Impact of ovarian transposition before pelvic irradiation on ovarian function among long-term survivors of childhood Hodgkin lymphoma: A report from the St. Jude Lifetime Cohort Study

BACKGROUND

We reviewed the effect of ovarian transposition (OT) on ovarian function among long-term survivors of childhood Hodgkin lymphoma (HL) treated with pelvic radiotherapy.

PROCEDURE

Female participants (age 18+ years) with HL in the St. Jude Lifetime Cohort Study (SJLIFE) were clinically evaluated for premature ovarian insufficiency (POI) 10 or more years after pelvic radiotherapy. Reproductive history including age at menopause and pregnancy/live births was available on all patients.

RESULTS

Of 127 eligible females with HL, 90 (80%) participated in SJLIFE, including 49 who underwent OT before pelvic radiotherapy. Median age at STLIFE evaluation was 38 years (range 25-60). In a multiple regression adjusted for age at diagnosis, pelvic radiotherapy doses > 1,500 cGy (hazard ratio [HR] = 25.2, 95% confidence interval [CI] = 3.1-207.3; P = 0.0027) and cumulative cyclophosphamide equivalent doses of alkylating agents > 12,000 mg/m² (HR = 11.2, 95% CI = 3.4-36.8; P < 0.0001) were significantly associated with POI. There was no significant association between OT and occurrence of POI (HR = 0.6, 95% CI = 0.2-1.9; P = 0.41).

CONCLUSIONS

OT did not appear to modify risk of POI in this historic cohort of long-term survivors of HL treated with gonadotoxic therapy. Modern fertility preservation modalities, such as mature oocyte cryopreservation, should be offered to at-risk patients whenever feasible.

Outcomes of a pediatric surgical oncology fellowship in a pediatric cancer institution

Surgery plays an important role as part of the treatment plan in most children with malignant solid tumors in regards to initial biopsy, upfront resection, and delayed resection. Surgeons also play a critical role in the treatment of surgical complications that may arise during medical treatment. The pediatric surgical oncologist should be familiar with the current treatment guidelines, histology implications, chemotherapy and radiation side effects, tumor staging, and overall care of the child with cancer. Specific training in pediatric surgical oncology is not widespread internationally and it represents a potential undervalued intervention for improving global pediatric cancer care.

Long-term functional outcomes and quality of life in adult survivors of childhood extremity sarcomas: a report from the St. Jude Lifetime Cohort Study

PURPOSE

This study compared measured physical performance, health-related quality of life (HRQOL), and social role attainment between extremity sarcoma survivors and controls, and evaluated associations between disease and treatment exposures, health conditions, and performance measures.

METHODS

Survivors of extremity sarcoma from the St. Jude Lifetime cohort and controls frequency matched by age-, sex-, and race completed physical performance testing and questionnaires. Survivors with Z-scores on outcome measures ≤ -2.0 SD (compared to controls) were categorized with severe impairment/limitation.

RESULTS

Among 206 survivors (52.4 % male median age 36 years (range 19-65)), 37 % had low relative lean mass, 9.7 % had an ejection fraction <50 %, 51.5 % had diffusion capacity for carbon monoxide <75 %, 27.7 % had sensory and 25.2 % motor neuropathy, and 78.2 % had musculoskeletal complications. Severe impairments/limitations were present among ≥25 % of survivors on fitness, balance, and physical HRQOL measures, and among ≥15 % on strength and activity of daily living measures. Lower extremity tumor location (OR 8.23, 95 % CI 2.54-26.67, P value 0.0004) and amputation (OR 8.07, 95 % CI 3.06-21.27, P value <0.0001) were associated with poor fitness. Poor fitness was associated with increased odds of scoring <40 on the SF-36 physical component summary (OR 4.83, 95 % CI 1.95-11.99, P value 0.001) and role-physical subscale (OR 3.34, 95 % CI 1.33-8.43, P value 0.01). Survivors and controls had similar rates of marriage, independent living, employment, and college attendance.

CONCLUSIONS

Extremity sarcoma survivors experience high rates of physical impairment and report lower than expected physical HRQOL. However, they are as likely as peers to be married, live independently, be employed, and attend college.

IMPLICATIONS FOR CANCER SURVIVORS

Follow-up for extremity sarcoma survivors should include assessment of need for further orthopedic care and rehabilitation to address cardiopulmonary and musculoskeletal health.

Long-term outcomes of pediatric and adolescent mediastinal germ cell tumors: a single pediatric oncology institutional experience

PURPOSE

To evaluate the epidemiologic, demographic, and clinical characteristics, as well as prognostic factors and long-term outcomes of mediastinal germ cell tumors (MGCT) in children.

PATIENTS AND METHODS

A retrospective study of pediatric patients diagnosed with a primary MGCT between January 1963 and August of 2014 was performed.

RESULTS

Twenty-five patients were identified. Six children with teratomas were treated with resection alone (median age 7.8 years, range newborn to 15 years) and were cured without recurrence or progression. Nineteen children were treated for a malignant MGCT (median age 11.7 years, range 7 months-18 years); 5 year overall survival (OS) was 0.39 ± 0.12. For malignant non-seminomatous mediastinal germ cell tumors, platinum-based chemotherapy regimen (OS 0.56 vs 0.14, p = 0.03), complete surgical resection with negative margins (OS 0.73 vs 0.11, p = 0.03); and localized disease (OS 0.76 vs 0.0, p = 0.004) demonstrated a survival advantage.

CONCLUSIONS

Initial surgical resection is appropriate for teratomas. Localized disease, complete resection, and platinum-based chemotherapy are associated with improved survival in malignant non-seminomatous mediastinal germ cell tumors. Neoadjuvant, platinum-based three drug regimens followed by delayed surgical resection is the appropriate treatment modality for malignant mediastinal germ cell tumors.

Guidewire Catheter Exchange in Pediatric Oncology: Indications, Postoperative Complications, and Outcomes

BACKGROUND

Maintaining long-term central venous catheters (CVCs) in children undergoing chemotherapy can be challenging. Guidewire catheter exchange (GCE) replaces a CVC without repeat venipuncture. This study evaluated the indications, success rate, and complications of GCE in a large cohort of pediatric cancer patients.

PROCEDURE

Medical records of pediatric cancer patients who underwent GCE at our institution between 2003 and 2013 were retrospectively reviewed. Variables analyzed included gender, age at GCE, primary cancer diagnosis, indication for GCE, absolute neutrophil count (ANC) at GCE, vein used, success rate, and postoperative complications (<30 days after exchange).

RESULTS

A total of 435 GCEs performed in 407 patients (230 males and 177 females) were reviewed. Median age at GCE was 8 years (range, 0.2-24). Acute lymphoblastic leukemia was the most common diagnosis (50.6%). The primary indication for GCE was the desire to have an alternative type of CVC (71%). Other indications included catheter displacement (17%), catheter malfunction (11%), and catheter infection (1%). Median ANC at GCE was 2,581/mm(3) (range, 0-43,400). Left subclavian vein was more commonly used (57.7%). The success rate of GCE was 93.4% (406 of 435 procedures, 95% confidence interval: 91.0-97.5%). A total of 33 (7.5%) postoperative complications occurred including central line associated bloodstream infection (CLABSI) (n = 20, 4.5%), catheter dislodgement (n = 6, 1.4%), and catheter malfunction (n = 7, 1.6%).

CONCLUSIONS

We conclude that GCE in pediatric cancer patients is associated with a high success rate and a low risk of complications. The most common postoperative complication, CLABSI, occurred at a rate significantly lower than following de novo CVC placement.

MicroRNA-204 increases sensitivity of neuroblastoma cells to cisplatin and is associated with a favourable clinical outcome

Background:

Neuroblastoma remains a major cause of cancer-linked mortality in children. miR-204 has been used in microRNA expression signatures predictive of neuroblastoma patient survival. The aim of this study was to explore the independent association of miR-204 with survival in a neuroblastoma cohort, and to investigate the phenotypic effects mediated by miR-204 expression in neuroblastoma.

Methods:

Neuroblastoma cell lines were transiently transfected with miR-204 mimics and assessed for cell viability using MTS assays. Apoptosis levels in cell lines were evaluated by FACS analysis of Annexin V-/propidium iodide-stained cells transfected with miR-204 mimics and treated with chemotherapy drug or vehicle control. Potential targets of miR-204 were validated using luciferase reporter assays.

Results:

miR-204 expression in primary neuroblastoma tumours was predictive of patient event-free and overall survival, independent of established known risk factors. Ectopic miR-204 expression significantly increased sensitivity to cisplatin and etoposide in vitro. miR-204 direct targeting of the 3′ UTR of BCL2 and NTRK2 (TrkB) was confirmed.

Conclusion:

miR-204 is a novel predictor of outcome in neuroblastoma, functioning, at least in part, through increasing sensitivity to cisplatin by direct targeting and downregulation of anti-apoptotic BCL2. miR-204 also targets full-length NTRK2, a potent oncogene involved with chemotherapy drug resistance in neuroblastoma.

Successful attenuation of humoral immunity to viral capsid and transgenic protein following AAV-mediated gene transfer with a non-depleting CD4 antibody and cyclosporine

The ability of transient immunosuppression with a combination of a non-depleting anti-CD4 (NDCD4) antibody and cyclosporine (CyA) to abrogate immune reactivity to both adeno-associated viral vector (AAV) and its transgene product was evaluated. This combination of immunosuppressants resulted in a 20-fold reduction in the resulting anti-AAV8 antibody titres, to levels in naïve mice, following intravenous administration of 2 × 10(12) AAV8 vector particles per kg to immunocompetent mice. This allowed efficient transduction upon secondary challenge with vector pseudotyped with the same capsid. Persistent tolerance did not result, however, as an anti-AAV8 antibody response was elicited upon rechallenge with AAV8 without immunosuppression. The route of vector administration, vector dose, AAV serotype or the concomitant administration of adenoviral vector appeared to have little impact on the ability of the NDCD4 antibody and CyA combination to moderate the primary humoral response to AAV capsid proteins. The combination of NDCD4 and CyA also abrogated the humoral response to the transgene product, that otherwise invariably would occur, following intramuscular injection of AAV5, leading to stable transgene expression. These observations could significantly improve the prospects of using rAAV vectors for chronic disorders by allowing for repeated vector administration and avoiding the development of antibodies to the transgene product.

Maturation of tumor vasculature by interferon-beta disrupts the vascular niche of glioma stem cells

BACKGROUND

The vascular niche necessary for cancer stem cell maintenance is a potential target for cancer therapy.

MATERIALS AND METHODS

Human glioma xenografts were treated with IFN-β delivered systemically via a liver-targeted, adeno-associated viral vector. The vascular niche was examined with immunofluorescence for glioma stem cells, endothelial cells, and perivascular cells.

RESULTS

Although IFN-β was not directly toxic to glioma stem cells in vitro, IFN-β decreased tumor size and the number of stem cells recovered in both heterotopic and orthotopic models. Treatment with IFN-β increased perivascular cells investing the tumor vasculature (6-fold) distancing stem cells from endothelial cells. Additionally, vascular smooth muscle cells co-cultured between stem cells and endothelial cells decreased stem cell recovery.

CONCLUSION

Continuous delivery of IFN-β decreased the number of stem cells in glioma xenografts by disrupting the vascular niche through an increase in perivascular cells, which created a barrier between the glioma stem cells and the endothelial cells.

NF-kappaB activation mediates resistance to IFN beta in MLL-rearranged acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) harboring the t(4;11) translocation is associated with a very poor prognosis; innovative treatment strategies are required to improve the current 5-year survival rate of 30-40%. Interferon beta (IFN beta) has shown promise in the treatment of both solid and hematologic malignancies, although the short half-life and toxicity associated with high doses have limited its clinical utility. To overcome these limitations, we investigated the effect of continuous, gene transfer-mediated delivery of IFN beta using adeno-associated virus (AAV)-mediated expression, on ALL cells with the t(4;11) translocation. We found that this method of IFN beta delivery resulted in complete remission of leukemia in a murine model. However, leukemic cells eventually became resistant to IFN beta and relapse was observed. Activation of NF-kappaB was identified as a mechanism for IFN beta resistance, and inhibition of NF-kappaB activity in resistant cells sensitized cells to IFN beta. IFN beta combined with agents that inhibit NF-kappaB could have therapeutic potential in the treatment of children with mixed lineage leukemia subtype ALL.

Enhancing transduction of the liver by adeno-associated viral vectors

A number of distinct factors acting at different stages of the adeno-associated virus vector (AAV)-mediated gene transfer process were found to influence murine hepatocyte transduction. Foremost among these was the viral capsid protein. Self-complementary (sc) AAV pseudotyped with capsid from serotype 8 or rh.10 mediated fourfold greater hepatocyte transduction for a given vector dose when compared with vector packaged with AAV7 capsid. An almost linear relationship between vector dose and transgene expression was noted for all serotypes with vector doses as low as 1 x 10(7) vg per mouse (4 x 10(8) vg kg(-1)) mediating therapeutic levels of human FIX (hFIX) expression. Gender significantly influenced scAAV-mediated transgene expression, with twofold higher levels of expression observed in male compared with female mice. Pretreatment of mice with the proteasome inhibitor bortezomib increased scAAV-mediated hFIX expression from 4+/-0.6 to 9+/-2 microg ml(-1) in female mice, although the effect of this agent was less profound in males. Exposure of mice to adenovirus 10-20 weeks after gene transfer with AAV vectors augmented AAV transgene expression twofold by increasing the level of proviral mRNA. Hence, optimization of individual steps in the AAV gene transfer process can further enhance the potency of AAV-mediated transgene expression, thus increasing the probability of successful gene therapy.

AAV-mediated delivery of interferon-β for the treatment of retinoblastoma in preclinical models

3565

Background: Interferon-β has anti-tumor properties against a variety of malignancies through direct cytotoxicity as well as immunological effects. In order to circumvent limitations of IFN-β therapy, we have developed an adeno-associated viral gene therapy approach to deliver IFN-β directly to tumors. In this study, we tested the efficacy of AAV mediated delivery of IFN-β in preclinical retinoblastoma models. Retinoblastoma is an ideal candidate for gene-therapy based anti-cancer treatments because viral infection and IFN-β delivery can be contained within the ocular environment thereby minimizing systemic toxicity. Methods: Retinoblastoma cell lines Weri and Y79 were treated in vitro with recombinant human Interferon-β and then subjected to Viacount assays, Nexin apoptosis assays, FACS cell cycle analysis, and immunolabeling for proliferation (BrdU) and apoptosis (caspase and TUNEL). An orthotopic Xenograft retinoblastoma rat model with luciferase reporter were established and treated with single subconjunctival injection of AAV-IFN-β gene therapy. Xenogen in vivo imaging was used to follow tumor volume. Blood and tissue samples (ELISA) were obtained to determine IFN-β levels. Results: Weri and Y79 cells showed maximum reduction in viability at 500 IU/ml and 2500 IU/ml respectively. Weri response was found to be cell death by Caspase and TUNEL assay. Y79 response was found to be due to suppression of proliferation as measured by BrdU incorporation and cell cycle analysis. In the retinoblastoma xenograft model there was no increase in tumor volume by serial in vivo imaging compared to control animals. Stable levels of IFN-β were maintained at 20 ng/ml >6weeks following injection. Plasma levels were undetectable 42 days following treatment. Conclusions: Retinoblastoma cell lines exhibit pleiotropic responses to IFN-β consistent with previous studies. Intravitreal injection of AAV-IFN-β resulted in efficient retinal infection and sustained IFN-β production. Viral spread outside of the eye was not detected. Using our retinoblastoma xenograft model we found that intravitreal injection of AAV-IFN-β had a potent anti-tumor effect in vivo. These data suggest that AAV mediated delivery of IFN-β may provide a complementary approach to systemic chemotherapy.

No significant financial relationships to disclose.

Antitumor efficacy of AAV-mediated systemic delivery of interferon-beta

Type I interferons (alpha/beta) have significant antitumor activity although their short half-life and systemic side effects have limited their clinical utility. An alternative dosing schedule of continuous, low-level delivery, as is achieved by gene therapy, rather than intermittent, high concentration pulsed-dosing, might avoid the toxicity of interferon while maintaining its antitumor efficacy. We have tested a gene therapy approach in murine tumor models to treat malignancies that have shown responsiveness to interferon in clinical trials. The tumor cell lines used were moderately sensitive to the direct effects of human interferon-beta (hIFN-beta) in vitro. For in vivo testing, systemic delivery of hIFN-beta was generated following liver-targeted delivery of adeno-associated virus (AAV) vector carrying the hIFN-beta transgene. This prevented engraftment of subcutaneous human gliomas, and orthotopic, localized (intrarenal) and disseminated (primarily pulmonary) human renal cell carcinomas; and caused regression of established tumors at these sites. In a syngeneic, immunocompetent model of melanoma, AAV IFN-beta treatment limited subcutaneous tumor growth and prevented disseminated disease. A significant decrease in mean intratumoral vessel density was demonstrated in hIFN-beta-treated tumors, suggesting that in addition to a direct tumoricidal effect, the antitumor efficacy of AAV IFN-beta in this study was due to its ability to inhibit angiogenesis.

Current status and prospects for gene therapy

Gene therapy is a new and exciting therapeutic concept that offers the promise of cure for an array of inherited, malignant and infectious disorders. After years of failure, substantial progress in the efficiency of gene-transfer technology has recently resulted in impressive clinical success in infants with immunodeficiency. Two of these children have, however, subsequently developed leukaemia as a result of insertional mutagenesis, raising concerns about the safety of genetic therapeutics. The purpose of this article is to review the current status of gene therapy in light of recent successes and tragedies, and to consider the challenges faced by this relatively new field.

Prospects for gene therapy of haemophilia

That gene therapy offers the promise of a cure for haemophilia was apparent more than a decade ago. After years of failure, substantial progress in the efficiency of gene transfer technology has recently resulted in impressive success in animal models with haemophilia. However, fears of the risks intrinsic to such therapy have been raised by the fate of two children cured of immune deficiency by gene transfer who have, however, subsequently developed leukaemia as a result of insertional mutagenesis. The purpose of this review is to outline the current status of gene therapy in light of recent successes and tragedies and to consider the prospects for curing haemophilia in the short-to-medium term.

Is reexcision in pediatric nonrhabdomyosarcoma soft tissue sarcoma necessary after an initial unplanned resection?

PURPOSE

The aim of this study was to determine the importance of pretreatment reexcision (PRE) of pediatric nonrhabdomyosarcoma soft tissue sarcoma (NRSTS) after initial unplanned resection.

METHODS

The authors retrospectively reviewed the records of 116 consecutive patients with surgically resected NRSTS treated at their institution between February 1978 and September 1999. Ninety-four (81.0%) patients had undergone unplanned resections before referral to their institution for further therapy. Demographic data, tumor characteristics, treatment administered, and outcomes were recorded.

RESULTS

Sixty-nine patients (73.4%) underwent PRE at a median interval after the initial unplanned resection of 29 days. Twenty-five patients were thought unsuitable for PRE because of the proximity to vital neurovascular bundles. Tumors deemed not feasible for PRE were more likely to be greater than 5 cm (P =.0094) and high grade (P =.0200). Tumor was found in 33 (47.8%) of the PRE specimens, and 24 of these patients (72.7%) were deemed disease free after achieving negative surgical margins. Residual tumor was more likely to be found after PRE in head and neck primary tumors than in trunk wall or extremity primary tumors (P =.0128). There were no local failures in the 60 PRE patients who achieved clear margins. The estimated 5-year event-free and 5-year overall survival rates in these 60 patients were 98.3% +/- 2.0% and 98.2% +/- 2.1%, respectively.

CONCLUSIONS

Pretreatment reexcision should be performed whenever feasible in pediatric patients with NRSTS who had an initial unplanned resection. The proportion of patients with residual tumor in the PRE specimen is high, and negative microscopic margins can be achieved after PRE in most patients with residual tumor. Despite delay in obtaining a complete surgical resection, no local recurrences were seen. The possibility of NRSTS should be considered when resecting a soft tissue mass in children, and diagnostic incisional biopsy followed by wide local excision with negative microscopic margins should be the surgical goal.

The inhibitor of apoptosis protein survivin is associated with high-risk behavior of neuroblastoma

BACKGROUND/PURPOSE

Apoptotic factors inducing or preventing cell death may intrinsically govern the behavior of some tumors. Survivin is a recently described member of the inhibitor of apoptosis protein (IAP) family, that is expressed in a cell cycle-dependent manner and is found in tumors of unfavorable histology. This study examines the presence of several apoptotic factors, including survivin, in neuroblastoma (NB) tumors. Clues to survivin's function in NB are provided by examining its association with behavior and cell dynamics in tumors and cell lines.

METHODS

Expression of a panel of apoptosis factors were quantified in 15 NB and related tumors before chemotherapy and in 3 NB cell lines (NB7, NB10, and NB16). Survivin and other apoptotic factors, as well N-myc amplification in primary tumors was correlated with recurrent disease and outcome. Proliferation rate, apoptosis assays, cell cycle analysis, and drug- or immune-mediated cell death were assessed in cell lines and evaluated in the context of differential survivin and apoptosis gene expression.

RESULTS

All 7 tumors that went on to recur expressed survivin, whereas expression was absent in all 8 tumors that went into remission. N-myc was amplified in 4 (57.1%) of the 7 recurrent tumors. Of the 8 tumors that were cured, Fas was expressed in 3 (38%), TRAIL-R1 in 6 (75%) and tumor necrosis factor (TNF)-R1 in 8 (100%), whereas these pro-apoptotic receptors were present in only 1 (14%), 1 (14%), and 4 (57%) of the 7 tumors that went on to recur, respectively. Of the 3 cell lines, NB10 expressed the least survivin, displayed the lowest proliferation index, and had the fewest number of cells in the G2/M (mitotic) phase of the cell cycle. Furthermore, NB10 also was most sensitive to TNF-related apoptosis-inducing ligand (TRAIL) or etoposide-induced cell death.

CONCLUSIONS

In primary NB tumors, survivin expression was associated with tumors of high risk and unfavorable prognosis, whereas pro-apoptotic receptor expression was more abundant in tumors of favorable prognosis. In this small series, survivin expression appeared to be more predictive of recurrent disease than N-myc amplification. In cell lines, survivin expression was cell cycle dependent, and its expression was associated with greater proliferation rates and greater resistance to drug- or immune-mediated cell death. Survivin expression may become a useful prognostic marker in NB and could be a potential target for the treatment of this tumor. J Pediatr Surg 36:1785-1791.

Bone marrow-derived cells contribute to tumor neovasculature and, when modified to express an angiogenesis inhibitor, can restrict tumor growth in mice

Inhibition of tumor-induced neovascularization appears to be an effective anticancer approach, although long-term angiogenesis inhibition may be required. An alternative to chronic drug administration is a gene therapy-mediated approach in which long-term in vivo protein expression is established. We have tested this approach by modifying murine bone marrow-derived cells with a gene encoding an angiogenesis inhibitor: a soluble, truncated form of the vascular endothelial growth factor receptor-2, fetal liver kinase-1 (Flk-1). Murine bone marrow cells were transduced with a retroviral vector encoding either truncated, soluble Flk-1 (tsFlk-1) together with green fluorescent protein (GFP) or GFP alone. Tumor growth in mice challenged 3 months after transplantation with tsFlk-1-expressing bone marrow cells was significantly inhibited when compared with tumor growth in control-transplanted mice. Immunohistochemical analysis of tumors in each group demonstrated colocalization of GFP expression in cells staining with endothelial cell markers, suggesting that the endothelial cells of the tumor-induced neovasculature were derived, at least in part, from bone marrow precursors. These results suggest that long-term expression of a functional angiogenesis inhibitor can be generated through gene-modified, bone marrow-derived stem cells, and that this approach can have significant anticancer efficacy. Modifying these cells seems to have the added potential benefit of targeting transgene expression to the tumor neovasculature, because bone marrow-derived endothelial cell precursors seem to be recruited in the process of tumor-induced angiogenesis.

Molecular genetic aspects of solid tumors in childhood

Advances in molecular genetic research in the past 2 decades have led to an increased understanding of the genetic events in the pathogenesis and progression of human malignancies, including those of childhood. A number of pediatric malignancies have served as models for the molecular genetic approach to patients with cancer. These have highlighted the utility of molecular analysis for a variety of purposes including diagnosis, risk stratification and treatment planning, understanding of syndromes associated with cancer and genetic screening, genetic counseling and prophylactic treatment including surgery. It is likely that there soon will be individualized treatment regimens based on the molecular biologic profile of a patient's tumor. In addition, molecular profiling will lead to new drug development designed to induce differentiation of tumor cells, block dysregulated growth pathways, or reactivate silenced apoptotic pathways. This review discusses the molecular genetic aspects of some of the more common pediatric tumors as well as tumors whose pathogenetic mechanisms are particularly instructive.

Autocrine expression of both endostatin and green fluorescent protein provides a synergistic antitumor effect in a murine neuroblastoma model

Modalities that act through different mechanisms can often provide synergistic antitumor activity for the treatment of refractory tumors when used in combination. Here we report a gene therapy approach in which the genes for the angiogenesis inhibitor, endostatin, and the marker protein and potent immunogen, green fluorescent protein (GFP), were delivered to murine neuroblastoma cells prior to inoculation of the tumor cells into syngeneic immunocompetent mice. Although the effect of either angiogenesis inhibition or immunomodulation alone resulted in only a modest delay in tumor growth, when these approaches were used in combination, prevention of the formation of appreciable tumors was effected in 15 of 24 (63%) mice. The combination of endostatin and GFP expression elicited a strong immune response that was T cell-mediated and was reactive against both GFP and tumor cell line-specific antigens. This afforded treated mice protection against subsequent tumor challenge with unmodified tumor cells. These results suggest that antiangiogenic and immunotherapy strategies, when used in a gene therapy-mediated approach, can act synergistically in an effective multimodality anticancer approach.

Factors influencing in vivo transduction by recombinant adeno-associated viral vectors expressing the human factor IX cDNA

Long-term expression of coagulation factor IX (FIX) has been observed in murine and canine models following administration of recombinant adeno-associated viral (rAAV) vectors into either the portal vein or muscle. These studies were designed to evaluate factors that influence rAAV-mediated FIX expression. Stable and persistent human FIX (hFIX) expression (> 22 weeks) was observed from 4 vectors after injection into the portal circulation of immunodeficient mice. The level of expression was dependent on promoter with the highest expression, 10% of physiologic levels, observed with a vector containing the cytomegalovirus (CMV) enhancer/beta-actin promoter complex (CAGG). The kinetics of expression after injection of vector particles into muscle, tail vein, or portal vein were similar with hFIX detectable at 2 weeks and reaching a plateau by 8 weeks. For a given dose, intraportal administration of rAAV CAGG-FIX resulted in a 1.5-fold or 4-fold higher level of hFIX compared to tail vein or intramuscular injections, respectively. Polymerase chain reaction analysis demonstrated predominant localization of the rAAV FIX genome in liver and spleen after tail vein injection with a higher proportion in liver after portal vein injection. Therapeutic levels of hFIX were detected in the majority of immunocompetent mice (21 of 22) following intravenous administration of rAAV vector without the development of anti-hFIX antibodies, but hFIX was not detected in 14 immunocompetent mice following intramuscular administration, irrespective of strain. Instead, neutralizing anti-hFIX antibodies were detected in all the mice. These observations may have important implications for hemophilia B gene therapy with rAAV vectors.

Accuracy of percutaneous lung biopsy for invasive pulmonary aspergillosis

BACKGROUND

Invasive pulmonary aspergillosis is fulminant and often fatal in immunosuppressed patients. Percutaneous biopsy may select patients who could benefit from surgical resection.

OBJECTIVE

We sought to determine the accuracy of percutaneous biopsy for pediatric invasive pulmonary aspergillosis.

MATERIALS AND METHODS

We retrospectively reviewed 28 imaging-guided percutaneous biopsies of the lungs of 24 children with suspected pulmonary aspergillosis. Twenty-two were being treated for malignancy and two for congenital immunodeficiency; 15 had received bone-marrow transplants. The accuracy of the percutaneous lung biopsy was determined by subsequent surgical resection, autopsy, or clinical course.

RESULTS

Histopathological studies showed ten biopsy specimens with septate hyphae, indicating a mold, and seven with Aspergillus flavus colonies in culture. The remaining 18 biopsies revealed no fungi. No patient had progressive aspergillosis after negative biopsy. Invasive pulmonary mold was detected by percutaneous biopsy with 100% (10/10) sensitivity and 100% (18/18) specificity. Percutaneous biopsy results influenced the surgical decision in 86% (24 of 28) of the cases. Bleeding complicated the biopsy in 46% (13/28) and hastened one death.

CONCLUSION

Percutaneous biopsy of the lung is an accurate technique for the diagnosis of invasive pulmonary aspergillosis and correctly determines which immunosuppressed pediatric patients would benefit from therapeutic pulmonary resection.

The association of elevated percent bands on admission with failure and complications of interval appendectomy

BACKGROUND/PURPOSE

The routine use of interval appendectomy for the treatment of perforated appendicitis, with or without abscess, remains controversial. The purpose of this study is to confirm the efficacy of this approach and to identify factors associated with failures and complications.

METHODS

All patients (n = 101) with their clinical diagnosis of perforated appendicitis confirmed with imaging were treated prospectively with fluids and intravenous antibiotics (clindamycin, ceftazidime) and were discharged home on oral fluids and analgesics regardless of fever. Intravenous antibiotics were continued at home until the patients were afebrile for 48 hours, and their white blood cell and differential counts were normal. Patients were readmitted at 8 to 12 weeks for an interval appendectomy. Failure to improve by 72 hours of antibiotic therapy mandated an early appendectomy. P values were determined by chi(2) analysis and Student's t test.

RESULTS

The 79 patients (78%) successfully treated with interval appendectomy had an overall 6.3% complication rate, and total hospitalization averaged 5.2 days. The treatment in 21 of 22 patients (22%) requiring early appendectomy failed because of a clinical picture suggesting small bowel obstruction. The patients with the failed procedures had a complication rate of 50% and were hospitalized an average of 12.8 days. The overall complication rate for the 101 patients was 15.8%, and the overall total hospitalization was 6.9 days. Patients requiring early appendectomy had a more frequent finding resembling a small bowel obstruction on their initial x-ray (50% v 13%, P = .004) and a higher percent band count on their initial differential blood cell count (22.6% v 7.6%, P<0.0001) than did those successfully treated with interval appendectomy. An initial band count <15% was predictive of an uncomplicated course (84% positive predictive value).

CONCLUSIONS

Interval appendectomy without complications is successful in the majority of patients with perforated appendicitis. An elevated initial band count > or =15% is associated with an increased likelihood of failure and complications.

Gene therapy-mediated expression by tumor cells of the angiogenesis inhibitor flk-1 results in inhibition of neuroblastoma growth in vivo

BACKGROUND/PURPOSE

Preventing tumors from forming new blood vessels appears to be an effective new anticancer approach. Antiangiogenic therapy usually is cytostatic, however, and, therefore, long-term angiogenesis inhibition is likely to be required. The objective of this study was to determine if sustained gene therapy-mediated expression of these agents from tumor cells could restrict tumor growth in vivo.

METHODS

Two replication-defective retroviral vectors were made, one encoding both the soluble, truncated vascular endothelial growth factor receptor (VEGF-R2), flk-1, together with green fluorescent protein (GFP), and the other encoding GFP alone. These vectors were then used to transduce murine neuroblastoma cells (NXS2). Stable, high expression of the flk-1 transgene was confirmed in the former population of cells by Western analysis. Flk-1 protein was isolated from cell culture supernatants and tested in human umbilical vein endothelial cell (HUVEC) proliferation and migration assays to confirm that functional protein was being made. Finally, in vivo activity was assessed by injecting 10(6) tumor cells subcutaneously into SCID mice and monitoring subsequent tumor growth.

RESULTS

Purified flk-1 (0.1 micromol/L) was able to inhibit basic fibroblast growth factor (bFGF) stimulated HUVEC proliferation by 44% and VEGF-stimulated migration by 30%. In vitro growth rates for the transduced cell lines were similar to the unmodified cell line. In vivo, however, after 23 days, tumors from flk-1 expressing neuroblastoma cells were less than 33% the average volume of tumors from cells expressing only the GFP transgene (mean volume, 1.9 cm(3) v 5.8 cm(3), P<.001). GFP expression alone had no effect on tumor growth when compared with unmodified tumor cells.

CONCLUSIONS

Engineered expression of flk-1, a competitive inhibitor of VEGF, by tumor cells results in the production of an inhibitor of endothelial cell proliferation and migration that greatly restricts the growth of the tumor cells in vivo. Gene therapy-mediated delivery of angiogenesis inhibitors may provide an alternative approach to treating refractory tumors such as neuroblastoma.

Humoral response to vaccination with interleukin-2-expressing allogeneic neuroblastoma cells after primary therapy

BACKGROUND

Immunotherapy using cytokine-expressing tumor cells has shown promise as an anticancer strategy. We have recently begun a trial of interleukin-2 (IL-2) gene-modified allogeneic neuroblastoma cells administered in a sequence of eight injections to patients with high-risk neuroblastoma following completion of primary therapy. Six patients to date have completed treatment.

PROCEDURE

We examined humoral responses to the immunizing cell line and, when available, to the patients' autologous tumor cells using an in vitro binding assay.

RESULTS

Five of six patients developed a rise in antitumor antibodies to the immunizing neuroblastoma cell line following vaccination. Two of these patients had autologous tumor available; both demonstrated a humoral response to these cells as well.

CONCLUSIONS

Our results demonstrate that vaccination with IL-2-expressing allogeneic tumor cells after intensive primary therapy can elicit a humoral response to the immunizing line. These antibodies are cross-reactive with the patients' own tumor cells in the two cases in which autologous cells were available. This suggests that different patients' tumors may share common antigens that can be exploited in immunotherapy strategies and supports the continued exploration of allogeneic tumor cells as tumor vaccines.

Retroviral vector-producer cell mediated angiogenesis inhibition restricts neuroblastoma growth in vivo

BACKGROUND

The purpose of this study was to determine whether gene therapy-mediated delivery of an angiogenesis inhibitor, a truncated, soluble vascular endothelial growth factor receptor (Flk-1/KDR, VEGFR-2), could suppress tumor growth in a murine model of neuroblastoma.

METHODS

Murine fibroblasts producing a replication-defective retrovirus encoding this mutant form of flk-1 were made. These producer cells were mixed with neuroblastoma cells and injected subcutaneously into SCID mice. Subsequent tumor growth was then measured.

RESULTS

Murine neuroblastoma growth was decreased by 95% after 25 days. Similar tumor growth inhibitory effects were observed when the flk-1 producer cells were co-injected with cells from two different human neuroblastoma cell lines.

CONCLUSIONS

Neuroblastoma growth can be significantly restricted in vivo with a single injection of cells that produce a retroviral vector encoding the gene for an angiogenesis inhibitor. This suggests that gene therapy-mediated delivery can be an effective alternative to chronic administration of these cytostatic anticancer agents.

Hepatic iron concentration: noninvasive estimation by means of MR imaging techniques

PURPOSE

To identify a magnetic resonance (MR) imaging method sufficiently sensitive and specific in the estimation of hepatic iron content to obviate liver biopsy.

MATERIALS AND METHODS

Thirty-eight patients underwent percutaneous needle biopsy of the liver with chemical measurement of the hepatic iron concentration and hepatic MR imaging with several spin-echo and gradient-recalled-echo (GRE) techniques. Correlations between MR imaging parameters and the hepatic iron concentration were determined.

RESULTS

Inverse curvilinear relationships were noted between several MR parameters and hepatic iron concentrations. GRE sequences with short repetition and echo times were more accurate and precise than spin-echo sequences for the estimation of hepatic iron concentration. A GRE sequence with a repetition time of 18 msec, an echo time of 5 msec, and a flip angle of 10 degrees showed close correlation between the hepatic iron concentration and the natural logarithm of the ratio of the signal intensity of liver to the SD of background noise (r = -0.94) and low coefficient of variation (12%).

CONCLUSION

MR imaging with these parameters is a rapid, noninvasive, and accurate modality for estimation of hepatic iron concentration; it is sufficiently accurate and precise to obviate liver biopsy for the purpose of measuring hepatic iron concentration.

Enhanced neuroblastoma transduction for an improved antitumor vaccine

BACKGROUND

A recent clinical trial of an antineuroblastoma vaccine used adenovirus serotype 5 (Ad5) vectors to transduce autologous tumor cells with the gene encoding IL-2. A method to improve transduction efficiency was sought to enable the use of lower viral titers, especially when in situ adenoviral-mediated tumor cell transduction is considered.

MATERIALS AND METHODS

A chimeric adenoviral delivery vector was utilized in which the fiber head from adenovirus serotype 3 was incorporated into the backbone of Ad5. Since the fiber head protein is responsible for viral attachment to target cells, a different spectrum and range of infectivity might result. Both the chimeric (Av9LacZ4) and Ad5 (Av1LacZ4) vectors were constructed to carry a beta-galactosidase transgene. The relative transduction efficiency of these two vectors was then evaluated in five tumor-derived short-term neuroblastoma cultures and four established neuroblastoma cell lines. Enzyme activity was assessed using three different methods: in situ staining, flow cytometric analysis, and a quantitative assay.

RESULTS

A significant improvement in transduction efficiency of the short-term neuroblastoma cultures with the new chimeric adenovector was demonstrated. A similar improvement in transduction efficiency was not observed in the established cell lines, suggesting that the cell surface receptor for the Ad 3 serotype had been lost in vitro. Increased transduction of tumor cells with N-myc amplification was also observed.

CONCLUSIONS

The newly constructed chimeric adenoviral vector transduces short-term neuroblastoma cultures more efficiently than the standard Ad5 vector. This vector will permit the use of lower viral titers and may be useful in other adenoviral-based gene-therapy protocols. Increased transgene expression in N-myc-amplified cells offers possible selectivity for in situ gene delivery.

Neuroblastoma regression and immunity induced by transgenic expression of interleukin-12

PURPOSE

Interleukin-12 (IL-12) is a cytokine with potent antitumor effects. The authors sought to assess its capacity to increase tumor immunogenicity when expressed by tumor cells in a murine model of neuroblastoma.

METHODS

Syngeneic A/J mice were inoculated subcutaneously with 2 x 10(6) cells from a murine neuroblastoma-derived cell line (neuro-2a). In situ transduction of the neuroblastoma cells was achieved by intratumoral injection of an adenoviral vector encoding both subunits of the murine IL-12 heterodimer. Growth of the IL-12 gene-modified tumor cells was compared with untreated neuro-2a cells. Tumor immunity was assessed by rechallenging mice that had rejected their tumor with unmodified neuroblastoma cells. The contribution of cytotoxic T lymphocytes (CTLs) was evaluated through cytotoxicity assays.

RESULTS

Eighteen (72%) of 25 tumor-bearing mice treated with the mlL-12 adenoviral vector exhibited tumor regression, with 12 mice (48%) completely rejecting their tumors over 2 to 3 weeks. None of the mice that had rejected their tumor and were rechallenged with unmodified neuro-2a cells subsequently developed new tumors. Pooled splenocytes from mice rejecting their tumors showed significant tumor killing (>20% cytolysis) in vitro in 51Cr release assays.

CONCLUSIONS

Adenoviral-mediated IL-12 expression by tumor cells in a murine neuroblastoma model produced a significant antitumor response. Most treated tumors demonstrated at least transient regression, whereas many completely regressed. Cured mice exhibited protective immunity and CTL activity against the tumor. These data confirm the immunomodulatory efficacy of IL-12 as part of a vaccine-based antineuroblastoma strategy.

Control of monocyte influx in glomerulonephritis in transplanted kidneys in the rat

Induction of anti-Thy-1 nephritis in different strains of inbred rats results in phenotypically different types of renal diseases. In Wistar and Lewis (LEW) rats, a transient influx of ED1+ macrophages occurs 24 hours after injection of anti-Thy-1 antibodies, whereas this does not occur in F344 rats. The present experiments were designed to investigate the role of the kidney in the regulation of the monocyte influx in this model. To dissociate the role of the immune system from local intrarenal factors in the control of monocyte influx, anti-Thy-1 nephritis was induced in LEW rats with an F344 kidney transplant and in F344 rats with a LEW kidney allograft. Acute rejection episodes were prevented by treatment with an anti-CD4 monoclonal antibody. Control rats received a syngeneic kidney graft. Monocyte influx after injection of anti-Thy-1 antibodies was found in the glomeruli of both LEW and F344 kidneys removed from LEW recipients, whereas there was no demonstrable monocyte influx after infusion of anti-Thy-1 antibodies in either LEW or F344 kidneys removed from F344 recipients. Monocyte infiltration correlated with the subsequent expansion of the mesangial extracellular matrix. The inability to attract monocytes was not due to the lack of glomerular expression of chemokines, because F344 and LEW glomeruli demonstrated a similar expression of monocyte chemoattractant protein-1 (MCP-1). Differences in the ability to activate the complement system were excluded. We conclude that the immune system controls the glomerular influx of monocytes and that the reaction of the mesangial cells is probably controlled by combinations of cytokines produced during the inflammatory process.

Wilms tumor presenting with abdominal pain: a special subgroup of patients

BACKGROUND

Although significant progress has been made in the management of children with Wilms tumor, two major controversies still exist: the extent of radiographic evaluation necessary before surgery and the role of preoperative chemotherapy. This study sought to determine whether patients with Wilms tumor who presented with abdominal pain defined a special subset of patients who might require a more extensive preoperative work-up and neoadjuvant chemotherapy.

METHODS

From 1970 to 1995, 250 children were treated for Wilms tumor at a single pediatric institution. A retrospective chart review determined presenting signs and symptoms for each patient.

RESULTS

Thirty-four (14%) patients (mean age 5.5 years) sought medical attention with a chief complaint of abdominal pain. The stage distribution for these patients tended to be higher and was significantly different (P <.001, chi(2)-analysis) from those presenting without pain. Four (14%) of 29 patients with tumor available for analysis were found to have anaplastic histology.

CONCLUSION

These data suggest that patients with Wilms tumor who present with abdominal pain represent a special subgroup that tends to be older and has an increased incidence of tumor rupture, anaplasia, and higher stage. These patients may benefit from a more extensive preoperative evaluation and consideration of neoadjuvant chemotherapy.

Wandering spleen: a challenging diagnosis

Wandering spleen is rare, particularly in children, and diagnosis is difficult. It usually occurs at 20 to 40 years of age, and most cases are seen in women. Diagnosis is difficult because of lack of symptoms, unless splenic torsion has occurred. Patients usually have an asymptomatic abdominal mass, an acute abdomen, or, most commonly, a mass associated with pain. Laboratory data are nonspecific, but the diagnosis can be confirmed by imaging studies; computed tomography and duplex ultrasonography are preferred modalities. Treatment is operative because of complications of splenic infarction and possible splenectomy. Splenopexy is the treatment of choice for a noninfarcted wandering spleen. Splenectomy should be done only when there is no evidence of splenic blood flow after detorsion of the spleen. We review our experience with wandering spleen in two pediatric patients, one treated with splenopexy and the other with splenectomy.

Neonatal sternal cleft associated with an extrathoracic cystic mass

This report describes an unusual case of cystic exophytic tumor associated with a complete sternal cleft. The tumor masked the presence of sternal cleft on prenatal ultrasound scan.

Antihypertensive drug treatment in chronic renal allograft rejection in the rat. Effect on structure and function

To gain insight into the contribution of immunologic and hemodynamic factors in the progressive demise of structure and function in chronic renal allograft dysfunction, we studied the histological changes, the immunostainable glomerular anionic sites, and glomerular capillary hydrostatic pressures of rat renal allografts with chronic rejection. Recipient animals were left untreated, received 8 weeks of treatment with the immunosuppressive drug cyclosporine, or received antihypertensive drugs consisting of the combination of reserpine, hydralazine and hydrochlorothiazide, the angiotensin-converting enzyme inhibitor cilazapril, or the angiotensin II receptor blocker L-158,809. Grafts in untreated recipients developed chronic interstitial inflammation, as well as vascular and glomerular lesions consistent with chronic rejection. These lesions were associated with immunohistochemical loss of the negatively charged heparan sulfate proteoglycan side chain. All treatment regimens decreased the systemic and glomerular capillary pressures and were associated with no loss of function, decreased proteinuria, and a tendency to improved graft function. Cyclosporine prevented all histological manifestations of rejection, and antihypertensive drugs decreased the extent of glomerular mesangiolysis and glomerulosclerosis; L-158,809 and cilazapril also inhibited graft atherosclerosis and tubular atrophy. We conclude that chronic rejection is primarily an immune-mediated process, but hemodynamic and angiotensin II-mediated effects may play a pivotal role in the expression of immune-mediated lesions.

Growth factor transcripts in rat renal transplants

Locally produced cytokines and growth factors may mediate tissue remodelling processes, as observed in renal transplants exposed to ischemia or acute rejection episodes. The present study was designed to investigate mRNA transcript levels of platelet-derived growth factor (PDGF)-receptor beta, PDGF-A, PDGF-B, fibroblast growth factor-1, and transforming growth factor beta 1 in normal rat kidneys, in kidneys following contralateral nephrectomy and in renal transplants with acute or chronic rejection. Platelet-derived growth factor-receptor beta mRNA levels increased significantly in syngeneic and allogeneic transplants in the first week after transplantation and in allogeneic transplants with chronic rejection. Immunohistochemistry showed induction of PDGF-receptor beta protein expression on vascular wall cells in such grafts. Platelet-derived growth factor-A chain mRNA levels increased in day 3 allografts and in syngeneic LEW grafts, while PDGF-B chain mRNA levels showed no significant changes with transplantation. Fibroblast growth factor-1 mRNA levels were detectable in normal kidneys, tended to decrease with acute rejection, and increased significantly in chronic rejection. Transforming growth factor-beta 1 transcripts increased in acute and chronic rejection; immunohistochemistry showed predominantly glomerular localization of the transforming growth factor-beta 1 protein. We conclude that transplantation and rejection are associated with changes in the intragraft mRNA levels for several growth factors; chronic rejection is characterized by an increase in fibroblast growth factor-1 and transforming growth factor-beta 1 transcript levels.

Esophageal replacement using the colon: is it a good choice?

Thirty-eight children (2 months to 26 years of age) underwent esophageal replacement at our institution between 1962 and 1993. Twenty-four patients had esophageal atresia, with the replacement performed at a mean age of 17 months. The remaining patients (37%) had strictures and were older (mean, 7.4 years). Replacement procedures involved the right colon in 61% of cases and the transverse left colon in the others (39%). Sixty-three percent were placed substernally and 37% were done in transthoracic fashion. The average length of stay in the hospital was 34 days (range, 11 to 256 days.) Early complications (within 30 days) included cervical anastomotic leaks (11 patients; 29%) pneumonia (4), would infection (2), pneumothorax/hemothorax (3), wound dehiscence (1), prolonged ventilation (2), vocal cord paralysis (1), Horner's syndrome (1), pancreatitis (1), and perforated graft (1). Despite the incidence of early leaks, only two persisted long-term (more than 3 months). Other late complications included significant proximal strictures (5), and cologastric strictures developed in five patients. Seven cases were considered graft failures (18%), and all of these eventually require graft replacement. Additional problems included redundant graft requiring revision (4) and dumping syndrome (2). There were six cases of intestinal obstruction caused by adhesions. Four of these involved intrathoracic obstruction of the graft and two involved small bowel obstruction. There was only one death, which occurred late and was not related to the primary disease or procedure. Long-term follow-up data were available for 20 patients (53%). The follow-up period ranged from 1 to 33 years (mean, 12 years). Fourteen had excellent results after the initial interposition, being able to eat and function well without any further intervention. Seven patients (18%) have had poor results and 17 (45%) required additional procedures to obtain good functional results. In our experience, the colon continues to be a good option for esophageal replacement, but additional procedures frequently are necessary to optimize the functional outcome. Good results can be expected in the majority of cases, but late problems (ie, redundant colon and poor emptying) are not unusual, and careful follow-up is essential in the management of such patients.

Endodermal sinus tumor in children

Malignant germ cell tumors account for about 3% of neoplasms in children, and endodermal sinus tumor (EST) is the most common histological subtype. The authors reviewed 22 years' experience (at their institution) in the management of 37 patients with this tumor. Fifteen of them (41%) had a sacrococcygeal primary, 10 had a testicular tumor (27%), 6 had an ovarian tumor (16%), 3 had a vaginal tumor (8%) and 3 had tumors at other sites (8%). Seven (19%) patients presented with metastatic disease, primarily pulmonary. The serum alpha-fetoprotein (AFP) level was elevated in all cases tested. The initial chemotherapy regimen included vincristine, actinomycin, cyclophosphamide (VAC), and Adriamycin (6 patients), but since 1985 the regimen has been changed to include cisplatin or Carboplatin, etoposide, and bleomycin (21 patients). Eight patients with testicular tumors initially were treated with surgical excision alone. Computed tomography results were a poor predictor of recurrence, but AFP surveillance was extremely sensitive. No second-look operation detected residual tumor in the absence of AFP elevation. Initial relapse for all patients tended to occur early (within 2 years), locally, and often with pulmonary metastases. Although historically the prognosis for patients with EST has been poor, the overall 2-year survival rate in this series was 70%. The best prognosis was among the children who had a testicular primary tumor (survival rate, 100%). The 2-year survival rate for patients with ovarian tumors was 67%; for those with sacrococcygeal primaries it was 60%. These results suggest that the prognosis for children with EST has improved significantly over the past decade. Contributing factors include therapy based on cisplatin, etoposide, and bleomycin, and relapse surveillance with serial AFP determinations. Second-look procedures should be reserved for patients who have an increasing level of serum AFP, suspicious computed tomography findings, and no obvious evidence of metastatic disease.