Gabriele Amann

Angiosarcomas Express Mixed Endothelial Phenotypes of Blood and Lymphatic Capillaries: Podoplanin as a Specific Marker for Lymphatic Endothelium

Angiosarcomas apparently derive from blood vessel endothelial cells; however, occasionally their histological features suggest mixed origin from blood and lymphatic endothelia. In the absence of specific positive markers for lymphatic endothelia the precise distinction between these components has not been possible. Here we provide evidence by light and electron microscopic immunohistochemistry that podoplanin, a approximately 38-kd membrane glycoprotein of podocytes, is specifically expressed in the endothelium of lymphatic capillaries, but not in the blood vasculature. In normal skin and kidney, podoplanin colocalized with vascular endothelial growth factor receptor-3, the only other lymphatic marker presently available. Complementary immunostaining of blood vessels was obtained with established endothelial markers (CD31, CD34, factor VIII-related antigen, and Ulex europaeus I lectin) as well as podocalyxin, another podocytic protein that is also localized in endothelia of blood vessels. Podoplanin specifically immunolabeled endothelia of benign tumorous lesions of undisputed lymphatic origin (lymphangiomas, hygromas) and was detected there as a 38-kd protein by immunoblotting. As paradigms of malignant vascular tumors, poorly differentiated (G3) common angiosarcomas (n = 8), epitheloid angiosarcomas (n = 3), and intestinal Kaposis sarcomas (n = 5) were examined for their podoplanin content in relation to conventional endothelial markers. The relative number of tumor cells expressing podoplanin was estimated and, although the number of cases in this preliminary study was limited to 16, an apparent spectrum of podoplanin expression emerged that can be divided into a low-expression group in which 0-10% of tumor cells contained podoplanin, a moderate-expression group with 30-60% and a high-expression group with 70-100%. Ten of eleven angiosarcomas and all Kaposis sarcomas showed mixed expression of both lymphatic and blood vascular endothelial phenotypes. By double labeling, most podoplanin-positive tumor cells coexpressed endothelial markers of blood vessels, whereas few tumor cells were positive for individual markers only. From these results we conclude that (1) podoplanin is a selective marker of lymphatic endothelium; (2) G3 angiosarcomas display a quantitative spectrum of podoplanin-expressing tumor cells; (3) in most angiosarcomas, a varying subset of tumor cells coexpresses podoplanin and endothelial markers of blood vessels; and (4) all endothelial cells of Kaposis sarcomas expressed the lymphatic marker podoplanin.

Role of Ploidy, Chromosome 1p, and Schwann Cells in the Maturation of Neuroblastoma

BACKGROUND Neuroblastoma is a heterogeneous disease, with manifestations ranging from spontaneous regression to lethal spread. Sometimes the tumor spontaneously differentiates toward a benign ganglioneuroma (maturing neuroblastoma). The prognosis is frequently related to ploidy, deletions in the short arm of chromosome 1, and amplifications of the N-myc oncogene. Maturing neuroblastomas consist of both neuronal cells and Schwann cells. We investigated the genetic composition of both cell types in maturing neuroblastomas, to determine the relation between genetic abnormalities and maturation. METHODS We studied 20 maturing and mature neuroblastomas by in situ hybridization to count the chromosomes and evaluate possible deletions in the short arm of chromosome 1 in neuronal and Schwann cells. The DNA content of the cells was measured by flow cytometry. RESULTS Neuroblastic and ganglionic cells showed aberrations in the number of chromosomes. In situ hybridization and flow cytometry demonstrated near-trip-loidy in 18 of 19 tumors and pentaploidy in the remaining tumor. The Schwann cells in all 20 neuroblastomas contained normal numbers of chromosomes. In 18 tumors studied, there were no chromosome 1 deletions in either type of cell. CONCLUSIONS The Schwann cells in maturing neuroblastomas differ genetically from the neuronal cells. The normal number of chromosomes in Schwann cells and the abnormal number in neuroblastic ganglionic cells suggests that Schwann cells are a reactive population of normal cells that invade the neuroblastoma. Near-trip-loidy of neuroblastoma cells and intact chromosome 1 are presumably genetic prerequisites for spontaneous organoid maturation, because we found no diploidy or chromosome 1 depletions in the neuronal cells of spontaneously maturing neuroblastomas.

Quality Assessment of Genetic Markers Used for Therapy Stratification

PURPOSE Therapy stratification based on genetic markers is becoming increasingly important, which makes commitment to the highest possible reliability of the involved markers mandatory. In neuroblastic tumors, amplification of the MYCN gene is an unequivocal marker that indicates aggressive tumor behavior and is consequently used for therapy stratification. To guarantee reliable and standardized quality of genetic features, a quality-assessment study was initiated by the European Neuroblastoma Quality Assessment (ENQUA; connected to International Society of Pediatric Oncology) Group. MATERIALS AND METHODS One hundred thirty-seven coded specimens from 17 tumors were analyzed in 11 European national/regional reference laboratories using molecular techniques, in situ hybridization, and flow and image cytometry. Tumor samples with divergent results were re-evaluated. RESULTS Three hundred fifty-two investigations were performed, which resulted in 23 divergent findings, 17 of which were judged as errors after re-evaluation. MYCN analyses determined by Southern blot and in situ hybridization led to 3.7% and 4% of errors, respectively. Tumor cell content was not indicated in 32% of the samples, and 11% of seemingly correct MYCN results were based on the investigation of normal cells (eg, Schwann cells). Thirty-eight investigations were considered nonassessable. CONCLUSION This study demonstrated the importance of revealing the difficulties and limitations for each technique and problems in interpreting results, which are crucial for therapeutic decisions. Moreover, it led to the formulation of guidelines that are applicable to all kinds of tumors and that contain the standardization of techniques, including the exact determination of the tumor cell content. Finally, the group has developed a common terminology for molecular-genetic results.

Variability of EWS chimaeric transcripts in Ewing tumours: a comparison of clinical and molecular data.

Ewing tumours (ET), including Ewings sarcoma and peripheral primitive neuroectodermal tumour, are well characterised at the molecular level by a unique chromosomal rearrangement which fuses the EWS gene to one of two closely related ETS proto-oncogenes, FLI-1 or ERG. Expression of the resulting chimaeric transcripts can be readily detected by reversed transcriptase polymerase chain reaction (RT-PCR). This approach led to the identification of a number of different exon combinations at the junction site of coding sequences. The physiological consequences of the observed variability in the hinge region of EWS chimaeric proteins are not known. We have analysed tumour-derived material from 30 ET patients with well-documented clinical course (18 with localised and 12 with metastatic disease at diagnosis) for the presence of EWS/FLI-1 or EWS/ERG RNA. Karyotypes were obtained in 21 out of 27 cases and analysed by routine cytogenetics. A chromosome 22 rearrangement was demonstrated in 18 cases (67%). In contrast, RT-PCR revealed the presence of chimaeric transcripts in 28 tumours (93%), with fusions of EWS exon 7 to FLI-1 exons 6 (19/28), 5 (4/28) and 7 (1/28). In addition, EWS/FLI-1 exon combinations 10/5 and 9/4 were observed in one case each. In the last tumour, the presence of at least four additional splicing variants corresponding to fusion of EWS exon 7 to FLI-1 exons 4, 6, 8 and 9 was demonstrated. Two tumours expressed EWS/ERG fusion transcripts involving EWS exon 7 and ERG exon 6. In this study, EWS/FLI-1 exon combinations 7/6 (type I) predominated over 7/5 (type II) in localised ET (14 versus 1) and were more abundant in tumours affecting the long bones (9 versus 0), whereas in central axis tumours and metastatic disease there was only little difference in the frequency of the two types. So far, no correlations between different chimaeric EWS transcripts and any other clinical parameters have been identified.

Predictive potential of testing for bone marrow involvement in Ewing tumor patients by RT-PCR : A preliminary evaluation

EWS/ets‐oncogene fusion transcripts can be detected in at least 98% of Ewing tumors [(ET) Ewing sarcoma and peripheral primitive neuroectodermal tumor] by reverse transcriptase‐polymerase chain reaction (RT‐PCR), thus confirming the histopathologic diagnosis. To detect minimal amounts of tumor cells in the bone marrow (BM), we used an RT‐PCR assay with a high sensitivity, revealing one tumor cell in a background of 106 normal cells. We examined BM samples from 35 newly diagnosed ET patients (23 with localized and 12 with metastatic disease). At diagnosis, tumor cells in the BM were detected in 7/23 patients with localized disease (30%). Fifty percent of patients with isolated lung metastasis were RT‐PCR positive (3/6), whereas 6/6 patients with bone metastases showed positive signals (100%). All patients with initial PCR positivity in the BM became negative during treatment. After a median follow‐up of 30 months, relapses were observed in both groups of patients with localized disease (3/7 RT‐PCR positive and 2/16 RT‐PCR negative). The only recurrence in the group with isolated lung metastases occurred as progressive lung disease in 1 of the 2 RT‐PCR‐negative patients, whereas among the 6 patients with bone metastases 2 remain in complete remission. So far, RT‐PCR screening for BM involvement did not allow prediction of early relapse in ET. To assess better the significance of this test in the evaluation of long‐term prognosis and in monitoring the effectiveness of systemic therapy, long observation periods are warranted before it becomes a tool for treatment stratification. Int. J. Cancer (Pred. Oncol.) 79:56–60, 1998.

Intensified Adjuvant IFADIC Chemotherapy for Adult Soft Tissue Sarcoma: A Prospective Randomized Feasibility Trial

Purpose. The present prospective randomized adjuvant trial was carried out to compare the toxicity, feasibility and efficacy of augmented chemotherapy added to hyperfractionated accelerated radiotherapy after wide or marginal resection of grade 2 and grade 3 soft tissue sarcoma (STS).Patients and methods. Fifty-nine patients underwent primary surgery by wide or marginal excision and were subsequently randomized to receive radiotherapy alone or under the addition of six courses of ifosfamide (1500 mg/m(2) , days 1-4), dacarbazine (DTIC) (200 mg/m(2) , days 1-4) and doxorubicin (25 mg/m(2) , days 1-2) administered in 14-day-intervals supported by granulocyte-colony stimulating factor (30 x 10(6) IU/day, s.c.) on days 5-13. According to the randomization protocol, 28 patients received radiotherapy only, whereas 31 patients were treated with additional chemotherapy.Results. The relative ifosfamide-doxorubicin-DTIC (IFADIC) dose intensity achieved was 93%. After a mean observation period of 41+/-19.7 months (range, 8.1-84 months), 16 patients (57%) in the control group versus 24 patients (77%) in the chemotherapy group were free of disease (p>0.05).Within the control group, tumor relapses occurred in 12 patients (43%;six patients with distant metastases, two with local relapse, four with both) versus seven patients (23%; five patients with distant metastases, one with local recurrence, one with both) from the chemotherapy group. Relapse-free survival (RFS) (p=0.1), time to local failure (TLF) (p=0.09), time to distant failure (TDF) (p=0.17) as well as overall survival (OS) (p=0.4) did not differ significantly between the two treatment groups. Treatment-related toxicity was generally mild in both treatment arms.Conclusion. We conclude that the safety profile of intensified IFADIC added to radiotherapy was manageable and tolerable in the current setting. Inclusion of intensified IFADIC was not translated into a significant benefit concerning OS, RFS, TLF andTDF as compared with radiotherapy only, although a potential benefit of chemotherapy for grade 3 STS patients needs to be validated in prospective randomized trials including larger patient numbers.

Intratumoural heterogeneity of 1p deletions and MYCN amplification in neuroblastomas.

BACKGROUND At least three genetic hallmarks identify aggressive tumour behaviour in neuroblastomas; amplification of the oncogene MYCN; deletion (loss of heterozygosity [LOH]) at the short arm of chromosome 1 (del1p36), seen in approximately 28% of the cases; and di-tetraploidy. The MYCN oncogene is amplified in approximately 23% of all neuroblastomas and becomes important for the stratification of therapy in localised and 4s tumours. Up to now, it has been believed that the genetic constellation of neuroblastic tumours is stable and does not alter during tumour evolution or during tumour progression. PROCEDURE Using fluorescence in situ hybridisation techniques (FISH) to investigate different tumour areas on touch preparations and histological sections, we show that genetic heterogeneity can be detected in neuroblastomas, especially in tumours detected by urinary mass screening. CONCLUSION The identification of such cell clones is important, because the MYCN amplification and/or the deletion at 1p36 appear to be responsible for aggressive local growth and development of metastases.

Treatment of extra-abdominal desmoid tumors with interferon-alpha with or without tretinoin.

Surgery is the main treatment for extra‐abdominal desmoid tumors, but the results of further management remain uncertain. Therefore, a retrospective analysis was undertaken to evaluate the toxicity and efficacy of treatment with interferon‐alpha (IFN‐α) ± tretinoin in this setting.

Prognostic significance of DNA di-tetraploidy in neuroblastoma

BACKGROUND Identification of biological factors may provide tools to discriminate poor risk neuroblastoma patients of diagnosis, to ultimately offer risk adapted treatment intensity. PROCEDURES Tumour cell DNA content, MYCN amplification (NMA), deletion of the short arm of chromosome 1 (del 1p) as well as three serological markers were assessed in 179 children with neuroblastoma. RESULTS Localised regional disease (stage 1 to 3) was diagnosed in 98 patients, and disseminated disease in 81 patients (65 with stage 4, 16 with stage 4s). Median age at diagnosis was 12 months and the median observation time 4 years. Sixty-seven of 179 patients had near di-tetraploid tumours (37%), with a significantly worse prognosis of 44% overall survival at 4 years in comparison with 88% in near triploid tumours (P < .001). The near di-tetraploid group showed a significant correlation with additional adverse biological factors (NMA, del 1p: P < 0.001), age over 1 year (P< 0.001), clinical stage 4 (P< 0.001), elevated ferritin (P = 0.023), and elevated LDH (P< 0.001). Multivariate analysis based on the overall (OS) and event free survival (EFS) estimations revealed that near di-tetraploidy was the most powerful biological factor, with a P-value of <0.001 for EFS and OS, followed by NMA (P = 0.015) for OS and del 1p (P= 0.047) for EFS. CONCLUSIONS This analysis underlines the important influence of near di-tetraploidy on prognosis, and suggests that more efforts should be undertaken to implement this factor in future studies.

Docetaxel as rescue medication in anthracycline- and ifosfamide-resistant locally advanced or metastatic soft tissue sarcoma: Results of a phase II trial

BACKGROUND Metastatic soft tissue sarcoma not amenable to curative surgery has a dismal prognosis. Aggressive treatment with anthracyclines and ifosfamide represents the current therapeutic mainstay in these patients, most of whom succumb to relapses. Thus, the efficacy of subsequent therapeutic approaches has to be weighed against toxicity caused by palliative treatment. PATIENTS AND METHODS Patients with locally advanced or metastatic soft tissue sarcoma refractory to treatment with anthracyclines and ifosfamide were enrolled into the present phase II study. Patients were assigned to receive docetaxel at 100 mg/m2 every three weeks. In case of severe toxicity, patients were switched to a weekly schedule of docetaxel (40 mg/m2). RESULTS A total of 106 cycles (80% at the scheduled 100 mg/m2 dose level) were administered in 27 patients. Partial response was observed in 4 (15%) patients and 4 (15%) patients experienced disease stabilization. Median progression free survival and overall survival were 2.4 (range: 0.9-23.9) and 7.7 (range: 1.0-44.3) months, respectively. Upon renewed progression, three patients initially responsive to treatment with docetaxel were successfully reinduced by treatment with docetaxel. The safety profile of docetaxel was tolerable and the administration mostly manageable on an outpatient basis. CONCLUSIONS Our results suggest that docetaxel represents an efficacious and tolerable treatment in a minority of patients refractory to standard treatment. There is a need for better identification of patients most likely to benefit from salvage treatment with docetaxel.