Improved Outcome in Local Ewing Sarcoma With an Intensified Pilot Treatment Protocol SCMCIE 94.

This study evaluated the effect of an intensified pilot protocol, SCMCIE 94, on the outcome of Ewing sarcoma (EWS). The cohort included 121 patients with local or metastatic EWS treated at a tertiary pediatric medical center with the SCMCIE 94 (protocol 3, 1994 to 2011) or an earlier protocol (protocol 2, 1988 to 1994; protocol 1, 1985 to 1988). All protocols included 4 to 6 courses of chemotherapy, radiation, and surgery. Clinical data were collected retrospectively by chart review. Survival rates for protocol 3 were as follows: all patients-5-year event-free survival (EFS): 52.5%±5.6%, 10-year EFS: 49.3%±5.8%, 5-year overall survival (OS): 68.8%±5.3%, and 10-year OS: 51.1%±6.3%; patients with localized disease (any site)-5-year EFS: 63.5%±6.0% and 5-year OS: 77.2%±5.3%; patients with localized extremity disease-5-year EFS: 78.95%±8.3%, 10-year EFS: 68.6%±10.0%, 5-year OS: 90.7%±6.2%, and 10-year OS: 71.1%±11.2%. Protocol 3 was associated with an increase in 10-year EFS of 16% overall and 33% in patients with localized extremity disease compared with protocols 1+2, and a significant improvement in 5-year EFS and OS in patients with any localized disease (P=0.001). No survival benefit was found for metastatic disease. On multivariate analysis, protocol and metastatic disease were significantly independent prognostic factors. The intensified SCMCIE 94 protocol seems to increase survival in patients with localized but not metastatic EWS.

Visual diagnosis: an 11-year-old girl who has left leg pain.

Unicameral bone cysts (UBCs) in children usually are asymptomatic. Most UBCs are discovered when a radiograph is performed on a child who has had accidental trauma to a limb. Symptomatic cysts typically present with pain, often the result of pathologic fracture through a large cyst or occult stress fracture within the thinned cortex around the cyst. Simple radiography is the best method for detecting such cysts, which typically are located within the long bone (femur, tibia, fibula, humerus), but can appear elsewhere. Cysts typically appear in the proximal metaphysis, but some involve the epiphysis and growth plate, thereby affecting bone growth. If clinically necessary to confirm the diagnosis, computed tomography or magnetic resonance imaging can delineate the cyst better or demonstrate an occult fracture. For the asymptomatic UBC, close follow-up is the recommended course of action. However, surgical intervention by corticosteroid or autogenous bone marrow injection or open curettage with bone grafting is recommended if the cyst is symptomatic, carries an increased risk for pathologic fracture (weight-bearing bone or dominant arm of a throwing athlete), or shows signs of an impending pathologic fracture. Clinical and radiographic follow-up is recommended after surgical intervention, because UBC recurrence after initial surgery is reported to occur in 18% to 88% of patients.

Pre-clinical and clinical significance of heparanase in Ewing's sarcoma.

Heparanase is an endoglycosidase that specifically cleaves heparan sulphate side chains of heparan sulphate proteoglycans, activity that is strongly implicated in cell migration and invasion associated with tumour metastasis, angiogenesis and inflammation. Heparanase up-regulation was documented in an increasing number of human carcinomas, correlating with reduced post-operative survival rate and enhanced tumour angiogenesis. Expression and significance of heparanase in human sarcomas has not been so far reported. Here, we applied the Ewing's sarcoma cell line TC71 and demonstrated a potent inhibition of cell invasion in vitro and tumour xenograft growth in vivo upon treatment with a specific inhibitor of heparanase enzymatic activity (compound SST0001, non-anticoagulant N-acetylated, glycol split heparin). Next, we examined heparanase expression and cellular localization by immunostaining of a cohort of 69 patients diagnosed with Ewing's sarcoma. Heparanase staining was noted in all patients. Notably, heparanase staining intensity correlated with increased tumour size (P = 0.04) and with patients' age (P = 0.03), two prognostic factors associated with a worse outcome. Our study indicates that heparanase expression is induced in Ewing's sarcoma and associates with poor prognosis. Moreover, it encourages the inclusion of heparanase inhibitors (i.e. SST0001) in newly developed therapeutic modalities directed against Ewing's sarcoma and likely other malignancies.

Expression and significance of EGFR in malignant peripheral nerve sheath tumor.

Malignant peripheral nerve sheath tumor (MPNST) is an aggressive sarcoma. Epidermal growth factor receptor (EGFR) may play a putative role in its pathogenesis, and be targeted for therapeutic purposes. The study was aimed at investigating the expression and prognostic influence of EGFR in MPNST. Primary and metastatic MPNSTs were immunostained with antibodies to EGFR. The total EGFR expression (membranous and cytoplasmic) was analyzed by morphometry, grade of positivity and the intensity (score 0-3). An EGFR composite score (range 0-300) was calculated by multiplying the intensity by the grade. A composite score >10 was considered as EGFR overexpression. Score was correlated with clinical behavior. Forty-three percentage of 46 patients with MPNST overexpressed EGFR in the primary tumor, and had a higher prevalence of advanced-stage tumors (>or=IIc, 46% vs. 80%, P = 0.011). Patients without overexpression had a higher prevalence of tumors with a low mitotic rate (31% vs. 0%, P = 0.049). Neurofibromatosis was more prevalent in patients with EGFR overexpression (75% vs. 42%, P = 0.007). Five year disease free survival (mean 30.1 vs. 17.4 months, P = 0.048), time to progression (mean 9.2 vs. 5.2 months, P = 0.005) and 5 year survival (52% vs. 25%, P = 0.041, mean 54 vs. 43 months) were significantly higher among patients without overexpression. EGFR appeared to play a role in MPNST progression. EGFR overexpression was correlated with worse prognostic variables and course. Clinical trials of targeting EGFR in MPNST are warranted.

Aberrant methylation and reduced expression of RASSF1A in Ewing sarcoma.

BACKGROUND: Ewing sarcoma (ES) is the second most common solid bone and soft tissue malignancy in children and young adults with low cure rates indicating the need to identify further prognostic markers. The importance of methylation in the inactivation of key tumor suppressor genes including RASSF1A has begun to be appreciated in context of cancer development, prognosis and therapy. However there is lack of similar broad based studies in ES. The objective of this study was to analyze RASSF1A methylation and assess its clinical significance in ES. PROCEDURE: The methylation of RASSF1A was determined 31 ES tumor samples and 4 ES cell lines. ES cell lines were also treated with demethylating agent 5-aza-2'-deoxycytidine to ascertain its effect on methylation. RASSF1A expression was studied in 12 ES tumors. The association between RASSF1A methylation, clinical parameters and outcome was also analyzed. RESULTS: Methylation of RASSF1A was observed in 21/31 (68%) tumors and in 3/4 ES cell lines. A significant correlation of methylation to reduced expression of RASSF1A was observed in 12 ES tumors analyzed (P = 0.0013) and in all cell lines. ES patients with methylated RASSF1A had worse prognosis compared to the unmethylated group (P = 0.049). Treatment with 5-aza-2'-deoxycytidine resulted in the re-expression of the unmethylated form of RASSF1A in two ES cell lines. CONCLUSION: RASSF1A is frequently methylated in ES.

Unusual leptomeningeal dissemination in a child with extracranial metastatic alveolar rhabdomyosarcoma.

The authors describe a 6-year-old boy diagnosed with alveolar rhabdomyosarcoma located in the thigh, with distal metastases to lungs, bones, and bone marrow. A very good partial response to first-line chemotherapy was obtained, but the child developed fatal leptomeningeal dissemination immediately after complete resection of the primary tumor. This case demonstrates the rapidity with which leptomeningeal spread of extracranial metastatic alveolar rhabdomyosarcoma can occur and underscores the importance of diagnostic lumbar puncture and brain radiological investigations at diagnosis, even when the tumors are not in the parameningeal location.

SCMCIE94: an intensified pilot treatment protocol known to be associated with cure in CD 56-negative non-pelvic isolated Ewing sarcoma (EWS) is also associated with no early relapses in non-metastatic extremity EWS.

PURPOSE: We report the unexpected absence of early relapse (before 30 months) in 24 consecutive patients with isolated limb primary Ewing sarcoma treated with an intensified pilot protocol, SCMCIE94. METHODS: Clinical data for the study were collected retrospectively from the patient files. The protocol included 6 courses of chemotherapy, split radiation, and limb salvage surgery. This SCMCIE94 protocol had been used in almost all the patients described in an earlier report, in whom those with non-pelvic isolated tumors and low/absent CD56 expression in Ewing sarcoma tumor cells were all long-term survivors. RESULTS: The 5-year (10-year) event-free survival rate for the patients with isolated limb primary Ewing sarcoma was 78.95 ± 8.3% (68.6 ± 10.0%) and the overall survival rate was 90.7 ± 6.2% (71.1 ± 11.2%). There were no relapses before 30 months in any of these patients. CONCLUSION: The intensified SCMCIE94 pilot protocol has been shown previously to cure patients with localized CD56-negative non-pelvic Ewing sarcoma. The present study shows that among all patients with localized extremity disease who were treated with this protocol, there were no cases of early relapse. Although our cohort was small, the difference in results from studies using other protocols is so striking, that it would seem reasonable to assume it is attributable to the changes made in the protocol itself rather than risk factors. Late relapses of isolated limb CD56-positive Ewing sarcoma suggest minimal residual disease warranting additional therapeutic approaches such as autologous stem cell rescue after Busulfan Melfelan.

Short telomeres: a novel potential predictor of relapse in Ewing sarcoma.

PURPOSE: Despite advances in therapy, >50% of patients with Ewing sarcoma will relapse. The current prognostic factors are not optimal for risk prediction. Studies have shown that telomere length could predict outcome in different malignancies. Our aim was to evaluate whether telomere length could be a better prognostic factor in Ewing sarcoma and correlate the results with clinical variables, outcome, and chromosomal instability. EXPERIMENTAL DESIGN: Telomere length was determined in the primary tumor and peripheral blood of 32 patients with Ewing sarcoma. Chromosomal instability was evaluated by combining classical cytogenetics, comparative genomic hybridization and random aneuploidy. Telomere length was correlated to clinical variables, chromosomal instability, and outcome. RESULTS: In 75% of the tumors, changes in telomere length, when compared with the corresponding peripheral blood lymphocytes, were noted. The majority of changes consisted of a reduction in telomere length. Patients harboring shorter telomeres had a significantly adverse outcome (P = 0.015). Chromosomal instability was identified in 65% of tumors, significantly correlating with short telomeres (P = 0.0094). Using multivariate analysis, telomere length remained the only significant prognostic variable (P = 0.034). Patients with short telomeres had a 5.3-fold risk of relapse as compared to those with unchanged or longer telomeres. CONCLUSION: We have shown that tumors with telomere length reduction result in genomic instability. In addition, telomere length reduction was the only significant predictor of outcome. We suggest that reduction of telomere length in tumor cells at diagnosis could serve as a prognostic marker in Ewing sarcoma.

The complexity of management of pregnancy-associated malignant soft tissue and bone tumors.

OBJECTIVE: The incidence of musculoskeletal tumors during pregnancy is very low. The aim of this study was to summarize our experience in treating a large cohort of pregnant patients diagnosed with these rare tumors. METHODS: Women diagnosed with musculoskeletal tumors during pregnancy or immediately after delivery were identified retrospectively in our database between 1996 and 2006. Relevant maternal and neonatal data were collected. RESULTS: Twenty patients, 8 with bone sarcomas (BS) and 12 with soft tissue sarcomas (STS) were identified. Two women were treated by wide excision of mass during pregnancy. In all other cases oncological treatment was delayed until delivery or termination of pregnancy. Vaginal delivery was possible in 9 patients, cesarean section was performed in 7, spontaneous abortion occurred in 1, and 3 underwent termination of pregnancy. Three newborns were premature, but normal growth and development were observed. Different techniques of fertility preservation were used in our patients. Five patients with BS and 5 patients with STS received preoperative chemotherapy, with different grades of toxicity. The degree of tumor necrosis tended to correlate with dose-intensity of chemotherapy. Seven patients with BS received adjuvant chemotherapy. Two patients with STS received adjuvant chemotherapy, two - radiotherapy, and four - both modalities. Median disease-free survival was 15.1 months, median overall survival - 25.4 months. CONCLUSIONS: Musculoskeletal tumors diagnosed during pregnancy, or after delivery, do not appear to have a significant impact on the prognosis. A multidisciplinary team should tailor the oncological approach individually.

A histopathological review of gastrointestinal related mesenchymal tumors: the hidden GIST.

BACKGROUND: The diagnosis of gastrointestinal stromal tumors is based on documentation of c-KIT and platelet-derived growth factor-alpha receptors or specific c-KIT mutations. Before the diagnosis of GIST was possible, all cases had been classified as sarcomas or benign tumors. OBJECTIVES: To identify cases of GIST formerly diagnosed as abdominal or retroperitoneal mesenchymal tumors. METHODS: We reviewed the archive material on all surgical cases diagnosed as gastrointestinal related malignant mesenchymal tumors or GIST in our medical center during the last decade (1995-2004). RESULTS: Sixty-eight cases of retroperitoneal soft tissue sarcoma were identified. Thirty-eight were reconfirmed to be GIST, 19 were newly diagnosed as GIST (the hidden cases), 8 cases were re-diagnosed as mesenchymal tumors, and 3 cases of sarcoma remained sarcomas. Of all the GIST tumors, c-KIT-positive and PDGFRalpha-positive tumors were more characteristic of primary gastric tumors, while c-KIT-positive and PDGFRalpha-negative tumors were found in the colorectal area. The c-KIT-negative and PDGFRalpha-positive cases were of gastric origin. CONCLUSIONS: Any c-KIT-negative malignant mesenchymal mass located near the proximal gastrointestinal tract should also be stained for PDGFRalpha to differentiate between GIST and other soft tissue sarcomas. Practically, formerly diagnosed abdominal or retroperitoneal soft tissue sarcomas should be reviewed to identify patients with misdiagnosed GIST and thereby avoid future unnecessary and ineffective chemotherapy.

Sporadic desmoid tumors in the pediatric population: A single center experience and review of the literature.

BACKGROUND/PURPOSE: We present our long experience with desmoid tumors in children. METHODS: Data were retrospectively collected from 17 children/adolescents treated for sporadic desmoid tumors at a tertiary pediatric hospital in 1988-2016. There were 10 girls and 7 boys aged 1-17years. Tumor sites included head and neck, trunk, extremity, and groin. Eight patients underwent radical resection, with complete remission in 7 and local relapse in one which was treated with chemotherapy. Four patients underwent incomplete surgical resection, three with adjuvant chemotherapy. Five patients underwent biopsy only and chemotherapy. Two of the 9 chemotherapy-treated patients also had intraarterial chemoembolization. Chemotherapy usually consisted of vincristine and actinomycin-D with or without cyclophosphamide or low-dose vinblastine and methotrexate. Two patients also received tamoxifen. RESULTS: After a median follow-up of 3.3years, 10 patients were alive in complete remission, 5 had stable disease, and 2 had reduced tumor size. Five-year overall survival was 100%, and event-free survival, 87.5%. Ten were screened for CTNNB1 mutations. CTNNB1 gene sequencing yielded mutations in 5/10 samples tested: 3 T41A, 2 S45F. There was no association of CTNNB1 mutation with clinical outcome or prognosis. CONCLUSION: Pediatric desmoid tumors are rare, with variable biologic behavior and morbidity. Treatment requires a multidisciplinary approach. LEVEL OF EVIDENCE: LEVEL IV, treatment study.

Prediction of high risk Ewing's sarcoma by gene expression profiling.

Ewing's sarcoma (ES) is the second most common primary malignant bone tumor in children and adolescents. Currently accepted clinical prognostic factors fail to classify ES patients' risk to relapse at diagnosis. We aimed to find a new strategy to distinguish between poor and good prognosis ES patients already at diagnosis. We analysed the gene expression profiles of 14 primary tumor specimens and six metastases from ES patients, using oligonucleotide microarray analysis. The over-expression of two genes was validated by quantitative PCR using the LightCycler system. We identified two distinct gene expression signatures distinguishing high-risk ES patients that are likely to progress from low-risk ES patients with a favorable prognosis of long-term progression-free survival. The microarray-based classification was superior to currently used prognostic parameters. Over-expressed genes in the poor prognosis patients included genes regulating the cell cycle and genes associated with invasion and metastasis, while among the downregulated genes were tumor suppressor genes and inducers of apoptosis. Our results indicate the existence of a specific gene expression signature of outcome in ES already at diagnosis, and provide a strategy to select patients who would benefit from risk-adapted improved therapy.

Limb sparing approach: adjuvant radiation therapy in adults with intermediate or high-grade limb soft tissue sarcoma.

BACKGROUND: Limb soft tissue sarcomas (STS) are currently treated with limb sparing surgery (LSS) followed by radiation therapy (RT). PATIENTS AND METHODS: Between October 1994 and October 2002, 133 adult patients with intermediate or high-grade limb STS were approached by LSS+RT. RESULTS: RT related toxicity was manageable, with a low rate of severe effects. At 4-year median follow-up, there were 48 recurrences of any type, 23 of isolated local failure, and 35 of systemic spread w/o local failure. DFS and OS were influenced by disease stage II vs I, primary site in the upper limb vs lower limb, MPNST vs other types, induction therapy vs no induction, adequate resection vs marginal resection or involved margins, and good response to induction therapy vs bad response. DFS and OS were Patient's age and sex, tumor depth, acute or late toxicity of RT, or the interval of time between the date of definitive surgery and the start of RT did not affect DFS and or OS. CONCLUSIONS: The RT protocol is applicable in the era of complicated, expensive and time-consuming 3D therapy. Our results of LSS+RT in adults with limb HG STS are satisfactory.

A single-team experience of limb sparing approach in adults with high-grade malignant fibrous histiocytoma.

Malignant fibrous histiocytoma (MFH) is the most common subtype of soft-tissue sarcoma (STS). When located in a limb, MFH, is currently treated with limb sparing surgery (LSS) followed by radiation therapy (RT). During 8 years, 42 adult patients with high-grade limb MFH were approached by LSS and RT. Our results reflect a single-team experience and point to several important conclusions. High grade MFH, treated by conservative approach, lead to a 10-year relapse-free survival of 62% and a 10-year overall survival rate of 80%. Recurrences of MFH tend to occur during the first 2 years. Relapse-free survival was affected mainly by location in the lower limb vs. the upper limb, irrespective of the tumor size. Patients who had their diagnostic biopsies in another medical center had a greater tendency to local and systemic relapse. It seems that the most important clues for disease-free survival are the team experience and cooperation. All other factors are tumor-biology dependent, and thus far are beyond our control.

Highly effective reduced toxicity dose-intensive pilot protocol for non-metastatic limb osteogenic sarcoma (SCOS 89).

PURPOSE: Aggressive chemotherapy protocols for non-metastatic limb osteosarcoma have improved histological response without affecting prognosis. This study evaluated the toxicity and outcome of a dose-intensive, high-dose 3- to 5-drug pilot protocol, SCOS 89. METHODS: The cohort included 26 patients (14 male; ages 6.5-22 years) with non-metastatic limb osteosarcoma treated at a tertiary pediatric medical center between 1989 and 2013. Preoperatively, patients received two courses of once-weekly pulses of high-dose methotrexate (12-30 g/m(2)) for 2 weeks; doxorubicin (90 mg/m(2)) with dexrazoxane, combined with cisplatin (200 mg/m(2)), was added in week 3. Following methotrexate, 760 mg/m(2) of folinic acid was administered. Postoperative chemotherapy was continued to a total of 14 courses of methotrexate, doxorubicin (up to a total dose of 360 mg/m(2)), and cisplatin (up to a total dose of 560 mg/m(2)). If toxicity occurred or <90 % tumor necrosis, ifosfamide (12 g/m(2)) plus etoposide (500 mg/m(2)) was substituted for doxorubicin, cisplatin, or methotrexate. Toxicity and death rates were calculated. RESULTS: All patients underwent definitive limb salvage surgery. Six patients died of infection, recurrent disease, or secondary malignancy. Median follow-up was 100 months (range 2-290). Event-free and overall survival rates, respectively, were 88 and 96 % at 2 years, 80 and 87.6 % at 5 years, 80 and 78 % at 10 years. Eleven patients required ifosfamide/etoposide substitution. One patient had a transient decreased left ventricular ejection fraction. Two patients developed acute nephrotoxicity during therapy, but no neurotoxicity. Seven patients had hearing impairment. CONCLUSIONS: The SCOS 89 yields a high event-free survival rate with reduced nephro-/neuro-/cardiotoxicity in patients with non-metastatic limb osteosarcoma.

The association between let-7, RAS and HIF-1α in Ewing Sarcoma tumor growth.

Ewing Sarcoma (ES) is the second most common primary malignant bone tumor in children and adolescents. microRNAs (miRNAs) are involved in cancer as tumor suppressors or oncogenes. We studied the involvement of miRNAs located on chromosomes 11q and 22q that participate in the most common translocation in ES. Of these, we focused on 3 that belong to the let-7 family.We studied the expression levels of let-7a, and let-7b and detected a significant correlation between low expression of let-7b and increased risk of relapse. let-7 is known to be a negative regulator of the RAS oncogene. Indeed, we detected an inverse association between the expression of let-7 and RAS protein levels and its downstream target p-ERK, following transfection of let-7 mimics and inhibitors. Furthermore, we identified let-7 as a negative regulator of HIF-1α and EWS-FLI-1. Moreover, we were able to show that HIF-1α directly binds to the EWS-FLI-1 promoter. Salirasib treatment in-vitro resulted in the reduction of cell viability, migration ability, and in the decrease of cells in S-phase. A significant reduction in tumor burden and in the expression levels of both HIF-1α and EWS-FLI-1 proteins were observed in mice after treatment.Our results support the hypothesis that let-7 is a tumor suppressor that negatively regulates RAS, also in ES, and that HIF-1α may contribute to the aggressive metastatic behavior of ES. Moreover, the reduction in the tumor burden in a mouse model of ES following Salirasib treatment, suggests therapeutic potential for this RAS inhibitor in ES.

Radiotherapy for spinal cord compression in patients with soft-tissue sarcoma.

PURPOSE: Spinal metastases of soft-tissue sarcoma (STS) occur rarely and pose a therapeutic problem. Although wide resection is warranted for best local control, it is rarely feasible. A radiotherapy (RT) dose of 70 Gy is usually needed to treat limb STS, but only 45 Gy can be given to the spine. In the present series, we report our experience using RT to treat spinal cord compression (SpCC) associated with STS. METHODS AND MATERIALS: The medical files of 19 adult patients with STS and SpCC were reviewed. RT was considered in all the cases, together with steroids and analgesics. The prescribed dose was 30 Gy in 10 fractions within 12 days. The effect of treatment was evaluated on a clinical basis. RESULTS: Twenty-three events of SpCC were found. The prevailing symptom was pain. The Karnofsky performance status was 40-70% at presentation. RT was given in all but 1 patient and surgical decompression in 3. Small, but important, improvements in signs and Karnofsky performance status were noted in 14 of 23 cases of SpCC, expressed mainly by pain alleviation and restoration of independence. The median survival after the diagnosis of SpCC was 5 months. CONCLUSION: Radiotherapy is an important tool in palliating SpCC in patients with STS.

Expression of p53 gene product and cell proliferation marker Ki-67 in Ewing's sarcoma: correlation with clinical outcome.

Overexpression of tumor suppressor gene p53, cell proliferation nuclear antigen Ki-67, and proto-oncogene HER-2/neu are associated with poor prognosis in some tumors. We studied p53, Ki-67, and HER-2/neu immunohistochemical expression in archival biopsies of 37 patients with Ewing's sarcoma (ES). Patients with ES were treated at four Israeli hospitals between 1982 and 2000. Formalin-fixed paraffin-embedded tissue sections were stained by immunohistochemistry for p53, Ki-67, and HER-2/neu. More than 300 cells were counted on each slide, and the percentage of positively stained nuclei was computed. p53 overexpression was defined as nuclear staining of >2.3% of cells, Ki-67 overexpression as nuclear staining of >8.3% malignant cells. HER-2/neu staining was scored semiquantitatively on a scale of 0 to 4+. Twenty-two of 37 patients are alive and well, with mean follow-up time of 38 months. There was overexpression of p53 in 16 patients (43%) and of Ki-67 in 21 patients (57%). The correlation between p53 and Ki-67 overexpressions was 0.61. We found no overexpression of HER-2/neu. Median relapse-free survival (RFS) was statistically significantly shorter for patients with p53 overexpression (25 months) than for patients with negative staining (>92 months). The prognostic value of p53 overexpression was also significant after adjusting for tumor location and age. Median RFS was shorter for patients with positive Ki-67 staining (40 months) than for patients with negative staining (80 months) but did not reach statistical significance. Our study suggests that p53 is a predictor of RFS in patients with ES. More patients must be studied to assess the validity of this observation.

Localization of a specific germ cell marker, DAZL1, in testicular germ cell neoplasias.

DAZ-like 1( DAZL1) is a germ cell-specific protein expressed in both male and female gonads. The DAZL1 gene, which maps to chromosome 3 in humans, is an autosomal homologue to the Deleted in AZoospermia ( DAZ) gene(s) located on the Y chromosome. We studied the expression of DAZL1 by means of immunohistochemistry in order to determine its distribution among testicular germ cell neoplasias and among the intratubular lesions in their vicinity. Our results demonstrated that expression of DAZL1 protein was consistently observed in scattered cells in all intratubular germ cell neoplasias (IGCN) of the unclassified type, as well as in some of the intratubular seminomas. Foci of DAZL1 immunopositive cells were detected in pure seminomas, while single immunopositive cells were dispersed in the seminomatous component of mixed germ cell neoplasias. All the nonseminomatous components were negative for DAZL1 expression. These findings demonstrate an antigenic heterogeneity of seminoma cells. The localization of a specific germ cell protein, DAZL1, in the putative ontogenic progenitor, IGCN, and in their putative derivative, seminoma, provides further support for the hypothesis that IGCN is the precursor of germ cell neoplasias.