Advances in pediatric rhabdomyosarcoma characterization and disease model development.

Rhabdomyosarcoma (RMS), a form of soft tissue sarcoma, is one of the most common pediatric malignancies. A complex disease with at least three different subtypes, it is characterized by perturbations in a number of signaling pathways and genetic abnormalities. Extensive clinical studies have helped classify these tumors into high and low risk groups to facilitate different treatment regimens. Research into the etiology of the disease has helped uncover numerous potential therapeutic intervention points which can be tested on various animal models of RMS; both genetically modified models and tumor xenograft models. Taken together, there has been a marked increase in the survival rate of RMS patients but the highly invasive, metastatic forms of the disease continue to baffle researchers. This review aims to highlight and summarize some of the most important developments in characterization and in vivo model generation for RMS research, in the last few decades.

PDGFR-A is a therapeutic target in alveolar rhabdomyosarcoma.

Alveolar rhabdomyosarcoma is an aggressive skeletal muscle cancer of childhood. Our initial studies of rhabdomyosarcoma gene expression for patients enrolled in a national clinical trial suggested that platelet-derived growth factor receptor A (PDGFR-A) may be a mediator of disease progression and metastasis. Using our conditional mouse tumor models that authentically recapitulate the primary mutations and metastatic progression of alveolar rhabdomyosarcomas in humans, we found by immunoblotting and immunokinase assays that PDGFR-A and its downstream effectors, mitogen-activated protein kinase and Akt, were highly activated in both primary and metastatic tumors. Inhibition of PDGFR-A by RNA interference, small molecule inhibitor or neutralizing antibody had a dramatic effect on tumor cell growth both in vitro and in vivo, although resistance evolved in one-third of tumors. These results establish proof-of-principal for PDGFR-A as a therapeutic target in alveolar rhabdomyosarcoma.

PDK-1/AKT pathway as a novel therapeutic target in rhabdomyosarcoma cells using OSU-03012 compound.

Rhabdomyosarcoma (RMS) is the most common paediatric soft-tissue sarcoma including two major subtypes, alveolar rhabdomyosarcoma (ARMS) and embryonal rhabdomyosarcoma (ERMS). Increasing evidence suggests that oncogenesis of RMS involves multiple stages of signalling protein dysregulation which may include prolonged activation of serine/threonine kinases such as phosphoinositide-dependent kinase-1 (PDK-1) and AKT. To date, whether PDK-1/AKT pathway is activated in RMS is unknown. This study was to examine phosphorylation status of AKT and to evaluate a novel small molecular inhibitor, OSU-03012 targeting PDK-1 in RMS. We examined phosphorylation levels of AKT using ARMS and ERMS tissue microarray and immunohistochemistry staining. Our results showed phospho-AKT(Thr308) level is elevated 42 and 35% in ARMS and ERMS, respectively. Phospho-AKT(Ser473) level is also increased 43% in ARMS and 55% in ERMS. Furthermore, we showed that OSU-03012 inhibits cell viability and induces apoptosis in ARMS and ERMS cell lines (RH30, SMS-CTR), which express elevated phospho-AKT levels. Normal cells are much less sensitive to OSU-03012 and in which no detectable apoptosis was observed. This study showed, for the first time, that PDK-1/AKT pathway is activated in RMS and may play an important role in survival of RMS. PDK-1/AKT pathway may be an attractive therapeutic target for cancer intervention in RMS using OSU-03012.

Survivin-directed RNA interference cocktail is a potent suppressor of tumour growth in vivo.

BACKGROUND: Survivin is proposed to play a central role in the progression and resistance to therapy of diverse tumour types. High levels of this molecule in tumour cells also correlate with loss of the TP53 tumour suppressor gene, suggesting a molecular connection between TP53 loss and transcriptional induction of Survivin. Patients with TP53 germline mutations, such as those with Li-Fraumeni syndrome, are particularly susceptible to sarcomas, including rhabdomyosarcomas. Our study aimed to identify rhabdomyosarcoma tumours that express Survivin, in order to test novel Survivin-targeted therapies in these tumours. METHODS: Tumour microarray slides composed of 63 primary rhabdomyosarcoma tumours were stained with a polyclonal antibody to Survivin to identify tumours expressing Survivin. Subcutaneous tumours were then established in NOD/SCID mice using RH30(red) cells, a red fluorescent clone of the RH30 human alveolar rhabdomyosarcoma cell line. Tumours were treated by hydrodynamic injection with a cocktail of Survivin-shRNA-encoding plasmids for a period of 2 weeks. RESULTS: Over 80% of primary rhabdomyosarcoma tumours expressed Survivin. Treatment of rhabdomyosarcoma xenografts showed greater than 70% reduction in growth when compared with control injected tumours at study completion (average tumour sizes: 1683 v 304 mm3, p<0.05). CONCLUSIONS: Our findings support a role for Survivin in rhabdomyosarcoma biology and provide preliminary evidence for the therapeutic use of Survivin-targeted RNA interference for human tumours that express high levels of this molecule.

Establishing a tumour bank: banking, informatics and ethics.

The six divisions of the Cooperative Human Tissue Network in the USA bank and distribute tens of thousands of tissue specimens to researchers annually. Major operational concerns include: maintaining tissue integrity, managing informatics, and protecting patient confidentiality. Increasing molecular genetics testing is also resulting in an increased demand for high-quality nucleic acids.

Which patients with microscopic disease and rhabdomyosarcoma experience relapse after therapy? A report from the soft tissue sarcoma committee of the children's oncology group.

PURPOSE: To identify which patients with rhabdomyosarcoma and microscopic residual disease (group II) are likely to not respond to therapy. PATIENTS AND METHODS: Six hundred ninety-five patients with group II tumors received chemotherapy and 90% received radiation therapy on Intergroup Rhabdomyosarcoma Study (IRS)-I to IRS-IV (1972 to 1997). Tumors were subgrouped depending on the presence of microscopic residual disease only (subgroup IIa), resected positive regional lymph nodes, (subgroup IIb), or microscopic residual disease and resected positive regional lymph nodes (subgroup IIc). RESULTS: Overall, the 5-year failure-free survival rate (FFSR) was 73%, and patients with embryonal rhabdomyosarcoma treated on IRS-IV fared especially well (5-year FFSR, 93%; n = 90). Five-year FFSRs differed significantly by subgroup (IIa, 75% and n = 506; IIb, 74% and n = 101; IIc, 58% and n = 88; P = .0037) and treatment (IRS-I, 68%; IRS-II, 67%; IRS-III, 75%; IRS-IV, 87%; P < .001). Multivariate analysis revealed positive associations between primary site (favorable), histology (embryonal), subgroup IIa or IIb, treatment (IRS-III/IV), and better FFSRs. Patterns of treatment failure revealed local failure to be 8%, regional failure, 4%, and distant failure, 14%. The relapse pattern noted over the course of IRS-I to IRS-IV shows a decrease in the systemic relapse rates, particularly for patients with embryonal histology, suggesting that improvement in FFSRs is primarily a result of improved chemotherapy. CONCLUSION: Group II rhabdomyosarcoma has an excellent prognosis with contemporary therapy as used in IRS-III/IV, and those less likely to respond can be identified using prognostic factors: histology, subgroup, and primary site. Patients with embryonal rhabdomyosarcoma are generally cured, although patients with alveolar rhabdomyosarcoma or undifferentiated sarcoma, particularly subgroup IIc at unfavorable sites, continue to need better therapy.

Results from the IRS-IV randomized trial of hyperfractionated radiotherapy in children with rhabdomyosarcoma--a report from the IRSG.

PURPOSE: To evaluate the outcome and toxicity of hyperfractionated radiotherapy (HFRT) vs. conventionally fractionated radiotherapy (CFRT) in children with Group III rhabdomyosarcoma (RMS). METHODS AND MATERIALS: Five hundred fifty-nine children were enrolled into the Intergroup Rhabdomyosarcoma Study IV with Group III RMS. Sixty-nine were ineligible for the analysis because of incorrect group or pathologic findings. Of the 490 remaining, 239 were randomized to HFRT (59.4 Gy in 54 1.1-Gy twice daily fractions) and 251 to CFRT (50.4 Gy in 28 1.8-Gy daily fractions). The age range was <1-21 years. All patients received chemotherapy. RT began at Week 9 after induction chemotherapy for all but those with high-risk parameningeal tumors who received RT during induction chemotherapy. The patient groups were equally balanced. The median follow-up was 3.9 years. RESULTS: Analysis by randomized treatment assignment (intent to treat) revealed an estimated 5-year failure-free survival (FFS) rate of 70% and overall survival (OS) of 75%. In the univariate analysis, the factors associated with the best outcome were age 1-9 years at diagnosis; noninvasive tumors; tumor size <5 cm; uninvolved lymph nodes; Stage 1 or 2 disease; primary site in the orbit or head and neck; and embryonal histologic features (p = 0.001 for all factors). No differences in the FFS or OS between the two RT treatment methods and no differences in the FFS or OS between HFRT and CFRT were found when analyzed by age, gender, tumor size, tumor invasiveness, nodal status, histologic features, stage, or primary site. Treatment compliance differed by age. Of the children <5 years, 57% assigned to HFRT received HFRT and 77% assigned to CFRT received CFRT. Of the children >or=5 years, 88% assigned to both HFRT and CFRT received their assigned treatment. The reasons for not receiving the appropriate randomized treatment were progressive disease, early death, parent or physician refusal, young age, or surgery. The toxicity assessment revealed more mucositis with HFRT (66%) than with CFRT (46%) (p = 0.03) for the parameningeal patients, and more skin reactions (16%) and nausea/vomiting (13%) with HFRT than with CFRT (7% and 5%, respectively) for patients with nonparameningeal primary tumors (p = 0.03 and p = 0.02, respectively). The analysis by treatment actually received revealed a 5-year FFS rate of 73% and OS rate of 77%, with no difference between CFRT and HFRT. As well, there was no difference in FFS or OS between CFRT and HFRT when analyzed by age, gender, tumor size, tumor invasiveness, modal status, histology, stage or site of primary. The 5-year estimated cumulative incidence of failure for the irradiated patients was local, 13%; regional, 3%; and distant, 13%; with no differences between HFRT and CFRT. The 5-year local failure rate by site was orbit, 5%; head and neck, 12%; parameningeal, 16%; bladder/prostate, 19%; extremity, 7%; and all others, 14%. The 5-year regional failure rate was parameningeal,1%; extremity, 20%; and all others, 5%. The 5-year distant failure rate was orbit, 2%; head and neck, 6%; parameningeal, 11%; bladder/prostate, 15%; extremity, 28%; and all others, 17%. CONCLUSIONS: HFRT, as given in this study, did not improve local/regional control, FFS, or OS compared with CFRT. The risk of local/regional failure was comparable to that of distant failure in children with Group III RMS. The standard of care for Group III RMS continues to be CFRT with chemotherapy.

Controversies in the management of paratesticular rhabdomyosarcoma: is staging retroperitoneal lymph node dissection necessary for adolescents with resected paratesticular rhabdomyosarcoma?

PURPOSE: Use of retroperitoneal lymph node dissection (RPLND) in paratesticular rhabdomyosarcoma (PTRMS) is controversial and has changed over the past 2 decades. The Intergroup Rhabdomyosarcoma Study Group (IRSG) required ipsilateral RPLND (IRPLND) for all patients with PTRMS treated on IRS-III (1984-91), but changed to clinical evaluation of RPLNs using computerized tomography (CT) in IRS-IV (1991 through 1997). In IRS-IV, only those patients with identified lymph node involvement on CT required surgical evaluation of the RPLNs. Nodal radiation therapy was administered only to patients with RPLNs recognized as positive; such patients received more intensive chemotherapy as well. Thus, they compared the incidence of recognized RPLN involvement using these 2 different approaches. They then analyzed patient outcome to determine whether this change in management affected outcome. METHODS: Eligible patients with group I or II PTRMS who were treated on IRS III (n = 100) or IRS IV (n = 134) were analyzed. Failure-free survival (FFS) and survival (S) rates were estimated using the Kaplan-Meier method and compared using the log-rank test. RESULTS: There was a significant change in the distribution of patients with group I versus II tumors from IRS-III to IRS-IV (group I, 68% in IRS-III versus 82% in IRS-IV). This was the result of decreased node recognition when CT was used to stage RPLNs in IRS-IV and was most notable for adolescents (>10 years of age). Overall, 3-year FFS was 92% for patients treated on IRS-III and 86% for those treated on IRS-IV (P =.10), whereas survival estimates were 96% and 92%, respectively (P =.30). Adolescents were at higher risk of RPLN relapse than were children (<10 years of age) and their FFS and survival were worse, regardless of IRS protocol. Furthermore, adolescents with recognized group II tumors experienced better 3-year FFS than those with group I tumors on IRS-IV (100% versus 68%, P =.06), most likely as a result of receiving radiotherapy and intensified chemotherapy. CONCLUSIONS: Use of only CT scan evaluation of RPLN in IRS-IV led to a decrease in identification of RPLN involvement in boys who present with localized PTRMS, and a higher rate of regional relapse as compared with IRS-III. Adolescents had much higher likelihood of RPLN disease, and they fared significantly worse than did younger children on both studies. Furthermore, adolescent boys with group I tumors experienced worse FFS than those with Group II tumors on IRS-IV, probably because some patients with group II tumors were not identified by CT imaging and thus received less effective therapy. These data suggest that adolescents should have ipsilateral RPLN dissection as part of their routine staging, and those with positive lymph nodes require intensified chemotherapy as well as nodal irradiation.

Cerebrospinal fluid gastrin releasing peptide in the diagnosis of leptomeningeal metastases from small cell carcinoma.

BACKGROUND: The clinical diagnosis of leptomeningeal metastases is often difficult to substantiate. Patients with an underlying malignancy typically present with neurologic symptoms referable to multiple levels of the neuraxis. Although most patients have an abnormal cerebrospinal fluid (CSF), less than 60% have evidence of malignant cells on cytologic examination from a single lumbar puncture, and the disease is usually advanced in patients with positive results. An elevated serum level of gastrin releasing peptide (GRP) in patients with small cell carcinoma has emerged as one of the most useful markers for disease activity. METHODS: A patient with small cell carcinoma presented with signs of meningitis and an abnormal CSF. However, the CSF gave repeatedly negative cytologic results. Hence, serum and CSF were analyzed for GRP. RESULTS: The CSF GRP level was elevated by more than six orders of magnitude above the serum level. An autopsy demonstrated extensive meningeal and parenchymal brain involvement by small cell carcinoma. CONCLUSIONS: The diagnosis of leptomeningeal metastases in patients with small cell carcinoma can be established by CSF GRP testing, even when cytologic examination is negative.

Improved outcome for patients with middle ear rhabdomyosarcoma: a children's oncology group study.

PURPOSE: The goal of this study was to define the clinical features and optimal therapy for children and adolescents with middle ear (ME) rhabdomyosarcoma (RMS). PATIENTS AND METHODS: We reviewed demographic data, clinical features, therapy (including chemotherapy, surgery, and radiation), and outcome for the 179 eligible patients with ME RMS who were enrolled onto Intergroup Rhabdomyosarcoma Studies (IRS) I through IV or pilot studies between November 1972 and December 1997. RESULTS: Most patients were younger than 10 years old (90%), and 63% were male. Because of the parameningeal location, most tumors were not resected before chemotherapy (group I, < 1%; group II, 4%; group III, 84%; group IV, 12%). Although most tumors were locally invasive (T2, 89%), the majority were small (< or = 5 cm, 66%), lacked nodal metastases (N0, 86%), and had embryonal histology (85%). The 5-year failure-free survival (FFS) and overall survival (OS) estimates were 67% and 72%, respectively. Both FFS and OS improved significantly over the course of IRS I through IV (3-year FFS and OS: IRS-I, 42% and 42%; IRS-II, 70% and 74%; IRS-III, 65% and 72%; IRS-IV pilot, 81% and 96%; IRS-IV, 88% and 88%, P <.001). Lower clinical group or stage and smaller tumor size were associated with better outcome. Age, sex, tumor invasiveness, and nodal metastases were not predictive of outcome. CONCLUSION: Patients with ME RMS generally present with small, unresectable, invasive tumors at a site traditionally considered prognostically unfavorable. Nevertheless, such patients have benefited markedly from improvements in multimodal, risk-based therapy during the course of IRS I through IV, and with contemporary therapy, most are cured.

Intergroup rhabdomyosarcoma study-IV: results for patients with nonmetastatic disease.

PURPOSE: The study goal was to improve outcome in children with rhabdomyosarcoma by comparing risk-based regimens of surgery, radiotherapy (RT) and chemotherapy. PATIENTS AND METHODS: Eight hundred eighty-three previously untreated eligible patients with nonmetastatic rhabdomyosarcoma entered the Intergroup Rhabdomyosarcoma Study-IV (IRS-IV) (1991 to 1997) after surgery and were randomized treatment by primary tumor site, group (1 to 3), and stage (I to III). Failure-free survival (FFS) rates and survival were the end points used in comparisons between randomized groups and between patient subgroups treated on IRS-III and IRS-IV. Most patients were randomized to receive vincristine and dactinomycin (VA) and cyclophosphamide (VAC, n = 235), or VA and ifosfamide (VAI, n = 222), or vincristine, ifosfamide, and etoposide (VIE, n = 236). Patients with group 3 tumors were randomized to receive conventional RT (C-RT) versus hyperfractionated RT (HF-RT). RESULTS: Overall 3-year FFS and survival were 77% and 86%, respectively. Three-year FFS rates with VAC, VAI, and VIE were 75%, 77%, and 77%, respectively (P =.42). No significant difference in outcome was noted with HF-RT versus C-RT (P =.85 and P =.90, respectively). Overall, patients with embryonal tumors benefited from intensive three-drug chemotherapy in IRS-IV (3-year FFS, 83%). The improvement was seen for patients with stage I or stage II/III, group 1/2 disease, many of whom received VA chemotherapy on IRS-III. Patients with stage 2/3, group 3 disease had similar outcomes on IRS-III and IRS-IV. Three-year FFS for the nonrandomized patient subsets was 75% with renal abnormalities; 81% for paratesticular, group 1 cases; and 91% for group 1/2 orbit or eyelid tumors. Patients with paratesticular primaries had poorer outcomes if they were more than 10 years old (3-year FFS, 63% v 90%). Myelosuppression occurred in most patients, but toxic deaths occurred in less than 1%. CONCLUSION: VAC and VAI or VIE with surgery (with or without RT), are equally effective for patients with local or regional rhabdomyosarcoma and are more effective for embryonal tumors than therapies used previously. Younger patients with group 1 paratesticular embryonal tumors and all patients with group 1/2 orbit or eyelid tumors can usually be cured with VA chemotherapy along with postoperative RT for group 2 disease.

The Intergroup Rhabdomyosarcoma Study Group (IRSG): Major Lessons From the IRS-I Through IRS-IV Studies as Background for the Current IRS-V Treatment Protocols.

Purpose. To enumerate lessons from studying 4292 patients with rhabdomyosarcoma (RMS) in the Intergroup Rhabdomyosarcoma Study Group (IRSG, 1972-1997).Patients. Untreated patients < 21 years of age at diagnosis received systemic chemotherapy, with or without irradiation (XRT) and/or surgical removal of the tumor.Methods. Pathologic materials and treatment were reviewed to ascertain compliance and to confirm response and relapse status.Results. Survival at 5 years increased from 55 to 71% over the period. Important lessons include the fact that extent of disease at diagnosis affects prognosis. Re-excising an incompletely removed tumor is worthwhile if acceptable form and function can be preserved. The eye, vagina, and bladder can usually be saved. XRT is not necessary for children with localized, completely excised embryonal RMS. Hyperfractionated XRT has thus far not produced superior local control rates compared with conventional, once-daily XRT. Patients with non-metastatic cranial parameningeal sarcoma can usually be cured with localized XRT and systemic chemotherapy, without whole-brain XRT and intrathecal drugs. Adding doxorubicin, cisplatin, etoposide, and ifosfamide has not significantly improved survival of patients with gross residual or metastatic disease beyond that achieved with VAC (vincristine, actinomycin D, cyclophosphamide) and XRT. Most patients with alveolar RMS have a tumor-specific translocation. Mature rhabdomyoblasts after treatment of patients with bladder rhabdomyosarcoma are not necessarily malignant, provided that the tumor has shrunk and malignant cells have disappeared.Discussion. Current IRSG-V protocols, summarized herein, incorporate recommendations for risk-based management. Two new agents, topotecan and irinotecan, are under investigation for patients who have an intermediate or high risk of recurrence.

Rhabdomyosarcoma and undifferentiated sarcoma in the first two decades of life: a selective review of intergroup rhabdomyosarcoma study group experience and rationale for Intergroup Rhabdomyosarcoma Study V.

PURPOSE: To review the importance of prognostic factors in developing new protocols for children with rhabdomyosarcoma (RMS). PATIENTS AND METHODS: Four studies conducted by the Intergroup Rhabdomyosarcoma Study (IRS) Group from 1972 through 1991. RESULTS: Favorable prognostic factors are: (1) undetectable distant metastases at diagnosis; (2) primary sites in the orbit and nonparameningeal head/neck and genitourinary nonbladder/prostate regions; (3) grossly complete surgical removal of localized tumor at the time of diagnosis; (4) embryonal/botryoid histology; (5) tumor size < or = 5 cm; and (6) age younger than 10 years at diagnosis. The IRS-V protocols are risk-based and refine therapy by reducing exposure to cyclophosphamide and radiation therapy (XRT) in patients at low risk while adding new, active agents such as topotecan or irinotecan to the standard therapy of vincristine, actinomycin D, and cyclophosphamide (VAC) plus XRT for patients with unfavorable histology or advanced disease. Collection of biologic specimens from patients with newly diagnosed disease continues to identify other factors that may distinguish patients with favorable features from those who need more intensive therapy. A new protocol that takes into account their previous treatment is needed for patients with recurrent disease. This program (being planned) does not include bone marrow/stem cell reconstitution because this strategy has thus far failed to improve survival rates of patients with metastases at diagnosis. CONCLUSION: Better understanding of biologic differences and new, active agents are needed to improve outcome of patients with unfavorable features at presentation.

Benefit of intensified therapy for patients with local or regional embryonal rhabdomyosarcoma: results from the Intergroup Rhabdomyosarcoma Study IV.

PURPOSE: To compare failure-free survival (FFS) and survival for patients with local or regional embryonal rhabdomyosarcoma treated on the Intergroup Rhabdomyosarcoma Study (IRS)-IV with that of comparable patients treated on IRS-III. PATIENTS AND METHODS: Patients were retrospectively classified as low- or intermediate-risk. Low-risk patients were defined as those with primary tumors at favorable sites, completely resected or microscopic residual, or orbit/eyelid primaries with gross residual disease and tumors less than 5 cm at unfavorable sites but completely resected. Intermediate-risk patients were all other patients with local or regional tumors. RESULTS: Three-year FFS improved from 72% on IRS-III to 78% on IRS-IV for patients with intermediate-risk embryonal rhabdomyosarcoma (P =.02). Subset analysis revealed two groups that benefited most from IRS-IV therapy. FFS at 3 years for patients with resectable node-positive or unresectable (group III) embryonal rhabdomyosarcoma arising at certain favorable sites (head and neck [not orbit/eyelid or parameningeal] and genitourinary [not bladder or prostate]) improved from 72% on IRS-III to 92% on IRS-IV (P =.01). Similarly, 3-year FFS for patients with completely resected tumor or with only microscopic disease remaining (group I or II) at unfavorable sites improved from 71% on IRS-III to 86% on IRS-IV (P =.04). Only patients with unresectable embryonal rhabdomyosarcoma (group III) at unfavorable sites had no improvement in outcome on IRS-IV (3-year FFS for IRS-III and IRS-IV, 72% and 75%, respectively; P =.31). CONCLUSION: IRS-IV therapy benefited certain subgroups of patients with intermediate-risk embryonal rhabdomyosarcoma. A doubling of the intensity of cyclophosphamide (or ifosfamide equivalent) dosing per cycle between IRS-III and IRS-IV is thought to be a key contributing factor for this improvement.

Clinicopathologic study of ectomesenchymomas from Intergroup Rhabdomyosarcoma Study Groups III and IV.

Ectomesenchymomas (EM) are rare malignant neoplasms usually consisting of rhabdomyosarcoma (RMS) with a neural component. Only 21 cases have been previously reported. Here we extend the clinicopathologic spectrum of EM by describing our findings in 15 cases. Only 5 patients were infants; 10 were < or =3 years old and 5 were > or =6 years old. No male predilection was observed; 7 were female. The originating institutional diagnoses were; RMS (12), undifferentiated sarcoma (1), or EM (2), suggesting underdiagnosis of this entity. The primary tumor sites included external genital (5), pelvis/abdomen (6), head and neck (3), and extremity (1). The size of the primary neoplasm was usually > or =5 cm at diagnosis but dissemination only occurred in a minority. Local infiltration was not uncommon. These neoplasms were typically multilobate, thinly encapsulated, hemorrhagic, and necrotic. Light microscopic features were highly variable, but embryonal RMS with scattered or clustered ganglion cells, often in lacunae, was characteristic. In some cases, primitive neuroblastic or neuroectodermal areas were found and/or a component of alveolar RMS was seen. Focal anaplasia was occasionally observed. Mitotic activity appears higher than previously appreciated and some necrosis was invariably present. Electron microscopy was performed in 11 cases, which confirmed skeletal muscle +/- neural differentiation. Cytogenetic studies performed in five cases revealed no specific abnormality. Monoclonal neuron-specific enolase was the best marker of ganglion cells and primitive neural elements. MIC-2 (CD99) membrane expression was not definitively present in any of the six cases examined. A number of the above parameters appear to be of some prognostic significance, but overall, these neoplasms appear to have a similar outcome as would be predicted for their RMS element alone (exclusive of any neural component), with respect to the RMS subtype, age of the patient, and anatomic location of the neoplasm.

Somatostatin receptor gene expression in neuroblastoma.

Somatostatin receptor expression is a favorable prognostic factor in human neuroblastoma. Somatostatin receptors have been demonstrated in vitro by pharmacologic analysis of tumor tissue and in vivo by diagnostic radioreceptor scintigraphy. However, which receptor subtypes (sst(1), sst(2), sst(3), sst(4), and sst(5)) are expressed in these tumors has not yet been delineated. We used RT-PCR to analyze expression of the five somatostatin receptor genes in 32 neuroblastoma tumor specimens. All 32 tumor specimens expressed mRNA for c-abl and sst(1); sst(2) mRNA was detected in 27/32 samples and somatostatin mRNA was detected in 30/32 tumor specimens. The remaining receptor subtypes, sst(3), sst(4), and sst(5) were variably expressed. Receptor protein for sst(1) and sst(2) was visualized in tumor neuroblasts as well as in endothelial cells of tumor vessels using immunostaining with specific anti-receptor antibodies. The effect of high expression of somatostatin receptors on cell proliferation was examined in SKNSH neuroblastoma cells transfected with sst(1) and sst(2). SS(14) binding to wild-type SKNSH cells was undetectable; but the native peptide bound with high affinity to the SKNSH/sst(1) and SKNSH/sst(2) neuroblastoma cell lines. Pharmacologic analysis of binding with two long-acting analogues, CH275 and octreotide, confirmed selective expression of sst(1) and sst(2) in stably transfected SKNSH cells. Formation of neuroblastoma xenograft tumors in nude mice was significantly delayed for both SKNSH/sst(1) (P<0.001) and SKNSH/sst(2) (P<0.05) cells compared to wild-type SKNSH. We conclude that: (1) Somatostatin receptors, sst(1) and sst(2), are expressed in the majority of neuroblastomas at diagnosis; and (2) upregulation of functional sst(1) or sst(2) in neuroblastoma cell lines suppresses tumorigenicity in a xenograft model. These observations suggest that somatostatin receptors may be a useful therapeutic target in neuroblastoma.

Indications for radiotherapy and chemotherapy after complete resection in rhabdomyosarcoma: A report from the Intergroup Rhabdomyosarcoma Studies I to III.

PURPOSE: To evaluate the outcome of patients with rhabdomyosarcoma (RMS) treated with complete surgical resection and multiagent chemotherapy, with or without local radiotherapy (RT). PATIENTS AND METHODS: Four hundred thirty-nine patients with completely resected (ie, group I) RMS were further treated with chemotherapy (vincristine and actinomycin D +/- cyclophosphamide, doxorubicin, and cisplatin) on Intergroup Rhabdomyosarcoma Studies (IRS) I to III between 1972 and 1991. Eighty-three patients (19%) also received local RT as a component of initial treatment. RESULTS: Eighty-six patients relapsed (10-year failure-free survival [FFS] 79%, overall survival 89%). Six percent of failure sites were local, 6% were regional, and 7% were distant. Poor prognostic factors were tumor size greater than 5 cm, alveolar or undifferentiated histology, primary tumor sites other than genitourinary, and treatment on IRS-I or II. For patients with embryonal RMS who were treated with RT, there was a trend for improved FFS but no difference in overall survival. On IRS-I and II, patients with alveolar or undifferentiated sarcoma who received RT compared with those who did not receive RT had greater 10-year FFS rates (73% v 44%, respectively; P =.03) and overall survival rates (82% v 52%, respectively; (P =.02). Such patients who received RT on IRS III also benefited more than those who did not receive RT (10-year FFS, 95% v 69%; P =.01; overall survival, 95% v 86%; P =.23). CONCLUSION: Patients with group I embryonal RMS have an excellent prognosis when treated with adjuvant multiagent chemotherapy without RT. Patients with alveolar RMS or undifferentiated sarcoma fare worse; however, FFS and overall survival are substantially improved when RT is added to multiagent chemotherapy (IRS-I and II). The best outcome occurred in IRS-III, when RT was used in conjunction with intensified chemotherapy.

Survival after relapse in children and adolescents with rhabdomyosarcoma: A report from the Intergroup Rhabdomyosarcoma Study Group.

BACKGROUND: Despite advances in therapy, nearly 30% of children with rhabdomyosarcoma experience progressive or relapsed disease, which is often fatal. PATIENTS AND METHODS: To facilitate the development of a retrieval therapy protocol, we studied potential risk factors that were predictive of survival after first relapse in 605 children who were enrolled onto three consecutive Intergroup Rhabdomyosarcoma Study Group protocols. RESULTS: The median survival time from first recurrence was 0.8 years; the estimated percentage of patients who survived 5 years from first recurrence was 17% +/- 2% (mean +/- SD). Univariate analysis showed that tumor histology was an important predictor of 5-year survival (P <.001): the 5-year survival rate was 64% for patients with botryoid tumors (n = 19), 26% for patients with embryonal tumors (n = 313), and 5% for patients with alveolar or undifferentiated sarcoma (n = 273). Further analysis identified prognostic factors within histologic subtypes (P <.001). For patients with embryonal tumors, the estimated 5-year survival rate was 52% for patients who initially presented with stage 1 or group I disease, 20% for those with stage 2/3 or group II/III disease, and 12% for those with group IV disease. For patients with stage 1/group I disease, estimated 5-year survival rates were higher for patients with local (72%) or regional (50%) recurrence than for those with distant (30%) recurrence. Among patients with alveolar or undifferentiated sarcoma, only the disease group predicted outcome: the 5-year survival estimate was 40% for group I versus 3% for groups II through IV. We identified a "favorable risk" group (approximately 20% of patients) whose 5-year estimated survival rate was near 50%; for all other patients, the estimated survival was near 10%. CONCLUSION: This analysis demonstrates that the probability of 5-year survival after relapse for rhabdomyosarcoma is dependent on several factors at the time of initial diagnosis, including histologic subtype, disease group, and stage. These findings will form the basis of a multi-institutional risk-adapted relapse protocol for childhood rhabdomyosarcoma.

Diagnosis of hirschsprung disease using the rectal biopsy: multi-institutional survey.

Diagnostic pathologists remain uncomfortable with the diagnosis of Hirschsprung disease (HD) via rectal (mucosal/submucosal) biopsy and with performance and interpretation of the associated acetylcholinesterase (AChE) assay. This report details the different diagnostic approaches taken by four major pediatric institutions-Children's Hospital, Columbus, OH; Children's Hospital Medical Center, Cincinnati, OH; Children's Hospital, Pittsburgh, PA; Children's Hospital, Los Angeles, CA-in confirming or excluding the presence of HD. The Columbus approach emphasizes serial morphologic examination of rectal biopsies, while Cincinnati emphasizes the primary diagnostic utility of the AChE stain. Pittsburgh and Los Angeles emphasize a detailed gross and microscopic analysis of rectal biopsies to detect both conventional HD and its more rare subtypes. The diagnostic approaches of these four institutions can be used on a complementary basis to the advantage of the general diagnostic pathologist, especially in HD cases with subtle clinical presentations. The need for careful and continual communication between the clinician and pathologist in diagnosing or excluding the presence of HD is imperative.