Allelic loss of chromosome 1p36 in neuroblastoma is of preferential maternal origin and correlates with N-myc amplification.

Neuroblastomas frequently have deletions of chromosome 1p and amplification of the N-myc oncogene. We analysed 53 neuroblastomas for the N-myc copy number, loss of heterozygosity (LOH) of chromosome 1p36 and the parental origin of the lost alleles. Allelic loss of 1p36 was found in 15 tumours. All N-myc amplified tumours belonged to this subset. In 13/15 tumours with LOH of 1p36 the lost allele was of maternal origin. This non-random distribution implies that the two alleles of the putative neuroblastoma suppressor gene on chromosome 1p36 are functionally different, depending on their parental origin. This is the first evidence as far as we know for genomic imprinting on chromosome 1p.

The human transcriptome map: clustering of highly expressed genes in chromosomal domains.

The chromosomal position of human genes is rapidly being established. We integrated these mapping data with genome-wide messenger RNA expression profiles as provided by SAGE (serial analysis of gene expression). Over 2.45 million SAGE transcript tags, including 160,000 tags of neuroblastomas, are presently known for 12 tissue types. We developed algorithms to assign these tags to UniGene clusters and their chromosomal position. The resulting Human Transcriptome Map generates gene expression profiles for any chromosomal region in 12 normal and pathologic tissue types. The map reveals a clustering of highly expressed genes to specific chromosomal regions. It provides a tool to search for genes that are overexpressed or silenced in cancer.

Risk of second malignancies in long-term survivors of childhood cancer.

INTRODUCTION: Childhood cancer survivors are known to be at increased risk for second malignancies. PATIENTS AND METHODS: The risk of second malignancies was assessed in 1368 5-year survivors of childhood cancer treated in the Emma Children's Hospital AMC in Amsterdam. The median follow-up time was 16.8 years. RESULTS: Sixty two malignancies were observed against 5.4 expected, yielding a standardised incidence ratio (SIR) of 11.2 (95% confidence interval: 8.53-14.4; absolute excess risk: 3.2 per 1000 person-years). New observations were the strongly increased risks of meningiomas (SIR=40) and basal cell carcinomas (SIR=9). Patients whose treatment involved radiotherapy had a 2-fold increased second cancer risk compared to patients with chemotherapy alone. DISCUSSION: The relative risk of second malignancies does not decrease till at least 30 years of follow-up. With aging of the survivor cohort this results in a strong increase of the AER, due to the rising background risk of cancer with age.

Neuroblastoma, Wilms' tumor, and cytomegalovirus.

The possibility that neuroblastomas and Wilms' tumors are induced by cytomegalovirus (CMV) was raised and discussed. A large percentage of patients with these tumors have complement-fixing antibodies against CMV. A hypothesis was presented.

Leukemia after therapy with alkylating agents for childhood cancer.

The risk of leukemia was evaluated in 9,170 2-or-more-year survivors of childhood cancer in the 13 institutions of the Late Effects Study Group. Secondary leukemia occurred in 22 nonreferred individuals compared to 1.52 expected, based on general population rates [relative risk (RR) = 14; 95% confidence interval (CI), 9-22]. The influence of therapy for the first cancer on subsequent leukemia risk was determined by a case-control study conducted on 25 cases and 90 matched controls. Treatment with alkylating agents was associated with a significantly elevated risk of leukemia (RR = 4.8; 95% CI, 1.2-18.9). A strong dose-response relationship was also observed between leukemia risk and total dose of alkylating agents, estimated by an alkylator score. The RR of leukemia reached 23 in the highest dose category. Radiation therapy, however, did not increase risk. Although doxorubicin was also identified as a possible risk factor, the excess risk of leukemia following treatment for childhood cancer appears almost entirely due to alkylating agents.

Tumor-specific down-regulation of the tumor necrosis factor-related apoptosis-inducing ligand decoy receptors DcR1 and DcR2 is associated with dense promoter hypermethylation.

TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) induces apoptosis in a large variety of cancer cells but not in most normal human cells. This feature makes TRAIL, a potential antitumor agent. TRAIL can bind to four different receptors, two pro-apoptotic death receptors (DRs), DR4 and DR5, and two antiapoptotic decoy receptors (DcRs), DcR1 and DcR2. Normal cells express all four of the receptors. The increased TRAIL sensitivity of tumor cells has been postulated to result from the lack of DcR expression. We studied the tumor-specific down-regulation of the TRAIL receptors DcR1 and DcR2, as well as DR4 and DR5, in a group of pediatric tumor cell lines [nine neuroblastoma and three peripheral primitive neuro-ectodermal tumors (PNETs)] and three cell lines from adult tumors. Lack of expression of DcR1 and DcR2 was widespread (13 of the 15 cell lines and 10 of 15, respectively), both in the adult tumor cell lines and in the pediatric tumor lines. DR4 and DR5 were expressed in 8 of 15 and 12 of 15 cell lines, respectively. To understand the tumor-specific down-regulation of the TRAIL receptors, the promoter regions were studied for possible methylation changes of their CpG islands. All normal tissues were completely unmethylated, whereas in the tumor cell lines, we found frequent hypermethylation of the promoter. For DcR1 and DcR2, we found dense hypermethylation in 9 (69%) of 13 and 9 (90%) of 10 of nonexpressing cell lines, respectively. DR4 and DR5 were methylated in 5 (71%) of 7 and 2 (67%) of 3 nonexpressing cell lines, respectively. Treatment with the demethylating agent 5-aza-2'deoxycytidine resulted in partial demethylation and restored mRNA expression. In addition, we performed mutation analysis of the death domains of DR4 and DR5 by sequencing exon 9. Mutations were not present in any of the neuroblastoma or PNET cell lines. A panel of 28 fresh neuroblastoma tumor samples also lacked expression of DcR1 and DcR2 in 85 and 74% of cases, respectively. Hypermethylation was observed in 6 (21%) of 28 for DcR1 and 7 (25%) of 28 for DcR2. DR4 and DR5 were both expressed in 22 of 28 tumors, and no promoter methylation was observed. These data suggest that hypermethylation of the promoters of DcR1 and DcR2 is important in the down-regulation of expression in neuroblastoma and other tumor types.

Allelotype of pediatric rhabdomyosarcoma.

An allelotype covering all autosomes was constructed for the embryonal form of childhood rhabdomyosarcoma (ERMS) in order to identify regions encompassing tumorsuppressor genes (TSG) involved in ERMS. Thusfar most studies were focussed on chromosome 11p15.5, which frequently shows loss of heterozygozity (LOH) in embryonal tumors like RMS and Wilms' tumor (WT). In this study we show that, besides LOH of chromosome 11p15.5 (72%), LOH of chromosome 16q was present in 54% of the tumors analysed. Delineation of these two regions shows that the smallest region of overlap (SRO) for chromosome 11 was between D11S988 and D11S922. This region, estimated to be 7 cM and 3-5 Mb, is also the location of the putative Wilms' tumor WT2 TSG. It contains several genes including IGF2 and potential tumorsuppressor genes like H19 and p57kip2, which might contribute to the carcinogenesis of RMS. Analysis of chromosome 16q LOH defined the SRO between D16S752 and D16S413. LOH of chromosome 16 is also found in other tumors, including WT. Our data suggest that genes involved in the development of RMS and WT may not only be similar for chromosome 11 but also for chromosome 16.

Primary chemotherapy in rhabdomyosarcomas and other malignant mesenchymal tumors of the orbit: results of the International Society of Pediatric Oncology MMT 84 Study.

PURPOSE: The MMT 84 multicentric prospective trial of the International Society of Pediatric Oncology (SIOP) was designed to (1) test the effectiveness of ifosfamide 3 g/m2 on days 1 and 2, vincristine 1.5 mg/m2 on days 1 and 14, and dactinomycin 0.9 mg/m2 on days 1 and 2 (IVA) repeated every 21 days; and (2) reduce late effects of treatment by reserving radiation therapy to the primary site for patients not achieving a complete response (CR) to primary chemotherapy. MATERIALS AND METHODS: Between 1984 and 1989, the MMT 84 study registered 34 children with nonmetastatic rhabdomyosarcomas (RMSs) and other malignant mesenchymal tumors (MMTs) of the orbit in this trial. RESULTS: The 4-year event-free survival rate is 62% +/- 9% (SD) and the 4-year survival rate 86% +/- 7% (SD). A total of 11 local recurrences occurred, 10 among 22 patients treated without initial radiation. Salvage of local failure was achieved in nine of 11 patients with the use of radiation and additional chemotherapy, but three later developed distant metastases and two have died. One isolated regional lymph node failure has occurred, while no patient relapsed with isolated distant metastases. Six of 12 patients who failed are alive with no evidence of disease from 16 to 50 months after relapse. The treatment was well tolerated in all patients, except for one with renal tubular acidosis and one who died of cardiotoxicity. Twelve patients remain in first remission without the use of radiation to the primary tumor from 27 to 84 months. CONCLUSION: Despite a higher incidence of local recurrence when treated by primary chemotherapy, early survival rates were not compromised and a significant number of patients avoided the late effects of radiation. However, longer follow-up is required to assess the ultimate outcome of patients treated in this manner.

Anthracycline-induced clinical heart failure in a cohort of 607 children: long-term follow-up study.

PURPOSE: To determine the early and late cumulative incidence of anthracycline-induced clinical heart failure (A-CHF) after anthracycline therapy in childhood and to identify associated risk factors. PATIENTS AND METHODS: The cumulative incidence of A-CHF and the risk factors of A-CHF were assessed in a cohort of 607 children who had been treated with anthracyclines between 1976 and 1996. For 96% of the cohort, we obtained the clinical status up to at least January 1997. The mean follow-up time was 6.3 years. RESULTS: The cumulative incidence of A-CHF was 2.8%, after a mean follow-up time of 6.3 years and a mean cumulative dose of anthracyclines of 301 mg/m(2). A cumulative dose of anthracycline higher than 300 mg/m(2) was associated with an increased risk of A-CHF (relative risk, 11.8; 95% confidence interval, 1.6 to 59.5) compared with a cumulative dose lower than 300 mg/m(2). The estimated risk of A-CHF increased with time after the start of anthracycline chemotherapy to 2% after 2 years and 5% after 15 years. CONCLUSION: Up to 5% of patients will develop A-CHF 15 years after treatment, and patients treated with a cumulative dose of anthracyclines higher than 300 mg/m(2) are at highest risk for A-CHF. This is thus a considerable and serious problem among these young patients. The findings reinforce the need for strategies for early detection of patients at risk for A-CHF and for the evaluation of other chemotherapeutic possibilities or cardioprotective agents in relation to the survival.

Wilm's tumor with pulmonary metastases at diagnosis: the significance of primary chemotherapy. International Society of Pediatric Oncology Nephroblastoma Trial and Study Committee.

Data from patients with pulmonary metastases (PM) from Wilms' tumor at diagnosis (stage IV) were collected from six European centers. All patients were pretreated with a chemotherapy (CT) regimen consisting of vincristine (VCR), dactinomycin (AD), and Adriamycin (doxorubicin; Adria Laboratories, Columbus, OH). After nephrectomy, local therapy for residual pulmonary disease was considered to avoid whole-lung irradiation. Only four of 36 patients still had multiple inoperable metastases after preoperative CT. Thirty patients survived. Four of them were irradiated. Of the six patients who died, four died of PM, one died of abdominal recurrence, and one of therapy-related disease. Disease-free survival and actuarial survival rates are 83% with a mean follow-up of 4 years postnephrectomy.

Prognostic factors in Ewing's tumor of bone: analysis of 975 patients from the European Intergroup Cooperative Ewing's Sarcoma Study Group.

PURPOSE: To further elaborate on prognostic factors for Ewing's sarcoma of bone and to document improvements in relapse-free survival (RFS) and trends in local therapy over the study period (1977 to 1993). PATIENTS AND METHODS: A retrospective analysis was performed on a combined Gesellschaft Für Pädiatrische Onkologie und Hämatologie/Cooperative Ewing Sarcoma Study and United Kingdom Children's Cancer Study Group/Medical Research Council data set of 975 patients registered with the respective trial offices before the current collaborative European Intergroup Cooperative Ewing's Sarcoma Study trial. Both groups independently undertook studies with similar chemotherapy during the period. RESULTS: The key adverse prognostic factor is metastases at diagnosis (5-year RFS, 22% of patients with metastases at diagnosis v 55% of patients without metastases at diagnosis; P: <.0001). For the group with metastases, there was a trend for better survival for those with lung involvement compared with those with bone metastases or a combination of lung and bone metastases (P: <.0001). In the group of patients with no metastases at diagnosis, multivariate analysis demonstrated that site (axial v other), age-group (< 15 v > or = 15 years), and period of diagnosis had significant influence on RFS (all P: <.005). RFS was superior in the period after 1985 compared with the period before 1985 for nonmetastatic patients (45% v 60%, respectively; P: <.0001) and for metastatic patients (16% v 30%, respectively; P: =.016). Patients who relapsed within 2 years of diagnosis had a less favorable prognosis than patients who relapsed later (5-year survival after relapse, 4% v 23%, respectively; P: <. 0001). There were other changes over the period; in particular, radiotherapy or amputation were more common in the period before 1986, whereas endoprosthetic surgery was widely used in the later period. CONCLUSION: Survival and RFS improved over the period. Prognostic factors are metastases at diagnosis, primary site, and age.

Results of the Sixth International Society of Pediatric Oncology Wilms' Tumor Trial and Study: a risk-adapted therapeutic approach in Wilms' tumor.

PURPOSE: The Sixth International Society of Pediatric Oncology study (SIOP6) concerned Wilms' tumor with favorable histology, preoperatively treated to obtain a high rate of stage I patients, and sought to reduce treatment for patients with stage I and stage II negative nodes (IIN0) tumors and to find better therapy to prevent relapses in stage II positive nodes (IIN1) and stage III patients. PATIENTS AND METHODS: Eligible patients (N = 509) had received four weekly doses of vincristine (VCR) and two courses of dactinomycin (AMD) preoperatively and were assigned after surgery, according to stage and lymph node involvement, to three different prognostic groups, which were to be randomized. Stage I patients (n = 303) received VCR and AMD either for 17 weeks (S) or 38 weeks (L). Stage IIN0 patients (n = 123) received either 20 Gy irradiation (R+) or no irradiation (R-) and received VCR and AMD for 38 weeks. Stage IIN1 and III patients (n = 83) received intensified VCR and AMD (INTVCR) versus VCR, AMD, and Adriamycin (ADRIA; Doxorubicin Farmitalia Carbo Erba, Rueil, Malmaison, France; doxorubicin). Assessment criteria were 2-year disease-free survival (DFS) and 5-year survival (SURV) percentages. A stopping rule was added that took into account abdominal recurrences for the stage IIN0 trial. RESULT: A 52% rate of stage I tumors was obtained, with a low rate of ruptures (7%). The 2-year DFS and 5-year SURV rates according to the different therapeutic groups were stage I, 92% versus 88% (equivalent) and 95% versus 92% for S and L, respectively; stage IIN0, 72% versus 78% (stage equivalent) and 88% versus 85% for R+ and R-, respectively; and stage IIN1 and stage III, 49% versus 74% (P < .029) and 77% versus 80% for INTVCR and ADRIA, respectively, which results in an 82% DFS and 89% SURV rate for the entire trial population. However, six abdominal metastases observed during the first year of follow-up (FU) in the R- group versus none in the R+ group resulted in discontinuation of the stage IIN0 trial. CONCLUSION: Risk-adapted therapy to limit risk of sequelae is possible. More intensive chemotherapy is necessary to prevent abdominal recurrences in nonirradiated stage IIN0 patients treated preoperatively. A three-drug protocol is necessary in stage IIN1 and stage III patients.

Bilateral Wilms' tumor: long-term survival and some epidemiological features.

Sixty-seven children with a bilateral Wilms' tumor (BWT) who were registered to the International Society of Pediatric Oncology (SIOP) nephroblastoma trial and studies 1, 2, and 5, conducted between 1971 and 1980, were analyzed. The overall 10-year survival was 64%. While most deaths due to tumor occurred within 3 years after diagnosis of bilateral disease, five patients died after 3 years (20%), three with synchronous and two with metachronous BWT. The survival rates for the 42 children with synchronous BWT (follow-up time, 6 1/2 to 14 years) and the 25 children with metachronous BWT (follow-up time, 5 to 13 years) were 69% and 56%, respectively. Due to an improvement in the synchronous group, overall survival improved over the years: 47%, 72%, and 70%, in SIOP 1, 2, and 5, respectively. Age at diagnosis and most advanced tumor stage affected prognosis. Children presenting a tumor manifestation before the age of 2 years had better prognosis than older children. This difference is significant in synchronous BWT. Prognosis for children with local stage 1 or 2 was better than for those with local stage 3. Median age at initial presentation in BWT was lower than in unilateral nephroblastoma and lower in metachronous BWT than in synchronous BWT. Young children presenting with unilateral nephroblastoma should have a careful follow-up of the contralateral kidney for at least the next 3 1/2 years, as most contralateral tumors will develop during this period.

A comparison of two short intensive adjuvant chemotherapy regimens in operable osteosarcoma of limbs in children and young adults: the first study of the European Osteosarcoma Intergroup.

PURPOSE: A randomized pilot study was undertaken to assess the acute and chronic toxicities of two short intensive chemotherapy regimens, and to evaluate the feasibility of conservative surgery in this setting. Additional aims were to determine the clinical and radiologic response and the degree of histologic necrosis after chemotherapy. With extension of the study, eventual accrual was sufficient to compare disease-free survival (DFS) and overall survival (OS). PATIENTS AND METHODS: Between July 1983 and December 1986, the European Osteosarcoma Intergroup (EOI) entered 198 eligible patients with classic high-grade extremity osteosarcoma onto a randomized trial that compared doxorubicin (DOX) 25 mg/m2/d times three, intravenous (IV) bolus plus cisplatin (CDDP) 100 mg/m2, 24 hour infusion, every 3 weeks times six; the same combination was preceded 10 days earlier by high-dose methotrexate (HDMTX) 8 g/m2, 6-hour infusion, every 4.5 weeks times four. In the majority of patients (179), chemotherapy was commenced after biopsy; definitive surgery was scheduled at 9 weeks in both groups. RESULTS: Toxicities for both regimens did not differ substantially from those that occurred in other trials of adjuvant chemotherapy in osteosarcoma. Local recurrence (9%) and surgical complications (18%) after conservative surgery were acceptable. With a median follow-up of 53 months, DFS at 5 years is superior (P = .02) for DOX/CDDP, 57% versus 41%, although OS, 64% versus 50%, is not different significantly (P = .10). In a subset of 66 patients for whom pathologic data on the resected specimen were available, DFS (P = .003) and OS (P = .008) were better for those who demonstrated > or = 90% necrosis. CONCLUSION: A brief intensive chemotherapy regimen of DOX/CDDP has produced excellent long-term results, which are similar to those that have been achieved in cooperative group studies of longer, more complex multiagent chemotherapy, and provide the basis for a direct comparison in the next EOI study.

Effectiveness of preoperative chemotherapy in Wilms' tumor: results of an International Society of Paediatric Oncology (SIOP) clinical trial.

The results of a controlled clinical trial of preoperative radiotherapy compared to chemotherapy in patients with nephroblastoma are presented. Of 397 histologically proven cases of Wilms' tumor registered at 34 centers between January 1977 and July 1979, 164 were eligible for the trial and were randomized to receive preoperative radiotherapy and chemotherapy (group R, 76 patients) or preoperative chemotherapy (group C, 88 patients). The results were evaluated in terms of the number of surgical tumor ruptures and of local tumor extent at pathologic examination, reflecting the effectiveness of the preoperative treatment. Survival and recurrence-free survival in the two treatment groups were also taken into account. The stage distribution was comparable in the two groups, with 52% stage I tumors in group R, and 43% in group C. Significant changes in the pathologic pattern were more frequent in group R than in group C (53% versus 17%). From these data it is concluded that preoperative chemotherapy is as good as preoperative radiotherapy in terms of prevention of tumor rupture. In addition, it was shown that 43% of an unselected population of patients with Wilms' tumor could be treated without any radiotherapy when chemotherapy had been given preoperatively.

Indium-111-antimyosin scintigraphy in the early detection of heart damage after anthracycline therapy in children.

PURPOSE: To determine the value of indium-111-antimyosin ((111)In-AM) scintigraphy in the early detection of myocardial damage in children treated with doxorubicin. PATIENTS AND METHODS: Twelve planar scintigrams were made of eight patients (seven children and one young adult; mean age, 12 years). Three scans were obtained before doxorubicin therapy in three patients, and nine scans were obtained during doxorubicin therapy in seven patients. The heart-to-lung ratio (HLR) was calculated. Left ventricular function was assessed by echocardiography before and during therapy by measuring the fractional shortening (FS). RESULTS: The HLR of the three baseline scans was below 1.5, within the normal range for adults. Six of the seven patients whose scans were obtained during chemotherapy had abnormal HLR values (> 1.5). One patient had severe myocyte damage and showed an early increase in the HLR (2.3) after a cumulative doxorubicin dose of 150 mg/m(2). The FS measured by echocardiography was normal throughout therapy, and the final cumulative dose of doxorubicin was 450 mg/m(2). This patient developed fatal clinical heart failure 3 months after completion of chemotherapy. In one patient, who was pretreated with the cardioprotective agent dexrazoxane, the HLR remained within normal limits during therapy. CONCLUSION: (111)In-AM scintigraphy seems to be suitable to detect early myocardial damage after a cumulative doxorubicin dose of 150 mg/m(2 )in children and may be useful for identifying children who are at increased risk of developing cardiac sequelae.

Localized Ewing tumor of bone: final results of the cooperative Ewing's Sarcoma Study CESS 86.

PURPOSE: Cooperative Ewing's Sarcoma Study (CESS) 86 aimed at improving event-free survival (EFS) in patients with high-risk localized Ewing tumor of bone. PATIENTS AND METHODS: We analyzed 301 patients recruited from January 1986 to July 1991 (60% male; median age 15 years). Tumors of volume >100 mL and/or at central-axis sites qualified patients for "high risk" (HR, n = 241), and small extremity lesions for "standard risk" (SR, n = 52). Standard-risk patients received 12 courses of vincristine, cyclophosphamide, and doxorubicin alternating with actinomycin D (VACA); HR patients received ifosfamide instead of cyclophosphamide (VAIA). Tumor sites were pelvis (27%), other central axis (28%), femur (19%), or other extremity (26%). The initial tumor volume was <100 mL in 33% of cases and > or =100 mL in 67%. Local therapy was surgery (23%), surgery plus radiotherapy (49%), or radiotherapy alone (28%). Event-free survival rates were estimated by Kaplan-Meier analyses, comparisons were done by log-rank test, and risk factors were analyzed by Cox models. RESULTS: On May 1, 1999 (median time under study, 133 months), the 10-year EFS was 0.52. Event-free survival did not differ between SR-VACA (0.52) and HR-VAIA (0.51, P =.92). Tumor volume of >200 mL (EFS, 0.36 v 0.63 for smaller tumors; P =.0001) and poor histologic response (EFS, 0.38 v 0.64 for good responders; P =.0007) had negative impacts on EFS. In multivariate analyses, small tumor volumes of <200 mL, good histologic response, and VAIA chemotherapy augured for fair outcome. Six of 301 patients (2%) died under treatment, and four patients (1.3%) developed second malignancies. CONCLUSION: Fifty-two percent of CESS 86 patients survived after risk-adapted therapy. High-risk patients seem to have benefited from intensified treatment that incorporated ifosfamide.

Human megakaryocytes cultured in vitro accumulate serotonin but not meta-iodobenzylguanidine whereas platelets concentrate both.

OBJECTIVE: Thrombocytopenia is the major toxicity of radio-iodinated meta-iodobenzylguanidine (MIBG) therapy in patients with recurrent neuroblastoma. MIBG is taken up in platelets via the serotonin transporter. Given the delayed appearance and long duration of the thrombocytopenia, it seems likely that the precursor megakaryocytes are the primary targets of [131I]MIBG radiotoxicity. MATERIALS AND METHODS: We investigated MIBG and serotonin uptake in cultured human megakaryocytes grown in vitro from CD34(+) cells obtained from bone marrow. RESULTS: With radio-iodinated MIBG, cell-associated radioactivity was negligible, even after prolonged incubations for up to 16 hours. In contrast, after 4 or 16 hours with 10(-8) M [3H]serotonin, 6% or 14% of the added substrate was accumulated in the megakaryocytes. This uptake approached saturation above 10(-7) M and was reduced greater than 90% by coincubation by imipramine. This indicates specific uptake, which was confirmed by fluvoxamine and citalopram. The serotonin reuptake inhibitors fluvoxamine (0.3 nM) and citalopram (1 nM) effectively reduced serotonin uptake to 44% +/- 3% and 30% +/- 9% of the controls, respectively. CONCLUSIONS: Megakaryocytes efficiently retain serotonin in storage granules, as concluded from the consistent reductive effect of tetrabenazine on uptake, retention, and localization (micro-autoradiographic) of serotonin. Thus, serotonin, but not MIBG, is taken up by cultured megakaryocytes.

Genes differentially expressed in medulloblastoma and fetal brain.

Serial analysis of gene expression (SAGE) was used to identify genes that might be involved in the development or growth of medulloblastoma, a childhood brain tumor. Sequence tags from medulloblastoma (10229) and fetal brain (10692) were determined. The distributions of sequence tags in each population were compared, and for each sequence tag, pairwise chi2 test statistics were calculated. Northern blot was used to confirm some of the results obtained by SAGE. For 16 tags, the chi2 test statistic was associated with a P value < 10(-4). Among those transcripts with a higher expression in medulloblastoma were the genes for ZIC1 protein and the OTX2 gene, both of which are expressed in the cerebellar germinal layers. The high expression of these two genes strongly supports the hypothesis that medulloblastoma arises from the germinal layer of the cerebellum. This analysis shows that SAGE can be used as a rapid differential screening procedure.

131I-rose bengal therapy in hepatoblastoma patients.

If conventional treatment modalities have failed in hepatoblastoma patients and no distant metastases can be demonstrated therapy with radionuclide agents can be considered. In 6 patients diagnostic technetium-99m (99mTc)-disofenin and two iodine-131 (131I)-rose bengal scans were made. 2 patients demonstrated specific uptake of disofenin. One of these had a positive scintigram with radiolabelled rose bengal. This patient was subsequently treated with 1.1 GBq 131I-rose bengal. No toxicity was observed. A clear decrease in the level of alpha-fetoprotein indicated a response and demonstrated that this radiopharmaceutical can be used for tumour targeted radiation therapy in selected patients with therapy resistant tumours.