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Biomedical subjects

R C Seeger

Publications and source records attributed to R C Seeger.

At least 55 records · Page 3Linked to original sources
PubMed1998

Double-alkylator non-total-body irradiation regimen with autologous hematopoietic stem-cell transplantation in pediatric solid tumors.

PURPOSE: To determine the maximum-tolerated dose (MTD) of cyclophosphamide (CTX) when administered with fixed doses of carboplatin, etoposide, and melphalan (CEM) followed by autologous hematopoietic stem-cell transplantation (HSCT) in children with recurrent or high-risk solid tumors as a consolidation chemotherapy, and to make preliminary observations on efficacy. PATIENTS AND METHODS: Twenty-seven patients with solid tumors between the ages of 2 and 21 years were enrolled. Twenty of 27 had recurrent disease, whereas seven were treated in first remission. Nine were treated with melphalan 50 mg/m2/d for 4 days, carboplatin 300 mg/m2/d for 4 days as a continuous infusion (CI), and etoposide 200 mg/m2/d for 4 days as a CI (level I). CTX 750 mg/m2/d for 4 days was added to this regimen for the next 18 patients (level II). Seven of nine patients at level I and four of 18 at level II received bone marrow (BM) only, while two of nine at level I and 14 of 18 at level II received BM plus peripheral-blood stem cells (PBSC). RESULTS: The median time to reach an absolute neutrophil count (ANC) greater than 500/microl was 12.5 and 10 days for patients who received BM only and BM plus PBSC, respectively. Three cases of grade 3 mucositis, one Candida sepsis, and two transient hypoxemias were the main nonfatal toxicities. No toxic mortality was observed among level I patients. Three of 18 (16%) level II patients, all in second CR, died of transplant-related complications. Median follow-up is 29 months. Nine died of progressive disease (one second malignancy), six relapsed and are alive with disease, and nine are in continuous CR. Among the 15 PNET/Ewing's sarcoma patients, seven are in continuous CR (three of nine in second CR/VGPR, four of six in first CR/VGPR). CONCLUSION: The addition of CTX 3 g/m2 to CEM followed by autologous HSCT as a consolidation therapy resulted in 16% toxic mortality in children with recurrent or high-risk solid tumors. Further CTX dose escalation was aborted. No common nonhematologic toxicity was identified. The event-free survival (EFS) of 66% +/- 19% at 3 years for patients with metastatic PNET/Ewing's sarcoma in first remission is encouraging. However, this is based on only six patients. Both level I and II need further exploration in high-risk pediatric solid tumors in first remission.

Adolescent↗
PubMed1998

Successful treatment of stage III neuroblastoma based on prospective biologic staging: a Children's Cancer Group study.

PURPOSE: To identify a biologically favorable and unfavorable subset of patients with Evans stage III neuroblastoma and to determine whether treatment stratification would improve the event-free survival (EFS) for high-risk patients and maintain excellent EFS for the lower-risk patients. PATIENTS AND METHODS: Risk stratification was performed by age, MYCN gene copy number, Shimada histopathologic classification, and serum ferritin level. Lower-risk patients were treated on the less intensive Children's Cancer Group (CCG)-3881, whereas high-risk patients were treated on CCG-3891, which included more intensive multimodality therapy and, in some cases, autologous bone marrow transplantation (ABMT). RESULTS: Of 228 Evans stage III patients entered onto the study, 92% also met the definition of International Neuroblastoma Staging System (INSS) stage 3. One hundred forty-three patients met the lower-risk criteria, which included 89 patients less than 1 year of age and 54 patients 1 year of age or greater, and favorable biology, whereas 85 patients were 1 year of age or greater and biologically unfavorable. Biologically unfavorable patients 1 year of age or greater who underwent gross surgical resection had improved survival, whereas the outcome of infants or biologically favorable older patients did not change according to resection. The EFS rate at 4 years was 100% for the patients with favorable biology of any age, 90% for those less than 1 year of age but with at least one unfavorable characteristic, and 54% for Evans stage III patients 1 year of age or greater with unfavorable biology. Age, ferritin level, MYCN copy number, Shimada histopathology, primary site, and intraspinal extension were significant univariate prognostic factors for all patients, but only MYCN copy number and age were independent factors in multivariate analyses. CONCLUSION: The excellent survival of the biologically favorable group and the historically improved EFS of the biologically unfavorable group suggest that biologic staging should be used to define the prognosis and treatment of stage III neuroblastoma.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

A phase I/IB trial of murine monoclonal anti-GD2 antibody 14.G2a plus interleukin-2 in children with refractory neuroblastoma: a report of the Children's Cancer Group.

BACKGROUND: The murine monoclonal antibody (MoAb) 14.G2a recognizes GD2, a disialoganglioside expressed in tumors of neuroectodermal origin, and facilitates antibody dependent cellular cytotoxicity (ADCC) in vitro. When given in vivo, interleukin-2 (IL-2) can increase ADCC by enhancing the activity and number of circulating lymphocytes. METHODS: Thirty-three pediatric patients with GD2 positive malignancies, ranging in age from 2 to 17 years (median, 9.9 years), received IL-2 and 14.G2a in this Phase I/IB study of the Children's Cancer Group (CCG) and were monitored for toxicities and response to therapy. Seven of these patients also received granulocyte-macrophage-colony stimulating factor. RESULTS: The maximum tolerated dose (MTD) of 14.G2a with IL-2 was 15 mg/m2/day. The most prevalent Grade 3-4 toxicities were generalized pain (n = 14 [42%]) and fever without documented infection (n = 17 [52%]). IL-2 was thought to be the causative agent in most cases of fever. Toxicities attributed to 14.G2a included pain, allergic or anaphylactic reactions, and rash. Human antimouse antibodies were demonstrated in 9 of 21 evaluated patients. One patient with neuroblastoma had a partial response, and one patient with osteosarcoma had a complete response. Immunocytology demonstrated that the number of neuroblastoma cells in bone marrow decreased in three patients. CONCLUSIONS: The murine MoAb 14.G2a was well tolerated at the MTD and appeared to have some antitumor activity. Further development of this approach will involve additional engineered forms of the antibody as well as testing in the adjuvant and minimal residual disease setting.

Adjuvants, Immunologic↗
PubMed1997

Neuroblastoma in adults and adolescents: an indolent course with poor survival.

BACKGROUND: Neuroblastoma rarely occurs in adults, and less than 10% of cases occur in patients older than 10 years. It has been suggested that the behavior of this disease may be different in older patients than in young children. The purpose of this study was to investigate the presentation, biologic features, and outcome of adolescent and adult patients with neuroblastoma to define differences from childhood neuroblastoma. METHODS: Medical record and pathology reviews were conducted for 16 patients age 13 years or older (13-33 years) at diagnosis who presented with neuroblastoma at the University of California-San Francisco (UCSF) during the period 1968-1995 (patients with intracerebral tumors, esthesioneuroblastoma, or ganglioneuroma were excluded). Six of these patients received their original diagnosis at UCSF, and the others were referred after diagnosis. The survival for the same period for all neuroblastoma patients ages 13-18 years (n = 38) registered in the Children's Cancer Group (CCG) was compared with the survival for those ages 1-13 years (n = 1912). Three of the UCSF patients were enrolled in CCG studies. RESULTS: Biologic characteristics observed in adolescents and adults differed from those observed in younger patients. In the UCSF population, only 6 of 15 tested patients age 13 or older had elevated urinary catecholamines, and 0 of 6 tested patients had MYCN amplification. There were two patients with Stage I disease, three with Stage II, two with Stage III, and nine with Stage IV. Primary sites were adrenal, pelvic, and retroperitoneal in four cases each; mediastinal in two cases; and paraspinal in two cases. Metastases in nine patients at diagnosis were observed in bone in five; in bone marrow in four; in lymph nodes in three; in the liver in two; and in the pleura, breast, and dura in one patient each. 131I-metaiodobenzylguanidine uptake was observed in 9 of 11 patients. Initial treatment included surgery for 13 of 16 patients, chemotherapy for 10 of 16, radiation therapy for 7 of 16, and autologous bone marrow transplantation for 1 of 16. Relapses occurred in 15 of 16 patients and death in 13 of 16, with overall survival 30% 5 years after diagnosis. Only 1 patient currently remains free of clinical disease 24 months after diagnosis. Several of these patients had long courses from diagnosis to death, with multiple recurrences and/or chronic, persistent disease. In the CCG data base, 76% of patients ages 13-18 years had metastatic disease at diagnosis. In this group, only 1 of 32 had MYCN amplification. The actuarial survival of all CCG patients ages 13-18 years was 7% at 5 years and 4% at 10 years, whereas that for patients ages 1-13 years was 30% at 5 years and 23% at 10 years. CONCLUSIONS: Neuroblastoma in adolescents and adults has different biologic characteristics and a longer course than in children; nevertheless, ultimately the outcome is poor regardless of stage. A much more aggressive or innovative therapeutic approach is needed for these patients.

3-Iodobenzylguanidine↗
PubMed1997

Drug resistance in human neuroblastoma cell lines correlates with clinical therapy.

To determine if neuroblastoma acquires a sustained drug-resistant phenotype from patient exposure to therapy, we studied neuroblastoma cell lines established at different points of therapy: at diagnosis prior to therapy, at progressive disease after induction therapy and at relapse after intensive chemoradiotherapy and bone marrow transplantation (post-BMT). Melphalan, cisplatin, carboplatin, doxorubicin, and etoposide cytotoxicities were determined by DIMSCAN assay. Drug resistance progressively increased with therapy and 3/5 post-BMT lines showed high resistance to most drugs. IC 90s 37, 78, 719 and 256 times higher than clinically achievable drug levels were obtained in post-BMT cell lines for melphalan, cisplatin, doxorubicin and etoposide, respectively. Resistance correlated with the therapies patients received: considerable etoposide and doxorubicin resistance (> 1000-fold resistance) was seen in cell lines obtained from patients treated with these drugs. These cell lines indicate that neuroblastoma acquires resistance to cytotoxic drugs that is probably due to stable genetic alterations occurring during therapy.

Antineoplastic Agents↗
PubMed1997

Telomerase expression in primary neuroblastomas.

Maintenance of chromosomal telomeres is necessary for continued cell growth, and this is carried out in germline tissues by telomerase. In contrast to most somatic tissues, many tumours have telomerase activity. The RNA component of human telomerase (hTR) was measured by Northern analyses of 150 primary untreated neuroblastomas and compared with clinical stage at diagnosis. hTR expression > 33 (relative to cell line control = 100) was seen in 41% of all tumours and the frequency of hTR > 33 increased with stage of disease. Expression of hTR may be involved in progression of neuroblastoma.

Blotting, Northern↗
PubMed1997

Gain of chromosome 17 is the most frequent abnormality detected in neuroblastoma by comparative genomic hybridization.

Neuroblastoma behavior is variable and outcome partially depends on genetic factors. However, tumors that lack high-risk factors such as MYCN amplification or 1p deletion may progress, possibly due to other genetic aberrations. Comparative genomic hybridization summarizes DNA copy number abnormalities in a tumor by mapping them to their positions on normal metaphase chromosomes. We analyzed 29 tumors from nearly equal proportions of children with stage I, II, III, IV, and IV-S disease by comparative genomic hybridization. We found two classes of copy number abnormalities: whole chromosome and partial chromosome. Whole chromosome losses were frequent at 11, 14, and X. The most frequent partial chromosome losses were on 1p and 11q. Gains were most frequent on chromosome 17 (72% of cases). The two patterns of gain for this chromosome were whole 17 gain and 17q gain, with 17q21-qter as a minimal common region of gain. Other common gains were on chromosomes 7, 6, and 18. High level amplifications were detected at 2p23-25 (MYCN region), at 4q33-35, and at 6p11-22. Chromosome 17q gains were associated with 1p and/or 11q deletions and advanced stage. The high frequency of chromosome 17 gain and its association with bad prognostic factors suggest an important role for this chromosome in the development of neuroblastoma.

Child, Preschool↗
PubMed1996

Consolidation chemoradiotherapy and autologous bone marrow transplantation versus continued chemotherapy for metastatic neuroblastoma: a report of two concurrent Children's Cancer Group studies.

PURPOSE: To compare event-free survival (EFS) for patients with stage IV neuroblastoma who were treated with induction chemotherapy followed by additional courses of the same chemotherapy or by intensive chemoradiotherapy and autologous bone marrow transplantation (ABMT). METHODS: Two hundred seven children who were diagnosed with stage IV neuroblastoma after 1 year of age were given five to seven courses of induction chemotherapy consisting of cisplatin, etoposide, doxorubicin, and cyclophosphamide (CCC-321-P2). This chemotherapy was continued for 13 total courses for some patients, whereas intensive chemoradiotherapy with ABMT was given to others (CCG-321-P3). The decision to continue chemotherapy versus to consolidate with chemoradiotherapy was not randomized but was made by parents and physicians. Marrow used for ABMT was purged ex vivo and was free of immunocytologically detectable neuroblastoma cells. RESULTS: One hundred fifty-nine of 207 patients (77%) remained event-free during induction therapy. Of these, 67 received chemoradiotherapy/ABMT (CCG-321-P3) and 74 continued chemotherapy (CCG-321-P2). Using Cox regression analysis, the relative risk (RR) of an event after chemoradiotherapy/ABMT was estimated to be 58% of that for patients who continued chemotherapy (P = .01). Similarly, Kaplan-Meier analysis estimated EFS at four years for the chemoradiotherapy/ABMT and chemotherapy groups to be 40% and 19% respectively (P = .019). Subgroups appearing to benefit from chemoradiotherapy/ABMT were those with only a partial tumor response to induction chemotherapy (RR = 0.43; P = .008; EFS, 29% v 6%) and those whose tumors had amplification of the N-myc gene (RR = 0.26; P = .112; EFS, 67% v 0%). CONCLUSION: Consolidation with intensive, myeloablative chemoradiotherapy followed by purged ABMT may be more effective than continuing chemotherapy for patients with stage IV neuroblastoma.

Adolescent↗
PubMed1995

Identification of subsets of neuroblastomas by combined histopathologic and N-myc analysis.

BACKGROUND: Neuroblastomas show different histopathologic phenotypes, and the tumor cells can carry normal or multiple copies of the N-myc proto-oncogene (MYCN). Studies of the N-myc gene and histopathology of untreated primary neuroblastomas have demonstrated that both these factors are important in risk assessment. PURPOSE: Our purpose was to determine if there are any associations between N-myc gene copy number, histopathologic features, clinical stage, and progression-free survival (PFS) and if joint analyses of histopathology and N-myc gene copy number improve risk assessment. METHODS: The histopathologic phenotype and N-myc gene copy number were determined for 232 biopsy/surgery specimens obtained from untreated primary neuroblastoma patients. Tumors were classified as having favorable or unfavorable histology on the basis of Schwannian stroma (rich versus poor), neuroblastic differentiation (differentiating versus undifferentiated), and mitosis-karyorrhexis (fragmenting nucleus) index (MKI; high, intermediate, or low) in the context of age at diagnosis (Shimada classification). N-myc gene amplification was considered significant when the gene copy number was at least 10-fold higher than normal as determined by Southern blot analysis. Otherwise, tumors were classified as nonamplified for N-myc. RESULTS: Among 19 stroma-rich tumors, 11 had grossly visible neuroblastic nodules, and two of these had N-myc amplification. Of 213 stroma-poor tumors, 51 had N-myc amplification, all of which were undifferentiated, and 45 (88% of 51) had high MKI. This histologic phenotype was present in less than 10% of tumors with nonamplified N-myc. Of 162 stroma-poor tumors that showed nonamplified N-myc, 45 (28%) were differentiating and 121 (75%) had low MKI. Neuroblastomas of clinical stages I, II, and IV-S nearly always had favorable histology and no amplification of N-myc. Stage III (regional) and particularly stage IV (metastatic) tumors, however, frequently had unfavorable histologic features with or without N-myc amplification. The estimated PFS at the end of 4 years after diagnosis was 83% for patients whose tumors had favorable histology and no N-myc amplification. The estimated PFS for the patients whose neuroblastomas had unfavorable histology, however, was 29% without and 13% with N-myc amplification, respectively. Subsets of patients with stage II, III, or IV disease were identified by both histologic evaluation and N-myc analysis. Multivariate Cox regression analysis indicated that both the histologic and N-myc-based stratifications provided prognostic information that was independent of staging. CONCLUSIONS: Neuroblastomas with N-myc amplification have a characteristic histopathologic phenotype and an aggressive clinical course. In contrast, neuroblastomas without N-myc amplification exhibit a wide range of histologic features that can define prognostic subsets.

Chi-Square Distribution↗
PubMed1995

Maintenance of normal imprinting of H19 and IGF2 genes in neuroblastoma.

H19 and insulin-like growth factor II (IGF2) are among a few genes which have been confirmed to be imprinted in normal human embryonal tissues. This results in monoallelic expression of maternal H19 and paternal IGF2. Loss of imprinting of these genes producing biallelic expression has been observed in Wilm's tumor and embryonal rhabdomyosarcoma, suggesting that an epigenetic change of DNA, in addition to a genetic change in oncogene(s) and/or tumor suppressor gene(s), may be involved in the development of these childhood cancers. Neuroblastoma, which is an embryonal tumor originating from neural crest-derived cells, occasionally occurs in individuals with the Beckwith-Wiedemann syndrome; Wilm's tumor and embryonal rhabdomyosarcoma occur even more frequently in the Beckwith-Wiedemann syndrome; and paternal uniparental disomy of H19 and IGF2 loci (chromosome 11p15) is present in the Beckwith-Wiedemann syndrome. Furthermore, neuroblastoma cell lines express IGF2, and autocrine/paracrine effects of IGF2 have been demonstrated in these cells. Thus, we examined for imprinting of both H19 and IGF2 in primary untreated neuroblastomas using the RsaI and ApaI polymorphisms within these genes, respectively. Seven of 15 tumors were informative for H19 and for IGF2, and all of these cases showed monoallelic expression of both of these genes. These results indicate that loss of imprinting of H19 and IGF2 does not occur in neuroblastomas.

Base Sequence↗
PubMed1995

Pelvic neuroblastoma--implications for a new favorable subgroup: a Children's Cancer Group experience.

BACKGROUND: The survival in neuroblastoma is influenced by patient age, disease stage, tumor site, and several biologic factors. This study was undertaken to determine if primary pelvic lesions are associated with an unusually favorable outcome. METHODS: Nine hundred eighty-six patients registered on Children's Cancer Group studies from 1980 to 1993 were reviewed, and 41 (4.3%) were found to have pelvic tumors. Survival was analyzed, and correlations among age, stage of disease, surgical resectability, histopathology, serum ferritin, and N-myc oncogene amplification were evaluated. RESULTS: Age at diagnosis was comparable between patients with pelvic and nonpelvic tumors. Disease distribution was similar, with stages III and IV comprising 78% (32 of 41) of pelvic lesions compared with 73% (692 of 945) for nonpelvic tumors. There was no outcome difference in favorable stages (I, II, and IV-S), with 3-year progression-free survival rates of 88% and 82% for pelvic and nonpelvic sites, respectively. However, in stages III and IV, the 3-year progression-free survival was 70% for pelvic lesions compared with 47% for nonpelvic tumors (p = 0.04). Some favorable biologic factors were more common in children with pelvic lesions. CONCLUSIONS: The pelvis is an unusual primary site for neuroblastoma but represents a more favorable prognostic subgroup, which is most evident in advanced-stage disease.

Adolescent↗
PubMed1995

Role of myeloablative therapy in improved outcome for high risk neuroblastoma: review of recent Children's Cancer Group results.

The use of new strategies for dose intensification using peripheral blood stem cell or autologous purged bone marrow rescue has raised expectations for cure in advanced neuroblastoma, although conflicting reports exist regarding the efficacy of these approaches. Using risk groups based on both biological and clinical staging, the Children's Cancer Group (CCG) has conducted a series of pilot studies to test new induction, consolidation and myeloablative regimens to attempt to improve outcome. We summarise below the outcome and prognostic factor analysis for the pilot chemotherapy trial, CCG-(CCG-321P2), and the use of high dose myeloablative chemoradiotherapy with allogeneic (CCG-321P1) or autologous purged bone marrow rescue (CCG-321P3) for high risk neuroblastoma patients who were progression-free at the end of induction chemotherapy. After autologous bone marrow transplantation (ABMT), progression-free survival (PFS) at 4 years was 38% (median follow-up 4 years). Prognostic factors for relapse after ABMT included pre-BMT disease status, bone marrow tumour content at harvest, extent of primary resection at diagnosis, and time to ABMT. MYCN amplification, age, stage, and pre-BMT myeloablative regimen were not significant. Allogeneic BMT did not have a better outcome than ABMT. In a retrospective, non-randomised comparison of ABMT and chemotherapy, there was a significant difference in PFS for stage IV patients. High risk subgroups possibly benefiting from ABMT could be identified, including those with tumour MYCN amplification, over 2 years at diagnosis, and those not in complete remission at the end of induction. A randomised prospective trial comparing myeloablative therapy with ABMT to continuous infusion consolidation chemotherapy is currently underway in CCG to determine the relative benefit.

Adolescent↗
PubMed1995

Phase I trial of 13-cis-retinoic acid in children with neuroblastoma following bone marrow transplantation.

PURPOSE: Treatment of neuroblastoma cell lines with 13-cis-retinoic acid (cis-RA) can cause sustained inhibition of proliferation. Since cis-RA has demonstrated clinical responses in neuroblastoma patients, it may be effective in preventing relapse after cytotoxic therapy. This phase I trial was designed to determine the maximal-tolerated dosage (MTD), toxicities, and pharmacokinetics of cis-RA administered on an intermittent schedule in children with neuroblastoma following bone marrow transplantation (BMT). PATIENTS AND METHODS: Fifty-one assessable patients, 2 to 12 years of age, were treated with oral cis-RA administered in two equally divided doses daily for 2 weeks, followed by a 2-week rest period, for up to 12 courses. The dose was escalated from 100 to 200 mg/m2/d until dose-limiting toxicity (DLT) was observed. A single intrapatient dose escalation was permitted. RESULTS: The MTD of cis-RA was 160 mg/m2/d. Dose-limiting toxicities in six of nine patients at 200 mg/m2/d included hypercalcemia (n = 3), rash (n = 2), and anemia/thrombocytopenia/emesis/rash (n = 1). All toxicities resolved after cis-RA was discontinued. Three complete responses were observed in marrow metastases. Serum levels of 7.4 +/- 3.0 mumol/L (peak) and 4.0 +/- 2.8 mumol/L (trough) at the MTD were maintained during 14 days of therapy. The DLT correlated with serum levels > or = 10 mumol/L. CONCLUSION: The MTD of cis-RA given on this intermittent schedule was 160 mg/m2/d. Serum levels known to be effective against neuroblastoma in vitro were achieved at this dose. The DLT included hypercalcemia, and may be predicted by serum cis-RA levels. Monitoring of serum calcium and cis-RA levels is indicated in future trials.

Bone Marrow Transplantation↗
PubMed1995

Sustained cytokine production and immunophenotypic changes in human neuroblastoma cell lines transduced with a human gamma interferon vector.

The majority of human neuroblastomas express low to undetectable levels of major histocompatibility complex (MHC) class I and II antigens (MHC-I and -II). We studied the effects of gamma interferon (gamma-IFN) transduction on expression of these antigens in six human neuroblastoma cell lines with and without genomic amplification of the N-myc oncogene. All six were stably transduced with an MoMLV-based gamma-IFN retroviral vector (DAh gamma-IFN). G418-resistant cells were assayed for MHC-I, MHC-II, B7-1, and neuroblastoma-associated antigen expression, as well as for gamma-IFN levels in cell culture supernatants. Sustained gamma-IFN production, 2 to > 1000 units/10(6) cells/d, was attained for five of six transduced cell lines and persisted for up to 9 months. This resulted in marked upregulation of MHC-I and MHC-II expression in LA-N-1, LA-N-6, and CHLA-127 cells and moderate upregulation in SK-N-Fi and SK-N-AS cells. One cell line (LA-N-1) had marked induction of MHC-I and MHC-II despite marginal levels of gamma-IFN production. Expression of CD28 ligand B7-1 (as determined by BB1 antibody) remained unchanged in all gamma-IFN-transduced cell lines tested. Expression of several neuroblastoma-associated antigens (NKH1A, 126-4, HSAN 1.2, HNK, 459, and 390) was upregulated in some of the gamma-IFN-transduced cell lines. These results demonstrate that preparation of gamma-IFN expressing neuroblastoma cells for immunotherapeutic purposes is feasible and that gamma-IFN transduction results in phenotypic changes that may improve immunogenicity of human neuroblastoma cells.

B7-1 Antigen↗
PubMed1994

Expression of stem cell factor and c-kit in human neuroblastoma. The Children's Cancer Group.

During development, mice with mutations of stem cell factor (SCF) or its receptor c-kit exhibit defects in melanogenesis, as well as hematopoiesis and gonadogenesis. Because melanocytes derive from neural crest cells, the role of SCF and c-kit was investigated in the neural crest-derived childhood tumor neuroblastoma. Using reverse transcription-polymerase chain reaction analysis, simultaneous expression of steady-state mRNA for the SCF ligand and its receptor c-kit was found in 14 of 14 (100%) human neuroblastoma cell lines and clones and in 8 of 18 (45%) human neuroblastoma tumor samples. Functional blockade of c-kit receptors in the cell lines SK-N-BE(2) and SH-SY5Y using the mouse monoclonal anti-c-kit antibody SR-1 resulted in a significant decrease in cellular growth rate when measured by either 3H-thymidine incorporation or clonogenicity. In addition, higher levels of c-kit mRNA expression were associated with parental neuroblastoma cell lines and subclones with a neuronal (N) differentiation phenotype, whereas lower levels of c-kit mRNA were associated with neuroblastoma cell line subclones having a schwannian/glial/melanocytic pattern of differentiation. However, the differentiation phenotype of neuroblastoma cell lines was not directly altered when c-kit expression was blocked using the SR-1 antibody. In summary, these data indicate that c-kit receptor expression may play a significant role in the growth regulation of the two neuroblastoma cell lines examined and suggest that c-kit may also play a similar role in neuroblastoma growth regulation in vivo. Simultaneous expression of SCF and c-kit mRNA in both neuroblastoma cell lines and tumors implies that c-kit may act as part of an autocrine growth loop in conjunction with endogenous production of SCF in this disease.

Animals↗
PubMed1994

Hsp27 expression in neuroblastoma: correlation with disease stage.

BACKGROUND: The 27-kd heat shock protein (Hsp27) is differentially expressed in some malignancies, including breast carcinoma, leukemia, and malignant fibrous histiocytoma. In breast carcinoma, a high-level expression of Hsp27 has been associated with shorter disease-free survival in patients with localized disease. PURPOSE: We have observed variable levels of Hsp27 among neuroblastoma tumors. Our aim in this study was to investigate the relationship between Hsp27 expression and stage of the disease and N-myc gene copy number. METHODS: We determined Hsp27 protein levels in 53 neuroblastoma tumors representing different stages of the disease and in 17 neuroblastoma cell lines by quantitative two-dimensional polyacrylamide gel electrophoresis (PAGE). We also performed statistical analysis of Hsp27 levels in relation to stage of the disease and to N-myc gene copy number. RESULTS: Increased Hsp27 expression in neuroblastomas was associated with limited stage disease and inversely correlated with N-myc gene amplification, a feature known to predict poor clinical outcome. An inverse correlation was also observed between N-myc gene amplification and Hsp27 protein levels among the neuroblastoma cell lines analyzed. Immunohistochemical staining of sections of neuroblastomas showed that Hsp27 was most prominently expressed in the cytoplasm of large ganglionic tumor cells present in neuronally differentiated areas of the tumors. Induction of neuronal differentiation in SMS-KCNR neuroblastoma cells using retinoic acid resulted in an increase in Hsp27. CONCLUSION: High level expression of Hsp27 in neuroblastoma is a feature of limited stage, differentiated tumors. IMPLICATION: Hsp27 may play a part in the biology of neuroblastomas with a favorable outcome.

Electrophoresis, Polyacrylamide Gel↗