Structural, optical and magnetic properties of γ-irradiated SiO2 xerogel doped Fe2O3.

The paper deals with the structure, morphology and magnetic properties of two different iron concentrations (20 and 33 mol.%) of Fe2O3-SiO2 nanocomposites, prepared by sol-gel technique and exposed to different gamma-irradiation doses (0, 30 and 60 kGy). The nanocomposites were investigated through XRD, TEM, SEM, FTIR and EPR measurements. Superparamagnetic iron (III) oxide nanoparticles with a narrow size distribution, dispersed over the amorphous silica matrix, are assumed to be present in all the samples before and after irradiation. Before irradiation, a lot of γ-Fe2O3 crystalline ferromagnetic nanoparticles are assumed to be formed particularly for sample containing 33 mol.% Fe2O3, while exposing the samples to irradiation results in the transformation of γ- to α-Fe2O3. Iron concentrations and/or irradiation of the samples are assumed to cause changes in the bond angles and/or bond lengths of the structural silicate units within network, as well, the increase of more defect centers induced by irradiation as evident through the variations of the IR bands intensity. The EPR results show both intensity and line width increase with increasing Fe2O3 concentration. The EPR signals for the samples consist of a well defined symmetrical broad signal at g≈2.0 ascribed to antiferromagnetic interactions between the Fe(2+) and Fe(3+) clusters. Condensed clusters of Fe(3+) ions are observed to give rise to a resonance line at g∼2 whose position and width do not depend on the Fe2O3 concentrations. The EPR signal intensity is observed to be significantly decreased in the sample 33 mol.% or stabilized in the sample 20 mol.% by γ-irradiation. This reflects simultaneous spin transformation from the high-spin state of Fe III to the low-spin state of Fe II. As a final point, an effort has been given to found the possibility to use one of these studied nanocomposite materials as candidate for radiation shielding purposes.

Recombinant urate oxidase for the prophylaxis or treatment of hyperuricemia in patients With leukemia or lymphoma.

PURPOSE: To improve the control of hyperuricemia in patients with leukemia or lymphoma, we tested a newly developed uricolytic agent, recombinant urate oxidase (SR29142; Rasburicase; Sanofi-Synthelabo, Inc, Paris, France), which catalyzes the oxidation of uric acid to allantoin, a highly water-soluble metabolite readily excreted by the kidneys. PATIENTS AND METHODS: We administered Rasburicase intravenously, at 0.15 or 0.20 mg/kg, for 5 to 7 consecutive days to 131 children, adolescents, and young adults with newly diagnosed leukemia or lymphoma, who either presented with abnormally high plasma uric acid concentrations or had large tumor cell burdens. Blood levels of uric acid, creatinine, phosphorus, and potassium were measured daily. The pharmacokinetics of Rasburicase, the urinary excretion rate of allantoin, and antibodies to Rasburicase were also studied. RESULTS: At either dosage, the recombinant enzyme produced a rapid and sharp decrease in plasma uric acid concentrations in all patients. The median level decreased by 4 hours after treatment, from 9.7 to 1 mg/dL (P =.0001), in the 65 patients who presented with hyperuricemia, and from 4.3 to 0.5 mg/dL (P =.0001) in the remaining 66 patients. Despite cytoreductive chemotherapy, plasma uric acid concentrations remained low throughout the treatment (daily median level, 0.5 mg/dL). The urinary excretion rate of allantoin increased during Rasburicase treatment, peaking on day 3. Serum phosphorus concentrations did not change significantly during the first 3 days of treatment, decreased significantly by day 4 in patients presenting with hyperuricemia (P =.0003), and fell within the normal range in all patients by 48 hours after treatment. Serum creatinine levels decreased significantly after 1 day of treatment in patients with or without hyperuricemia at diagnosis (P =.0003 and P =.02, respectively) and returned to normal range in all patients by day 6 of treatment. Toxicity was negligible, and none of the patients required dialysis. The mean plasma half-lives of the agent were 16.0 +/- 6.3 (SD) hours and 21.1 +/- 12.0 hours, respectively, in patients treated at dosages of 0.15 or 0.20 mg/kg. Seventeen of the 121 assessable patients developed antibodies to the enzyme. CONCLUSION: Rasburicase is safe and highly effective for the prophylaxis or treatment of hyperuricemia in patients with leukemia or lymphoma.

Carboplatin/ifosfamide window therapy for osteosarcoma: results of the St Jude Children's Research Hospital OS-91 trial.

PURPOSE: To determine the activity of carboplatin/ifosfamide in patients with previously untreated osteosarcoma and to estimate patient outcomes after a multiagent chemotherapy protocol that eliminated cisplatin. PATIENTS AND METHODS: Sixty-nine patients with newly diagnosed, previously untreated osteosarcoma received three cycles of carboplatin (560 mg/m(2) x 1) and ifosfamide (2.65 g/m(2)/d x 3). Assessment of response was evaluated after two (week 6) and three (week 9) chemotherapy cycles. At week 9, histologic response was assessed. Adjuvant therapy comprised two additional carboplatin/ifosfamide cycles, doxorubicin, and high-dose methotrexate. Patients were stratified at enrollment: stratum A, resectable primary tumor without metastases; stratum B, unresectable primary tumor; and stratum C, metastatic disease at diagnosis. Week 6 response was compared with that of a historic group that received only ifosfamide during the initial window evaluation. RESULTS: The clinical and radiographic response rate to three cycles of carboplatin/ifosfamide was 67.7% (95% confidence interval, 55.0% to 78.8%). Compared with the historic population who received only ifosfamide, the combination of carboplatin and ifosfamide reduced the progressive disease rate at week 6 (31.9% v 9%, P: = .003). For patients in stratum A, the 3-year event-free survival and survival were 72.3% +/- 6.7% and 76.4% +/- 6.4%, respectively. Patients who received carboplatin-based therapy had less long-term renal toxicity and ototoxicity. CONCLUSION: This pilot trial suggests that carboplatin/ifosfamide combination chemotherapy has substantial antitumor activity. In the context of a multiagent chemotherapy protocol comprising high-dose methotrexate and doxorubicin, we found that the addition of carboplatin/ifosfamide resulted in patient outcomes comparable to trials using cisplatin-based therapy with less long-term toxicity.

Bone sarcomas of the head and neck in children: the St Jude Children's Research Hospital experience.

BACKGROUND: Bone sarcomas of the head and neck are difficult to resect. The authors reviewed their institutional experience with these tumors to characterize patients' clinical findings and to assess the impact of surgical resection on outcome. METHODS: The records of the 28 patients with bone sarcomas originating in the head and neck treated at St. Jude Children's Research Hospital between March 1962 and January 1998 were reviewed. RESULTS: There were 10 males and 18 females (median age, 12.6 years) each with a single sarcoma: osteosarcoma (18), Ewing sarcoma (7), malignant fibrous histiocytoma (MFH) (2), and fibrosarcoma (1). Primary tumor sites included the maxilla (13), skull (10), mandible (2), and other sites (3). All but one patient with Ewing sarcoma had localized disease at the time of diagnosis. All patients underwent surgery: complete resection, 8; gross total resection, 4; incomplete resection, 14; and biopsy only, 2; 22 also received chemotherapy. Radiotherapy was given to all patients with Ewing sarcoma and to four patients with primary osteosarcoma. Twelve patients survived a median of 8.4 years after diagnosis, 14 died of disease, and 2 died of unrelated causes. Local disease progression was evident in 12 patients (9 with osteosarcoma, 2 with MFH, and 1 with Ewing sarcoma) who died of disease, 9 of whom had the initial treatment of biopsy alone or incomplete resection. Patients with osteosarcoma who had the initial treatment of incomplete resection or biopsy alone were more likely to experience local failure (P = 0.001) and had poorer survival (P = 0.014) than those who underwent complete or gross total resection. CONCLUSIONS: Bone sarcomas of the head and neck are rare among children and most often are localized at the time of diagnosis. Incomplete resection of osteosarcoma is associated with local failure and poor outcome. Although aggressive surgery is essential for the cure of osteosarcoma, its necessity in the treatment of Ewing sarcomas remains controversial.

Outcome of radiation-related osteosarcoma after treatment of childhood and adolescent cancer: a study of 23 cases.

PURPOSE: We analyzed the clinical features and outcome of patients with radiation-associated osteosarcoma treated during the era of contemporary chemotherapy. PATIENTS AND METHODS: The characteristics and outcome of 23 patients (17 males and six females) treated during childhood or adolescence for a solid tumor who later developed osteosarcomas within the radiation field between 1981 and 1996 were reviewed. RESULTS: The median dose of radiation delivered to the first cancer was 47 Gy. Nineteen patients also received chemotherapy. The median time between radiotherapy and the diagnosis of secondary osteosarcoma was 8 years. Histologic slide review showed conventional central osteosarcoma with various differentiation patterns in 21 cases, together with one case of high-grade surface osteosarcoma and one of periosteal osteosarcoma. The sites of involvement were the craniofacial bones in six cases, the first cervical vertebra in one, the girdle bones in seven, and the extremities of long bones in nine. Three patients had metastatic disease at the diagnosis of osteosarcoma. Palliative therapy was administered to seven patients. The aim of treatment was curative for 16 patients, two of whom underwent amputation without further therapy. Intensive chemotherapy regimens were administered to 14 patients before and/or after surgery. Fifteen patients achieved complete surgical remission. Twelve patients were alive and disease-free at a median follow-up duration of 7.5 years. Overall and event-free survivals at 8 years were 50% and 41%, respectively. CONCLUSION: Patients with radiation-related osteosarcoma and resectable lesions can be cured with surgery and intensive preoperative and postoperative chemotherapy.

Early intensification of intrathecal chemotherapy virtually eliminates central nervous system relapse in children with acute lymphoblastic leukemia.

Central nervous system (CNS) relapse has been an obstacle to uniformly successful treatment of childhood acute lymphoblastic leukemia (ALL) for many years. We therefore intensified intrathecal chemotherapy (simultaneously administered methotrexate, hydrocortisone, and cytarabine) for 165 consecutive children with newly diagnosed ALL enrolled in Total Therapy Study XIIIA from December 1991 to August 1994. The 64 patients (39%) who had 1 or more blast cells in cytocentrifuged preparations of cerebrospinal fluid at diagnosis, with or without associated higher-risk features, received additional doses of intrathecal chemotherapy during remission induction and the first year of continuation treatment. Patients with higher-risk leukemia, regardless of cerebrospinal fluid findings, also received additional doses of intrathecal chemotherapy during the first year of continuation treatment. Cranial irradiation was reserved for patients with higher-risk leukemia (22% of the total). The 5-year cumulative risk of an isolated CNS relapse among all 165 patients was 1.2% (95% confidence interval, 0% to 2.9%), whereas that of any CNS relapse was 3.2% (0. 4% to 6.0%). The probability of surviving for 5 years without an adverse event of any type was 80.2% +/- 9.2% (SE). Our results suggest that early intensification of intrathecal chemotherapy will reduce the risk of CNS relapse to a very low level in children with ALL, securing a higher event-free survival rate overall.

Advances in the management of malignancy-associated hyperuricaemia.

Acute tumour lysis syndrome (ATLS) is a metabolic derangement (hyperuricaemia, hyperphosphataemia, hyperkalaemia and hypocalcaemia) associated with lymphoproliferative malignancies. The nature and severity of the metabolic alterations are variable. Major complications are oliguric acute renal failure and delays in initiating chemotherapy. Current management of ATLS includes hydration, alkalinization, diuretics, when indicated, and the reduction of uric acid levels using allopurinol or urate oxidase. Allopurinol inhibits xanthine oxidase, an enzyme that catalyses the conversion of hypoxanthine and xanthine to uric acid. Urate oxidase (Uricozyme), a naturally occurring proteolytic enzyme in many mammals, degrades uric acid to allantoins, which are ten times more soluble than uric acid and easily eliminated by the kidneys. Recently, Sanofi Research isolated a recombinant urate oxidase (SR29142) as a cDNA clone from Aspergillus flavus, expressed in the yeast strain Saccharomyces cerevisiae. Preclinical studies have documented its biological effects as a urolytic enzyme. Twenty-eight healthy male volunteers received SR29142, and a rapid decline of uric acid below measurable levels was seen within 4 h in all patients receiving a dose of more than 0.10 mg kg(-1). Currently, SR29142 is undergoing clinical studies in both Europe and the USA in patients with acute leukaemias or B-cell non-Hodgkin's lymphoma to demonstrate its efficacy and safety in this population of patients at highest risk of developing ATLS or its life-threatening sequelae.

Urate oxidase in prevention and treatment of hyperuricemia associated with lymphoid malignancies.

Standard prophylaxis and treatment of malignancy-associated hyperuricemia in the USA has been allopurinol with vigorous hydration, urinary alkalinization and osmotic diuresis. Urate oxidase, the enzyme that converts uric acid to allantoin (a readily excreted metabolite that has 5- to 10-fold higher solubility than uric acid), is an alternative therapy; however, few published findings support this practice. Between February 1994 and December 1996, we administered non-recombinant urate oxidase (Uricozyme) to 126 children with newly diagnosed non-B cell acute lymphoblastic leukemia (ALL) during the first 5 days of chemotherapy with methotrexate, 6-mercaptopurine or both. Their blood levels of uric acid and other indicators of tumor lysis were measured at diagnosis and during treatment and then compared with findings in 129 similarly treated historical controls who had received allopurinol to control hyperuricemia. Clinical responses to urate oxidase were also determined in eight patients with newly diagnosed B cell ALL or advanced-stage non-Hodgkin lymphoma. Patients treated with urate oxidase had rapid and significantly greater decreases in their blood uric acid levels than did the historical controls (median maximal level during treatment, 2.3 vs 3.9 mg/dl, P < 0.001). They also had lower creatinine (0.6 vs 0.7 mg/dl, P = 0.01) and blood urea nitrogen (11 vs 24 mg/dl, P < 0.001) levels. Similar findings were made in the eight cases of B cell ALL or non-Hodgkin lymphoma. None of the patients required dialysis for acute renal failure. Six (4.5%) of the 134 children given urate oxidase had allergic reactions, manifested primarily by urticaria, bronchospasm and hypoxemia. Thus, non-recombinant urate oxidase is a more effective uricolytic agent than allopurinol but is associated with acute hypersensitivity reactions, even in patients without a history of allergy.

Overt testicular disease at diagnosis is associated with high risk features and a poor prognosis in patients with childhood acute lymphoblastic leukemia.

BACKGROUND: The impact of overt testicular disease on survival was assessed among patients treated at the study institution for childhood acute lymphoblastic leukemia (ALL) over a 15-year period. To the authors' knowledge, the frequency of overt testicular involvement at diagnosis of ALL and its impact on treatment outcome have not been reported previously. METHODS: The medical records of all 651 boys with ALL enrolled on St. Jude Total Therapy Studies X-XIIIA (May 1979 to December 1993) were reviewed to determine the frequency of overt testicular involvement at diagnosis. The log rank test and sequential Cox regression analyses, adjusted for known adverse features, were used to compare event free and overall survival for patients with and without testicular leukemia. A matched-pairs analysis was then conducted for both outcome measures. RESULTS: Thirteen of the 651 male patients (1.9%) presented with overt testicular leukemia. Compared with the other patients, these 13 boys had a significantly higher frequency of infant or adolescent age at diagnosis, hyperleukocytosis, splenomegaly, and mediastinal mass; a poorer 5-year event free survival (38% [95% confidence interval (CI), 15.4-61.4%] vs. 58% [95% CI, 53.6-61.7%], P = 0.06, log rank test); and a significantly poorer 5-year overall survival (37% [95% CI, 14-60.4%] vs. 75% [95% CI, 71.3-78.4%], P = 0.002). The difference in overall, but not event free, survival was supported by sequential Cox regression analyses and by the matched-pairs analysis (P = 0.04). CONCLUSIONS: Overt testicular involvement with leukemia at diagnosis was associated with an adverse survival in boys with ALL. Testicular irradiation may not be necessary in those patients who present with overt testicular involvement. This finding merits prospective evaluation in a larger sample of similarly treated patients.

Relationship between cytotoxicity and site-specific DNA recombination after in vitro exposure of leukemia cells to etoposide.

BACKGROUND: Etoposide, an inhibitor of the normal religation activity of the nuclear enzyme topoisomerase II, can induce a secondary acute myeloid leukemia characterized by site-specific DNA rearrangements. The schedule of drug administration appears to be a clinical risk factor for this devastating treatment complication. PURPOSE: We tested the hypothesis that prolonged exposure of leukemia cells in vitro to low concentrations of etoposide, compared with short exposures to high concentrations, could produce equivalent or greater desired cytotoxic effects, with decreased occurrence of undesired site-specific double-stranded DNA recombinational events (i.e., recombinogenesis). METHODS: We used the frequency of V(D)J (variable-diversity-joining) recombinase-mediated deletions of exons 2 and 3 of the hypoxanthine phosphoribosyltransferase (HPRT) gene as a biomarker of etoposide-induced, nonhomologous, site-specific DNA rearrangement. A polymerase chain reaction-based technique was used to measure exon 2 + 3 deletions in human lymphoid leukemia CCRF-CEM cells 6 days after either 4-hour or 24-hour treatment with etoposide at clinically relevant concentrations. Cytotoxic effects of etoposide (determined by the number of viable cells present in the treated compared with the control [i.e., untreated] cells) were measured 6 days after treatment of the cells. The frequency of the exon 2 + 3 deletion following the two treatment-duration conditions was compared by use of the Mantel-Haenszel statistic. All P values resulted from two-sided tests. RESULTS: Cytotoxicity increased with increasing etoposide concentration and exposure duration, as expected. By day 6, the frequency of exon 2 + 3 deletions was significantly higher (global P value = .0003) after the 4-hour treatment than after the 24-hour treatment, regardless of whether the frequency was assessed at etoposide concentrations achieving equivalent (e.g., 95%) cytotoxicity (14.2 x 10(-7) versus 4.1 x 10(-7) or at equivalent etoposide concentrations (e.g., 1 microM) (10.8 x 10(-7) versus 1.3 x 10(-7). Thus, the ratio of desired cytotoxic to undesired recombinogenic effects was higher with the 24-hour schedule. After the treated cells were subcloned at limiting dilutions, the frequency of the exon 2 + 3 deletion increased from 16.3 x 10(-7) to 4.33 x 10(-3), indicating that the recombinational event is not necessarily lethal. CONCLUSION: For all drug concentrations and levels of cytotoxicity studied in CCRF-CEM cells, there was a greater ratio of cytotoxicity to genetic recombination following prolonged exposure to etoposide than following brief exposure. IMPLICATION: These data suggest that recombinogenesis is not inextricably linked to cytotoxicity. If confirmed in the clinical setting, the use of prolonged dosage schedules may provide a means to decrease the risk of etoposide-induced acute myeloid leukemia without compromising treatment efficacy.

Etoposide achieves potentially cytotoxic concentrations in CSF of children with acute lymphoblastic leukemia.

PURPOSE: Although epipodophyllotoxins are commonly used in contemporary treatment regimens for acute lymphoblastic leukemia (ALL), their potential role in CNS-directed therapy has received little attention. We prospectively studied 20 children during initial remission of ALL and 16 children at relapse to assess CSF penetration of etoposide. METHODS: Simultaneous plasma and CSF concentrations were assessed at a median of 2.8 hours (range, 0.4 to 5.3) after an intravenous (i.v.) or oral dose in 41 paired samples. RESULTS: Etoposide given at 300 mg/m2 i.v. to patients during first remission and at 50 or 25 mg/m2 orally to those in relapse resulted in median CSF levels of 0.175 mumol/L (range, .066 to 2.12), 0.011 mumol/L (range, .004 to .032), and 0.007 mumol/L (range, .003 to .014), respectively. The CSF etoposide concentration was > or = 10 nmol/L in 20 of 20, five of 10, and two of 11 courses following 300 mg/m2 i.v., 50 mg/m2 orally, and 25 mg/m2 orally, respectively, and was positively related to both the concurrent etoposide plasma concentration (R2 = .64) and to dose (R2 = .73). The median ratio of CSF to plasma concentration was 0.30% (range, 0.09% to 3.12%), which was not related to dose, plasma concentration, or time postdose at which samples were obtained, but was positively correlated with the CSF protein concentration (R2 = 0.43, P = .006). Both the absolute etoposide CSF concentrations (P = .008) and the ratio of CSF to plasma concentrations (P = .023) were higher among first-remission patients who had CSF leukemic blasts at diagnosis compared with those without CSF blasts. CONCLUSION: Because etoposide concentrations as low as 10 nmol/L may be cytotoxic in vitro, prolonged daily oral low-dose (50 mg/m2) or conventional i.v. doses of etoposide may contribute to successful CNS-directed therapy in children with ALL.

Epipodophyllotoxin-related acute myeloid leukemia: a study of 35 cases.

To define better the risk of epipodophyllotoxin-related acute myeloid leukemia (AML) after extended follow-up and to assess responses to intensive salvage therapy, all patients who developed this complication after treatment for acute lymphoblastic leukemia (ALL) or non-Hodgkin lymphoma (NHL) in consecutive clinical trials at St Jude Children's Research Hospital from 1979 to 1994 were studied. Cases with 'lineage switch' or 'clonal selection' were excluded. Epipodophyllotoxin-related AML developed in 32 of 1140 patients treated for ALL and in three of 332 treated for NHL; it was a first adverse event in 25 and two cases, respectively. The complication was diagnosed at 12-130 months (median 34 months) after the initiation of treatment with epipodophyllotoxins; all but one of the cases occurred within 73 months, indicating that the risk is negligible after 6 years. The predominant karyotypic feature was 11q23 translocations (71% of cases); 21q22 rearrangements were rare. In a stepwise Cox regression analysis, two factors increased the risk of this complication: weekly or twice weekly administration of epipodophyllotoxins (P < 0.001); and the administration of asparaginase immediately before epipodophyllotoxin therapy (P < 0.001). Initial responses to salvage therapy were comparable to those reported for de novo AML: 92% of the evaluable patients entered complete remission after combination treatment. Single-agent therapy with 2-chlorodeoxyadenosine induced complete or partial remissions in one-half of the patients treated. The long-term survival rate was dismal. Of the 17 evaluable patients treated exclusively with chemotherapy, only one is alive at 84 months, compared to three of 16 patients who underwent bone marrow transplantation (alive at 10, 23 and 73 months). Cases of epipodophyllotoxin-related AML constitute a unique clinical syndrome that will require innovative strategies for cure.

L-asparaginase may potentiate the leukemogenic effect of the epipodophyllotoxins.

The risk for induction of epipodophyllotoxin-related acute myeloid leukemia (AML) depends largely on the schedule of drug administration and, to a lesser degree, the cumulative dose. Concomitant use of other genotoxic drugs, such as alkylating agents and cisplatin, can increase the hazard further. We have treated 154 consecutive higher-risk cases of acute lymphoblastic leukemia in our recent Total Therapy Study XIII with an intensive post-remission regimen of chemotherapy that included etoposide given every other week or less often-a schedule associated with a relatively low cumulative incidence of secondary AML in our Study XI. Unexpectedly, four patients have developed secondary AML at 12 to 23 months from the start of treatment (median, 16 months). The 2-year cumulative risk estimate significantly exceeds that for 185 historical controls in Study XI whose continuation regimen included epipodophyllotoxins every other week: 5.4% (95% confidence interval, 0-11%) compared with 1.1% (0-2.6%), P = 0.046. Compared to patients treated in Study XI, those enrolled in Study XIII receive fewer scheduled doses of epipodophyllotoxin (48 (all etoposide) vs 63 (30 etoposide, 33 teniposide)) but 16 to 19 additional doses of L-asparaginase and eight additional doses of high-dose methotrexate, all within the week preceding etoposide treatment. We attribute the apparently increased rate of secondary AML in Study XIII to the use of L-asparaginase immediately before etoposide administration. On this schedule, the enzyme could increase systemic exposure to etoposide or its catechol metabolites and reduce the ability of cells to repair DNA damage.

Myofibrosarcoma of the head and neck in children.

We have identified a distinctive malignant soft tissue neoplasm that occurred in the head and neck region of six children. Histologically, these neoplasms presented an array of features ranging from low-grade spindle cell to high-grade fibrohistiocytic histologies and often had myoid characteristics. Ultrastructural and immunohistochemical studies indicated that they contained neoplastic myofibroblasts that were variably positive for vimentin (4 positive/4 tested), alpha-smooth muscle actin (4/5), muscle-specific actin (5/5), desmin (2/5), and v-src protein substrate p80/85 (4/5). Three patients died of rapidly progressive unresectable local disease, one died of metastatic and local disease, and two are alive 13 months and 8 years after wide resection. We conclude that these neoplasms form a distinctive subset of pediatric soft tissue sarcomas that display an aggressive clinical behavior, typically with local recurrence, and exhibit features of myofibroblastic differentiation.

Intrauterine monoclonal origin of neonatal concordant acute lymphoblastic leukemia in monozygotic twins.

We report detailed immunological, cytogenetic and molecular evidence for complete identity of the leukemic cell populations in monozygotic female twins with concordant leukemia diagnosed at two months of age. Both infants had early pre-B acute lymphoblastic leukemia with the (11;19)(q23;p13) chromosomal translocation. A common clonal origin of leukemia in these infants was suggested by the finding of identical oligoclonal heavy chain immunoglobulin gene rearrangements. Leukemic cell DNA was examined for 11q23 rearrangements by Southern blotting and restriction fragments of identical size were found in the two cases, in contrast to the diversity of rearrangements observed in other unrelated and nontwinned control infants with t(11;19)(q23;p13). Similar restriction fragments were absent in blood mononuclear DNA from both parents, liver tissue from one twin and remission bone marrow of the other, indicating that the 11q23 rearrangement was acquired and not inherited as a chromosomal abnormality or polymorphism. These findings provide a definitive evidence for intrauterine single cell origin, with twin to twin transmission, of concordant leukemia in this infant twin pair.

Immunologic, cytogenetic, and clinical characterization of childhood acute lymphoblastic leukemia with the t(1;19) (q23; p13) or its derivative.

PURPOSE: To evaluate the immunophenotypes, karyotypes, and clinical features, including treatment responses, of patients with childhood acute lymphoblastic leukemia (ALL) and either a t(1;19)(q23;p13) or a der(19)t(1;19)(q23;p13) translocation. PATIENTS AND METHODS: The lymphoblasts of 45 patients with a balanced translocation, t(1;19) or its derivative form, der(19)t(1;19), were analyzed by cytogenetic and immunologic methods for differences that might suggest distinct subtypes of ALL. This cohort was treated in four consecutive clinical trials with a median overall follow-up duration of 7 years. RESULTS: A pre-B immunophenotype was found in 10 cases with the balanced t(1;19) and 31 with the unbalanced der(19)t(1;19). The four remaining cases, each with a derivative t(1;19), were classified as early pre-B ALL. The characteristic surface antigen profile of the 41 pre-B cases was CD19+/CD10+/CD22+/CD34-/CD20+/-, whether the translocation was balanced or derivative. In contrast to the four early pre-B cases, which had hyperdiploid karyotypes (> 50 chromosomes), the pre-B cases were primarily pseudodiploid. Comparison of presenting clinical and laboratory features, as well as event-free survival, failed to disclose any differences that would warrant separation of pre-B cases with a balanced or derivative translocation. However, neither subgroup responded to therapy as well as patients with early pre-B ALL, each of whom remains in complete remission for > or = 3 years. CONCLUSION: The t(1;19) and the der(19)t(1;19) identify a relatively homogeneous group of patients with pre-B ALL, who can be expected to respond similarly to intensive chemotherapy. The exceptional cases have an early pre-B phenotype with hyperdiploid karyotypes and appear to have favorable prognosis.

Molecular evidence for minimal residual bone marrow disease in children with 'isolated' extra-medullary relapse of T-cell acute lymphoblastic leukemia.

Central nervous system (CNS) relapse confers a poor prognosis in children with acute lymphoblastic leukemia (ALL). It is uncertain whether morphologically undetectable leukemia is present in the bone marrow at the time of CNS relapse, or whether the CNS acts as a 'sanctuary' site to allow reseeding of the marrow at a later time. We examined DNA from bone marrow samples from six patients with T-cell ALL with isolated CNS relapse using sensitive polymerase chain reaction (PCR) assays to detect minimal residual disease. One of these PCR assays was based on amplification of leukemia-specific TCR-delta gene rearrangements, while the other assay relied upon detection of the c-tal deletion. In four patients, where bone marrow samples were taken at the time of CNS relapse, residual disease was detectable in every sample at a level below morphological detection. In addition, three patients had residual disease detected in their subsequent bone marrow when CNS disease was not evident. Our findings, although preliminary, suggest that relapse of leukemia in the CNS reflects resurgence of the disease in the bone marrow that is first detected clinically in the CNS. The concomitant molecular detection of bone marrow leukemia at time of 'isolated' CNS relapse in children with T-cell ALL explains subsequent bone marrow relapse in some of these children, and argues for intensive systemic therapy of these patients.

11q23/MLL rearrangement confers a poor prognosis in infants with acute lymphoblastic leukemia.

PURPOSE: Leukemic cell characteristics were analyzed in infants less than 1 year of age with acute lymphoblastic leukemia (ALL) to determine adverse prognostic factors that might explain the poor prognosis of this group. PATIENTS AND METHODS: Treatment outcomes were analyzed according to the presenting clinical and laboratory features of 30 infants treated between May 1979 and April 1993. A stepwise multivariate regression model was used to identify the most important prognostic indicator with respect to event-free survival. RESULTS: Infant ALL cases were characterized by high presenting leukocyte count (median, 87 x 10(9)/L), increased frequency of CNS leukemia (50%), and blast cells with a CD10- phenotype (67%), myeloid-associated antigen expression (48%), and 11q23/MLL rearrangement (68%). The 11q23/MLL involvement was correlated with age less than 6 months, CD10- phenotype, myeloid-associated antigen expression, and high leukocyte count. Although 11q23/MLL involvement, age less than 6 months, myeloid-associated antigen expression, and female sex were each significantly associated with an inferior treatment outcome, only rearranged 11q23/MLL emerged as an independent predictor of prognosis in multivariate analysis (P = .01). Infants with this genetic abnormality had a 4.7-fold (95% confidence interval, 1.3- to 17.0-fold) increased risk in adverse events compared to other infants. CONCLUSION: The 11q23/MLL involvement of blast cells identifies a major subgroup of infant ALL cases that require an innovative treatment approach. Infants who lack this genetic abnormality have an intermediate prognosis and could be treated accordingly on risk-directed protocols.

Tretinoin toxicity in children with acute promyelocytic leukaemia.

Tretinoin is effective in acute promyelocytic leukaemia in adults. Data about its efficacy and safety in children are limited. We have treated 9 children with tretinoin at 45 mg/m2 per day. Pseudotumour cerebri or hyperleucocytosis occurred in 5 patients. Retinoic acid syndrome was seen in 3 cases. 1 of 2 children who developed hyperleucocytosis, pseudotumour cerebri, and retinoic acid syndrome died despite steroids and mechanical ventilation. Complete remissions with tretinoin alone were achieved in 15 patients. All 8 surviving children received consolidation chemotherapy. Our experience with tretinoin therapy suggests that toxicity is frequent in children.

Low leukocyte counts with blast cells in cerebrospinal fluid of children with newly diagnosed acute lymphoblastic leukemia.

BACKGROUND: Treatment of the central nervous system is crucial to the successful treatment of acute lymphoblastic leukemia in children. The intensity and timing of the therapy are based on the presence or predicted risk of central nervous system leukemia as assessed according to criteria that remain controversial. METHODS: The clinical importance of leukemic blast cells detected in cerebrospinal fluid at the time of diagnosis was evaluated in 351 children with acute lymphoblastic leukemia in a randomized trial of intensive chemotherapy. All patients received intrathecal chemotherapy during the first year. Patients considered to be at high risk of relapse because of their clinical and cytogenetic features also received cranial irradiation and intrathecal chemotherapy one year after remission. Patients were considered to have central nervous system leukemia at diagnosis if they had at least 5 leukocytes per microliter of cerebrospinal fluid, with leukemic blast cells apparent in cytocentrifuged preparations, or cranial-nerve palsy; they received additional intrathecal injections of chemotherapeutic agents and cranial irradiation. Patients were retrospectively classified on the basis of cerebrospinal fluid findings: 291 patients had no detectable blast cells, 42 had fewer than 5 leukocytes per microliter and blast cells, and 18 had central nervous system leukemia as defined above. The clinical characteristics and outcomes of treatment in these groups were analyzed. RESULTS: The five-year probability of survival free of relapses confined to the central nervous system in patients with detectable blast cells and fewer than 5 leukocytes per microliter of cerebrospinal fluid was lower than in patients without blast cells (mean [+/- SE], 87 +/- 13 vs. 96 +/- 2 percent), but was not different from the probability in patients with central nervous system leukemia at diagnosis. All such isolated relapses of leukemia in patients with detectable blast cells occurred during the first year of treatment, before scheduled cranial irradiation. In a multivariate analysis, the presence of cerebrospinal fluid blast cells with fewer than 5 leukocytes per microliter was independently related to the risk of relapse confined to the central nervous system. CONCLUSIONS: Patients with leukemic blast cells in their cerebrospinal fluid are at increased risk for central nervous system relapse when cranial irradiation is delayed. Such patients require intensified central nervous system treatment early in the course of therapy.