Elizabeth J. Perlman

ALK1 and p80 Expression and Chromosomal Rearrangements Involving 2p23 in Inflammatory Myofibroblastic Tumor

Background: Inflammatory myofibroblastic tumor (IMT) is an uncommon tumor of extrapulmonary and pulmonary tissues with an unpredictable clinical course, occasional recurrences, and rare malignant transformation. Clonal abnormalities with rearrangements of chromosome of 2p23 and the ALK gene have been reported in a few cases. The purpose of this study is to investigate whether these are consistent abnormalities among IMTs or represent a distinct subset. Design: Formalin-fixed, paraffin-embedded archival tissue sections from 47 IMTs in 40 patients were immunostained with monoclonal antibodies against ALK and p80. Fluorescence in situ hybridization for ALK rearrangements was done on 22 IMTs from 19 patients. Findings were correlated with clinical features and outcome. Results: ALK positivity was observed in 17 of 47 IMTs (36%) and p80 positivity in 16 of 47 IMTs (34%). Fluorescence in situ hybridization showed ALK rearrangements in nine cases (47%), aneuploidy in three cases (16%), and no rearrangement in seven cases (37%). IMTs with ALK abnormalities by immunohistochemistry and/or fluorescence in situ hybridization originated in the abdomen/pelvis/retroperitoneum, chest, and extremities. The mean age was 6.6 years, with a male/female ratio of 1.3. 64% of patients had no evidence of disease at last follow-up, 45% had one or more recurrences, and 18% displayed histologic evidence of malignant transformation. The IMTs without ALK abnormalities occurred in older children, were more frequent in females, and had fewer recurrences. However, in this group of 40 patients, the differences between the groups with and without ALK abnormalities did not have statistical significance. Aneuploidy without ALK abnormalities was associated with malignant transformation in three of five cases. Conclusions: Abnormalities of ALK and p80 and evidence of chromosomal rearrangements of 2p23 occur in a significant proportion of IMTs. These changes are most frequent in abdominal and pulmonary IMTs in the first decade of life and are associated with a higher frequency of recurrence. These findings confirm the neoplastic nature of a subset IMT with ALK abnormalities and suggest that aneuploid IMT is a subset with more aggressive clinical behavior.

Immunohistochemical analysis of hSNF5/INI1 distinguishes renal and extra-renal malignant rhabdoid tumors from other pediatric soft tissue tumors.

Malignant rhabdoid tumor (MRT) is a highly aggressive neoplasm that occasionally demonstrates phenotypic overlap with other soft tissue malignancies. Molecular genetic analysis of MRT frequently demonstrates deletion or mutation of the hSNF5/INI1 gene, with corresponding reduced expression at the protein level. INI1 immunohistochemistry was performed to determine the utility of this method in assessing loss of INI1 expression in rhabdoid tumors. Twenty-seven MRTs with molecular analysis (19 renal, 8 extra-renal) were evaluated. Seventeen additional MRT (10 renal, 7 extra-renal) without INI1 molecular analysis were also analyzed. Loss of INI1 expression was observed in the tumor cells in all 44 cases. To determine the specificity of this assay, a variety of 45 pediatric soft tissue tumors, some of which occasionally display rhabdoid differentiation, were investigated. These included Ewing’s sarcoma, Wilms’ tumor, desmoplastic small round cell tumor, clear cell sarcoma, congenital mesoblastic nephroma, synovial sarcoma, undifferentiated sarcoma, rhabdomyosarcoma, and epithelioid sarcoma. Positive nuclear staining was found in all nonrhabdoid tumors examined. Of interest, synovial and epithelioid sarcomas exhibited variable and/or focal staining. INI1 antibody immunohistochemistry is useful in confirming the histologic diagnosis of renal or extra-renal rhabdoid tumor, especially for cases with indeterminate histologic features, equivocal immunophenotypic profiles, or uninformative molecular studies.

Clear cell sarcoma of the kidney : A review of 351 cases from the National Wilms tumor Study Group pathology center

We reviewed 351 cases of clear cell sarcoma of the kidney (CCSK), including 182 cases entered on National Wilms Tumor Study Group (NWTSG) trials 1-4 for which clinical follow-up information was available. Tumors were restaged using NWTS 5 criteria. Mean age at diagnosis in the NWTS group was 36 months with a range of 2 months to 14 years. The male to female ratio was 2:1. Typical gross features included large size (mean diameter 11.3 cm), a mucoid texture, foci of necrosis, and prominent cyst formation. Nine major histologic patterns were identified (classic, myxoid, sclerosing, cellular, epithelioid, palisading, spindle, storiform, and anaplastic); virtually all tumors contained multiple patterns that blended with one another. Immunohistochemical stains were performed on 45 cases; only vimentin was consistently immunoreactive. Consistently negative results with other antibodies helped exclude other tumors in the differential diagnosis; all CCSKs were cytokeratin-negative, including epithelioid tumors that mimicked Wilms tumor, and MIC2-negative, including cellular tumors that mimicked primitive neuroectodermal tumor. The p53 gene product was rarely overexpressed in non-anaplastic CCSKs, but strikingly overexpressed in two of three anaplastic CCSKs. Overall survival was 69%. Multivariate analysis revealed four independent prognostic factors for survival: treatment with doxorubicin, stage, age at diagnosis, and tumor necrosis. Of note, stage 1 patients had a remarkable 98% survival rate. No other histologic or clinical variable independently correlated with survival.

Dose-Intensified Compared With Standard Chemotherapy for Nonmetastatic Ewing Sarcoma Family of Tumors: A Children's Oncology Group Study

PURPOSE The Ewing sarcoma family of tumors (ESFT) is a group of malignant tumors of soft tissue and bone sharing a chromosomal translocation affecting the EWS locus. The Intergroup INT-0091 demonstrated the superiority of a regimen of vincristine, cyclophosphamide, doxorubicin (VDC), and dactinomycin alternating with ifosfamide and etoposide (IE) over VDC for patients with nonmetastatic ESFT of bone. The goal of this study was to determine whether a dose-intensified regimen of VDC alternating with IE would further improve the outcome for patients with nonmetastatic ESFT of bone or soft tissue. METHODS Patients with previously untreated, nonmetastatic ESFT of bone or soft tissue were eligible. They were randomly assigned to receive standard doses of VDC/IE over 48 weeks or a dose-intensified regimen of VDC/IE over 30 weeks. RESULTS Four hundred seventy-eight patients met eligibility requirements: 231 patients received the standard regimen; 247 patients received the intensified regimen. The 5-year event-free survival (EFS) and overall survival rates for all eligible patients were 71.1% (95% CI, 67.7% to 75.0%) and 78.6% (95% CI, 74.6% to 82.1%), respectively. There was no significant difference (P = .57) in EFS between patients treated with the standard (5-year EFS, 72.1%; 95% CI, 65.8% to 77.5%) or intensified regimen (5-year EFS, 70.1%; 63.9% to 75%). Patients with soft tissue tumors accounted for 20% of the study population; there was no difference in outcome between patients with soft tissue and bone primary sites. CONCLUSION Dose escalation of alkylating agents as tested in this trial did not improve the outcome for patients with nonmetastatic ESFT of bone or soft tissue.

Renal medullary carcinoma: clinical, pathologic, immunohistochemical, and genetic analysis with pathogenetic implications

OBJECTIVES To investigate the pathologic, clinical, and genetic features of renal medullary carcinomas (RMCs) in search of clues to their pathogenesis. METHODS We analyzed 40 RMCs for clinical features, for immunohistochemical expression using a panel of markers, and for genetic changes using comparative genomic hybridization. RESULTS Patients presented at 5 to 32 years of age, and 82% were African American. All patients tested had sickle cell trait or disease. Seven patients presented with suspected renal abscess or urinary track infection without a clinically recognizable mass. Of the 15 tumors able to be analyzed, all were positive for epithelial markers CAM 5.2 and epithelial membrane antigen. All were negative for high-molecular-weight cytokeratin 34betaE12. Cytokeratins 7 and 20 and carcinoembryonic antigen were heterogeneous and variable. Ulex was focally positive in a minority of cases. Eight of 12 tumors showed significant positivity for TP53 protein (greater than 25% nuclear positivity). All tumor tested (n = 8) were strongly positive for vascular endothelial growth factor and hypoxia inducible factor. Of nine tumors analyzed for genetic gains and losses using comparative genomic hybridization, eight showed no changes and one showed loss of chromosome 22. Survival ranged from 2 weeks to 15 months (mean 4 months). CONCLUSIONS These findings suggest that RMC is clinically and pathologically distinct from collecting duct carcinoma. The hypothesis that chronic medullary hypoxia secondary to hemoglobinopathy may be involved in the pathogenesis of RMC is suggested by strong vascular endothelial growth factor and hypoxia inducible factor expression and positivity for TP53.

A Distinctive Pediatric Renal Neoplasm Characterized by Epithelioid Morphology, Basement Membrane Production, Focal HMB45 Immunoreactivity, and t(6;11)(p21.1;q12) Chromosome Translocation

We report two cases of a hitherto undescribed pediatric renal neoplasm that is distinctive at the morphological, immunohistochemical, ultrastructural, and cytogenetic levels. On light microscopy, the tumors are composed of nests of polygonal, clear to eosinophilic cells associated with a subpopulation of smaller cells that surround hyaline material. Despite their epithelioid morphology, these tumors do not label immunohistochemically for epithelial markers but instead label focally for melanocytic markers HMB45 and Melan A. The hyaline material is positive with periodic acid-Schiff and methenamine-silver histochemical stains, and labels immunohistochemically for type 4 collagen. Ultrastructural examination confirms that it represents basement membrane material. Cytogenetic analysis reveals the identical t(6;11)(p21.1;q12) chromosome translocation as the sole abnormality in these two tumors, confirming their identity and distinctive nature.

Myogenin is a specific marker for rhabdomyosarcoma: an immunohistochemical study in paraffin-embedded tissues.

Myogenin belongs to a group of myogenic regulatory proteins whose expression determines commitment and differentiation of primitive mesenchymal cells into skeletal muscle. The expression of myogenin has been demonstrated to be extremely specific for rhabdomyoblastic differentiation, which makes it a useful marker in the differential diagnosis of rhabdomyosarcomas (RMS) from other malignant small round cell tumors of childhood. Commercially available antibodies capable of detecting myogenin in routinely processed formalin-fixed paraffin-embedded (FFPE) tissue are now available. In this study, we evaluated myogenin expression using the monoclonal myf-4 antibody (Novocastra Labs) on FFPE in a large number of pediatric tumors in order to define the clinical utility of this marker. A total of 119 tumors were studied. These included 48 alveolar RMS (ARMS), 20 embryonal RMS (ERMS), one spindle cell RMS, 16 Ewings sarcomas (ES), six nephroblastomas, two ectomesenchymomas, seven precursor hematopoietic neoplasms, five olfactory neuroblastomas, three neuroblastomas, six desmoplastic small round cell tumors, and five rhabdoid tumors. Distinct nuclear staining for myogenin was noted in all 69 RMS. Notably, the number of positive tumor cells differed between the ARMS and ERMS. In ARMS, the majority of tumor cells (75 to 100%) were positive, in contrast to ERMS, in which the positivity ranged from rare + to 25% in all but three tumors. Additionally, myogenin positivity was seen in two of two ectomesenchymomas and in two nephroblastomas with myogenous differentiation. All other tumors were clearly negative. Our results indicate that staining for myogenin is an extremely reliable and specific marker for rhabdomyoblastic differentiation. It gives consistent and easily interpretable results in routinely fixed tissues.

Treatment of Metastatic Ewing's Sarcoma or Primitive Neuroectodermal Tumor of Bone: Evaluation of Combination Ifosfamide and Etoposide—A Children's Cancer Group and Pediatric Oncology Group Study

PURPOSE One hundred twenty patients with metastatic Ewings sarcoma or primitive neuroectodermal tumor (PNET) of bone were entered onto a randomized trial evaluating whether the addition of ifosfamide and etoposide to vincristine, doxorubicin, cyclophosphamide, and dactinomycin improved outcomes. METHODS Thirty-two patients had metastases to lungs only, 12 patients had metastases to bone marrow or bones only, 64 patients had metastases in multiple sites, and five patients had metastases in other sites; seven patients could not be assessed precisely. Treatment comprised 9 weeks of chemotherapy before local control and 42 weeks of chemotherapy; thereafter, regimen A consisted of vincristine 2 mg/m(2), cyclophosphamide 1,200 mg/m(2), and either doxorubicin 75 mg/m(2) or dactinomycin 1.25 mg/m(2). Regimen B consisted of regimen A alternating every 3 weeks with ifosfamide 1,800 mg/m(2)/d for 5 days and etoposide 100 mg/m(2)/d for 5 days. RESULTS Patients treated on regimen B did not have significantly better survival than those treated on regimen A. The event-free survival (EFS) and survival (S) at 8 years were 20% (SE, 5%) and 32% (SE, 6%), respectively, for those treated on regimen A and 20% (SE, 6%) and 29% (SE, 6%), respectively, for those treated on regimen B. Patients who had only lung metastases had EFS and S of 32% (SE, 8%) and 41% (SE, 9%), respectively, at 8 years. There were six toxic deaths (5%), four from cardiac toxicity and two from sepsis (four treated on regimen B and two treated on regimen A). Two had second malignant neoplasms. CONCLUSION Adding ifosfamide and etoposide to standard therapy does not improve outcomes of patients with Ewings sarcoma or PNET of bone with metastases at diagnosis.

Ewing's sarcoma—Routine diagnostic utilization of MIC2 analysis: A pediatric oncology group/children's cancer group intergroup study

Ewings sarcoma and peripheral neuroectodermal tumor (PNET) are small blue cell tumors with no reliable positive diagnostic markers. However, Ewings sarcoma and PNET recently have been shown to strongly express an antigen determined by the MIC2 gene, whereas other blue cell tumors of childhood for the most part do not. MIC2 analysis therefore offers a distinctive addition to the panel of immunohistochemical stains used to differentiate among small blue cell tumors of childhood, since it represents the first positive marker for Ewings sarcoma and PNET. This study addresses the reliability of MIC2 analysis using the monoclonal antibody 12E7 on tumors registered in the current Intergroup Ewings Sarcoma protocol. Of 244 tumors, 221 (91%) showed a diffuse strong membranous pattern. The antibody appears to withstand all the fixation variables inherent in a multi-institutional study. We conclude that MIC2 expression is highly reliable as a positive marker for the Ewings sarcoma/PNET family of tumors when the results are interpreted in the total context with clinical and pathologic parameters.

Comparative genomic hybridization detects an increased number of chromosomal alterations in large cell/anaplastic medulloblastomas.

We correlate chromosomal changes in medulloblastomas with histologic subtype, reporting the analysis of 33 medulloblastoma specimens by comparative genomic hybridization, and a subset by fluorescence in situ hybridization. Of the 33 tumors, 5 were desmoplastic/nodular, 10 were histologically classic, and 18 were large cell/anaplastic. Chromosomal gains and losses were more common in anaplastic medulloblastomas than in non‐anaplastic ones. We identified 4 medulloblastomas with c‐myc amplification and 5 medulloblastomas with N‐myc amplification; all 9 were of the large cell/anaplastic subtype. Additional regions with high level gains included 2q14‐22, 3p23, 5p14‐pter, 8q24, 9p22‐23, 10p12‐pter, 12q24, 12p11‐12, 17p11‐12, and Xp11. The majority of these high level gains occurred in anaplastic cases. We also found loss of chromosome 17p in 7 large cell/anaplastic cases but no non‐anaplastic medulloblastomas. Finally, we detected a significantly increased overall number of chromosomal alterations in large cell/anaplastic medulloblastomas (6.8/case) compared to non‐anaplastic ones (3.3/case). These findings support an association between myc oncogene amplification, 17p loss, and large cell/anaplastic histology.