with median follow-up of 42 months, showed a significant prolongation of five-year EFS associated with hyperdiploidy greater than 51 (75%; standard error [SE] = 5%) compared with hyperdiploidy 47 to 51 (46%; SE = 7%), hypodiploidy (55%; SE = 11%), and pseudodiploidy (45%; SE = 7%) (P = 0.0001). Five-year EFS was intermediate for patients with normal (58%), constitutionally abnormal (66%), or unsuccessful analyses (66%). The breakpoint defining hyperdiploidy associated with better prognosis was best defined as greater than 51 (P = 0.0002). Of 239 children with hyperdiploid karyotypes, analysis of the contribution of each chromosome to EFS duration showed a significant association between improved EFS and additional chromosome(s) six (P = 0.02). Chromosome translocation was associated with shorter EFS (P = 0.0001).

Isolated thrombocytopenia in children with acute lymphoblastic leukemia: a rare event in a Pediatric Oncology Group Study

To determine how many children with acute lymphoblastic leukemia were initially referred to a pediatric hematologist because of isolated significant thrombocytopenia ([platelet count less than 50,000/mm3] and an otherwise normal complete blood cell count and physical findings), a retrospective review of the Pediatric Oncology Group's charts was undertaken. Review of the records of 2239 children enrolled in the past two acute lymphoblastic leukemia protocols showed that none of these children had significant thrombocytopenia with no other hematologic or physical manifestations of acute lymphoblastic leukemia when they were first seen by the hematologist. The results suggest that routine bone marrow aspiration in the child with isolated thrombocytopenia may be unnecessary to rule out acute lymphocytic leukemia.