Stephen J. Qualman

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.

PAX3-FKHR and PAX7-FKHR Gene Fusions Are Prognostic Indicators in Alveolar Rhabdomyosarcoma: A Report From the Children’s Oncology Group

PURPOSE Alveolar rhabdomyosarcoma (ARMS) is an aggressive soft tissue malignancy of children and adolescents. Most ARMS patients express PAX3-FKHR or PAX7-FKHR gene fusions resulting from t(2;13) or t(1;13) translocations, respectively. We wished to confirm the diagnostic specificity of gene fusion detection in a large cohort of RMS patients and to evaluate whether these alterations influence clinical outcome in ARMS. PATIENTS AND METHODS We determined PAX3-FKHR or PAX7-FKHR fusion status in 171 childhood rhabdomyosarcoma (RMS) patients entered onto the Intergroup Rhabdomyosarcoma Study IV, including 78 ARMS patients, using established reverse transcriptase polymerase chain reaction assays. All patients received central pathologic review and were treated using uniform protocols, allowing for meaningful outcome analysis. We examined the relationship between gene fusion status and clinical outcome in the ARMS cohort. RESULTS PAX3-FKHR and PAX7-FKHR fusion transcripts were detected in 55% and 22% of ARMS patients, respectively; 23% were fusion-negative. All other RMS patients lacked transcripts, confirming the specificity of these alterations for ARMS. Fusion status was not associated with outcome differences in patients with locoregional ARMS. However, in patients presenting with metastatic disease, there was a striking difference in outcome between PAX7-FKHR and PAX3-FKHR patient groups (estimated 4-year overall survival rate of 75% for PAX7-FKHR v 8% for PAX3-FKHR; P =.0015). Multivariate analysis demonstrated a significantly increased risk of failure (P =.025) and death (P =.019) in patients with metastatic disease if their tumors expressed PAX3-FKHR. Among metastatic ARMS, bone marrow involvement was significantly higher in PAX3-FKHR-positive patients. CONCLUSION Not only are PAX-FKHR fusion transcripts specific for ARMS, but expression of PAX3-FKHR and PAX7-FKHR identifies a very high-risk subgroup and a favorable outcome subgroup, respectively, among patients presenting with metastatic ARMS.

NF-κB–YY1–miR-29 Regulatory Circuitry in Skeletal Myogenesis and Rhabdomyosarcoma

Studies support the importance of microRNAs in physiological and pathological processes. Here we describe the regulation and function of miR-29 in myogenesis and rhabdomyosarcoma (RMS). Results demonstrate that in myoblasts, miR-29 is repressed by NF-kappaB acting through YY1 and the Polycomb group. During myogenesis, NF-kappaB and YY1 downregulation causes derepression of miR-29, which in turn accelerates differentiation by targeting its repressor YY1. However, in RMS cells and primary tumors that possess impaired differentiation, miR-29 is epigenetically silenced by an activated NF-kappaB-YY1 pathway. Reconstitution of miR-29 in RMS in mice inhibits tumor growth and stimulates differentiation, suggesting that miR-29 acts as a tumor suppressor through its promyogenic function. Together, these results identify a NF-kappaB-YY1-miR-29 regulatory circuit whose disruption may contribute to RMS.

Prognostic Factors and Clinical Outcomes in Children and Adolescents With Metastatic Rhabdomyosarcoma--A Report From the Intergroup Rhabdomyosarcoma Study IV

PURPOSE To identify risk factors associated with outcomes in children with metastatic rhabdomyosarcoma (RMS) treated on the fourth Intergroup Rhabdomyosarcoma Study (IRS-IV). PATIENTS AND METHODS Patients with metastatic RMS were treated with one of two regimens that incorporated a window of either ifosfamide and etoposide (IE) with vincristine, dactinomycin, and cyclophosphamide (VAC) or vincristine, melphalan (VM) and VAC. Study end points were failure-free survival (FFS) and overall survival (OS). Clinical factors including age, histology, sites of primary and metastatic disease, and number of sites of metastatic disease were correlated with those end points. RESULTS One hundred twenty-seven patients were eligible for analysis. The estimated 3-year OS and FFS for all patients were 39% and 25%, respectively. By univariate analysis, 3-year OS was significantly influenced by histology (47% for embryonal v 34% for all others, P =.026) and increasing number of metastatic sites (P =.028). By multivariate analysis, the presence of two or fewer metastatic sites was the only significant predictor (P =.007 and.006, respectively). The combination of embryonal histology with two or fewer metastatic sites identified a subgroup with 3-year FFS of 40% and OS of 47%. CONCLUSION Children with group IV RMS treated on the IRS-IV study had improved OS and FFS if they had two or fewer metastatic sites and embryonal histology. This favorable subset of patients has outcomes approaching those observed in selected patients with localized, nonmetastatic disease. Thus, these patients might not be appropriate candidates for regimens that include experimental agents with substantial toxicities or unproven antitumor activity.

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 ≤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.

Phosphoprotein Pathway Mapping: Akt/Mammalian Target of Rapamycin Activation Is Negatively Associated with Childhood Rhabdomyosarcoma Survival

Mapping of protein signaling networks within tumors can identify new targets for therapy and provide a means to stratify patients for individualized therapy. Despite advances in combination chemotherapy, the overall survival for childhood rhabdomyosarcoma remains approximately 60%. A critical goal is to identify functionally important protein signaling defects associated with treatment failure for the 40% nonresponder cohort. Here, we show, by phosphoproteomic network analysis of microdissected tumor cells, that interlinked components of the Akt/mammalian target of rapamycin (mTOR) pathway exhibited increased levels of phosphorylation for tumors of patients with short-term survival. Specimens (n = 59) were obtained from the Childrens Oncology Group Intergroup Rhabdomyosarcoma Study (IRS) IV, D9502 and D9803, with 12-year follow-up. High phosphorylation levels were associated with poor overall and poor disease-free survival: Akt Ser(473) (overall survival P < 0.001, recurrence-free survival P < 0.0009), 4EBP1 Thr(37/46) (overall survival P < 0.0110, recurrence-free survival P < 0.0106), eIF4G Ser(1108) (overall survival P < 0.0017, recurrence-free survival P < 0.0072), and p70S6 Thr(389) (overall survival P < 0.0085, recurrence-free survival P < 0.0296). Moreover, the findings support an altered interrelationship between the insulin receptor substrate (IRS-1) and Akt/mTOR pathway proteins (P < 0.0027) for tumors from patients with poor survival. The functional significance of this pathway was tested using CCI-779 in a mouse xenograft model. CCI-779 suppressed phosphorylation of mTOR downstream proteins and greatly reduced the growth of two different rhabdomyosarcoma (RD embryonal P = 0.00008; Rh30 alveolar P = 0.0002) cell lines compared with controls. These results suggest that phosphoprotein mapping of the Akt/mTOR pathway should be studied further as a means to select patients to receive mTOR/IRS pathway inhibitors before administration of chemotherapy.

Identification of FGFR4-activating mutations in human rhabdomyosarcomas that promote metastasis in xenotransplanted models

Rhabdomyosarcoma (RMS) is a childhood cancer originating from skeletal muscle, and patient survival is poor in the presence of metastatic disease. Few determinants that regulate metastasis development have been identified. The receptor tyrosine kinase FGFR4 is highly expressed in RMS tissue, suggesting a role in tumorigenesis, although its functional importance has not been defined. Here, we report the identification of mutations in FGFR4 in human RMS tumors that lead to its activation and present evidence that it functions as an oncogene in RMS. Higher FGFR4 expression in RMS tumors was associated with advanced-stage cancer and poor survival, while FGFR4 knockdown in a human RMS cell line reduced tumor growth and experimental lung metastases when the cells were transplanted into mice. Moreover, 6 FGFR4 tyrosine kinase domain mutations were found among 7 of 94 (7.5%) primary human RMS tumors. The mutants K535 and E550 increased autophosphorylation, Stat3 signaling, tumor proliferation, and metastatic potential when expressed in a murine RMS cell line. These mutants also transformed NIH 3T3 cells and led to an enhanced metastatic phenotype. Finally, murine RMS cell lines expressing the K535 and E550 FGFR4 mutants were substantially more susceptible to apoptosis in the presence of a pharmacologic FGFR inhibitor than the control cell lines expressing the empty vector or wild-type FGFR4. Together, our results demonstrate that mutationally activated FGFR4 acts as an oncogene, and these are what we believe to be the first known mutations in a receptor tyrosine kinase in RMS. These findings support the potential therapeutic targeting of FGFR4 in RMS.

Intergroup Rhabdomyosarcoma Study: Update for Pathologists

ABSTRACT Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma of childhood, and 75% of such cases in the United States are reviewed at the Pathology Center for the Intergroup Rhabdomyosarcoma Study Group (IRSG). The first four generations of IRSG therapeutic trials (IRS I–IV) and supportive pathologic studies have generated a new International Classification of Rhabdomyosarcoma (ICR) that offers new morphologic concepts to the practicing pathologist. The objective of this report is to clearly define emerging histopathologic categories of RMS as defined by the ICR, and to emphasize correlative immunohistochemical or molecular studies. Emerging ICR variants of RMS place the patient in widely divergent prognostic categories (superior, botryoid or spindle cell variants; poor, solid alveolar or diffusely anaplastic variants). The cardinal histopathologic features of the ICR combined with results of studies of fusion genes seen with t(1;13) and t(2;13) will help delineate therapeutic subgroups of RMS for the fifth generation (IRS V) of IRSG studies. Consequently, it is imperative for the practicing pathologist to be familiar with the practical workup and diagnosis of RMS in childhood.

Molecular Classification of Rhabdomyosarcoma—Genotypic and Phenotypic Determinants of Diagnosis: A Report from the Children's Oncology Group

Rhabdomyosarcoma (RMS) in children occurs as two major histological subtypes, embryonal (ERMS) and alveolar (ARMS). ERMS is associated with an 11p15.5 loss of heterozygosity (LOH) and may be confused with nonmyogenic, non-RMS soft tissue sarcomas. ARMS expresses the product of a genomic translocation that fuses FOXO1 (FKHR) with either PAX3 or PAX7 (P-F); however, at least 25% of cases lack these translocations. Here, we describe a genomic-based classification scheme that is derived from the combined gene expression profiling and LOH analysis of 160 cases of RMS and non-RMS soft tissue sarcomas that is at variance with conventional histopathological schemes. We found that gene expression profiles and patterns of LOH of ARMS cases lacking P-F translocations are indistinguishable from conventional ERMS cases. A subset of tumors that has been histologically classified as RMS lack myogenic gene expression. However, classification based on gene expression is possible using as few as five genes with an estimated error rate of less than 5%. Using immunohistochemistry, we characterized two markers, HMGA2 and TFAP2ss, which facilitate the differential diagnoses of ERMS and P-F RMS, respectively, using clinical material. These objectively derived molecular classes are based solely on genomic analysis at the time of diagnosis and are highly reproducible. Adoption of these molecular criteria may offer a more clinically relevant diagnostic scheme, thus potentially improving patient management and therapeutic RMS outcomes.

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.