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PubMed2004

Characterization of sarcomas by means of gene expression.

Sarcomas represent a heterogeneous group of diseases of a variety of recognized histologic types. Among these subtypes is malignant fibrous histiocytoma (MFH), a diagnosis no longer recognized as a specific diagnosis at some institutions. In this study, gene expression in 38 histologically well-defined sarcoma samples, 17 MFH samples, 12 samples of sarcomas classified simply as high-grade sarcoma (NOS, standing for "not otherwise specified"), and 26 other mesenchymal tumors was determined at Gene Logic Inc (Gaithersburg, MD), with the use of Affymetrix GeneChip U_133 arrays containing approximately 40,000 known genes and expressed sequence tags (ESTs). Gene-expression analysis was performed with the use of the Gene Logic Gene Express(R) Software System. Differences in gene expression were quantified as the fold change in gene expression between the various sets of well-defined sarcomas. A set of genes was then identified that could be used to distinguish the well-defined sets of 11 liposarcomas, 9 leiomyosarcomas, 4 synovial sarcomas, 8 schwannomas, and 12 cases of aggressive fibromatosis through the use of Eisen clustering. Eisen clustering was then repeated with the same set of gene fragments with the sample set of 38 histologically well-defined sarcomas, the 17 sarcomas classified as MFH, 12 sarcomas classified as high-grade sarcoma (NOS), and 26 other mesenchymal tumors. Under these conditions, each of the samples of well-defined sarcoma formed distinct clusters that contained some of the MFH and NOS samples. In addition, distinct clusters were observed that contained only MFH and NOS samples. We conclude that gene-expression patterns may be useful in helping further classify subtypes of sarcomas.

Adult↗
PubMed1995

Frequent incidence of extrapulmonary sites of initial metastasis in patients with liposarcoma.

BACKGROUND: The vast majority of soft tissue sarcomas spread initially to the lungs and then to other sites. The lung has been the most carefully monitored organ system during routine surveillance for a metastasis. Liposarcoma is one of the most common soft tissue sarcomas and has been noted to have extrapulmonary sites of initial metastasis. This study was undertaken to investigate both the frequency and distinguishing features of initial extrapulmonary metastasis in patients with liposarcoma. METHODS: A review of 60 patients with liposarcoma treated at the Massachusetts General Hospital (MGH) from 1971 to 1990 was performed. Survival and regression analyses were used to analyze disease free intervals and prognostic factors. RESULTS: Metastatic disease occurred in 37% of patients and local failure in 17%. Among the subset of patients who underwent primary definitive surgery at the MGH, the incidence of local failure was 3%. An unusually high incidence of extrapulmonary site of first metastasis was found. Isolated extrapulmonary disease was the site of initial metastasis in 59% of patients. In contrast to patients with an initial pulmonary metastasis, patients with an initial extrapulmonary metastasis had a statistically significant (P = 0.001) longer disease free interval from diagnosis to first metastasis. CONCLUSIONS: Liposarcoma, in comparison with other soft tissue sarcomas, has a different pattern of metastatic spread, with a tendency toward extrapulmonary sites. In addition, patients with extrapulmonary metastases have a longer disease free interval compared with patients with pulmonary metastasis.

Adolescent↗
PubMed1999

Comparative genomic hybridization reveals novel chromosome deletions in 90 primary soft tissue tumors.

Comparative genomic hybridization (CGH) was used to detect chromosomal gains and losses in a series of 90 frozen soft tissue primary tumors (STTs), all untreated. The material consisted of 69 malignant sarcomas, including 20 malignant fibrous histiocytomas (MFH), 23 liposarcomas (LPS), 6 leiomyosarcomas (LMS), 4 synovial sarcomas, 4 primitive neuroectodermal tumors (PNETs), and various others subtypes, in addition to 21 benign tumors. Within the benign tumors, only 2 of the 3 schwannomas showed genetic changes. In malignant sarcomas, genetic changes were detected in 64 of the 69 samples analyzed (92%), with a mean of 4.5 per sample (range 0-10). Gains and losses on chromosome 13 were observed in 32% of the sarcomas with genomic imbalance. Recurring low-level copy number increases were found at new sites on chromosomes 7 (6 MFH samples, 30%) and 8 (10 LPS samples, 43%), the minimal common regions being 7p15-pter and 8q24. No new recurring high-level amplifications were found. Surprisingly, losses of DNA sequences were more frequent than gains; particularly, losses were the main feature in LMS, with highly recurrent common minimal losses at 11q14-qter and 13q21-q22 (4 samples, 66%, and 5 samples, 83%, respectively). Losses of chromosome 2 sequences (minimal common regions at 2p24-pter and 2q32-qter) were observed in 50% of the MFH analyzed. New recurrent losses of whole or part of chromosome 14 were found in 57% of the pleomorphic LPS (PLPS) analyzed. This study uncovers new clues for the diagnosis of malignant STTs and shows the importance of deletions as events in the early steps involved in the tumorigenesis of STTs.

Chromosome Deletion↗
PubMed1996

Molecular and immunohistochemical identification of p53 alterations in bone and soft tissue sarcomas.

p53 has been shown to suppress tumor growth by regulating the cell cycle and by triggering apoptosis. Acquired somatic mutations of the p53 gene have been observed in a variety of human malignancies, and these result in a loss of its tumor suppressor function. To examine the occurrence of p53 abnormalities in bone and soft tissue sarcomas, 113 tumors were subjected to molecular analysis and mutations were confirmed in 16 tumors. The frequency of p53 alterations varied among the different subtypes of bone and soft tissue sarcomas, being observed predominantly in osteosarcomas (8/34 cases), rhabdomyosarcomas (2/3 cases), Ewing's sarcomas (1/5 cases), and liposarcomas (3/21 cases). In contrast, p53 gene mutations were detected at a lower frequency in malignant fibrous histiocytomas (2/34 cases) and not at all in nine chondrosarcomas and five leiomyosarcomas. Immunohistochemical staining of p53 protein was performed on 69 cases and compared to the DNA results. For 64 cases the results were concordant: 56 sarcomas were considered to have wild-type p53 by both techniques. As well, increased p53 protein expression was observed in eight of the nine tumors with p53 gene mutations. However, positive p53 staining was also seen in four sarcomas which had no detectable p53 mutations in exons 5 through 9. Because some sarcomas exhibit amplification and overexpression of MDM-2, which may interact with p53 and cause stabilization of wild-type p53 protein, we examined these tumors for MDM-2 amplification. None of the tumors with MDM-2 amplification exhibited p53 immunopositivity. Very weak p53 reactivity was detected in four malignant fibrous histiocytomas that had received either chemotherapy or radiotherapy. Of 16 metastatic lesions examined, only one contained a p53 mutation. In addition, for five cases in which both the original lesion and its metastases were analyzed, p53 alterations were not observed in the metastases if the tumor was wild-type at presentation. These data suggest that p53 alterations occur at different frequencies in various subtypes of sarcoma and, although detected in metastatic lesions, are not associated more frequently with progression.

Bone Neoplasms↗
PubMed1998

Primary sarcomas of the mediastinum: results of therapy.

UNLABELLED: Primary sarcomas of the mediastinum are rare, and data concerning treatment and results of therapy are sparse. OBJECTIVE: To assess presentation, management, prognostic factors, and survival in mediastinal sarcomas. METHODS: We reviewed our experience with 47 patients with the diagnosis of primary sarcoma of the mediastinum. Data were collected from a computerized institutional database and medical records. Survival was analyzed by Kaplan-Meier method and comparisons of survival by log rank test. RESULTS: The median age of 47 patients with mediastinal sarcoma was 39 years (range 2.5 to 69 years), with a male/female ratio of 1.6. The most common complaints were chest/shoulder pain (38%) and dyspnea (23%). The most common tumor types were malignant peripheral nerve tumor (26%), spindle cell sarcoma (15%), leiomyosarcoma (9%), and liposarcoma (9%). Operation was the primary treatment modality in 72% of cases (n = 34); 22 sarcomas (47%) were completely resected. The overall 5-year survival was 32%. High-grade lesions had a significantly decreased survival (5-year survival = 27%) compared with low-grade tumors (5-year survival = 66%) (p = 0.05). The overwhelming factor determining survival was the ability to completely resect the tumors (5-year survival 49% for complete resection; 3-year survival 18% for incomplete or no resection) (p = 0.0016). Despite complete resection, local recurrence occurred in 64% of cases. CONCLUSION: Because the overall survival for patients with mediastinal sarcomas is 32% and the local recurrence is 64% for tumors completely resected, aggressive adjuvant therapy should continue to be systematically explored.

Adolescent↗
PubMedDate not supplied

p53/MDM-2 immunohistochemical expression correlated with proliferative activity in different subtypes of human sarcomas: a ten-year follow-up study.

The aim of this study was the evaluation of p53/MDM-2 protein overexpression in different subtypes of human sarcomas, and their correlation with proliferative activity and patient outcome. We selected 40 cases of human sarcomas comprising 6 malignant fibrous histiocytomas (MFH), 1 fibrosarcoma, 1 dermatofibrosarcoma protuberans, 5 liposarcomas, 9 leiomyosarcomas, 1 rhabdomyosarcoma, 3 synovial sarcomas, 2 osteosarcomas, 1 chondrosarcoma, 4 Ewing's sarcomas, 2 Kaposi's sarcomas, 1 malignant haemangiopericytoma, 1 phylloides cystosarcoma, 1 neuroblastoma, 1 chordoma and 1 unclassified sarcoma. All the immunohistochemical markers, which had been used for the characterization of these sarcomas were re-examined. Additionally, the Streptavidin-Biotin peroxidase method was performed on paraffin sections using the monoclonal antibodies: anti-p53 antibody DO7, anti-MDM-2 antibody IF2 and anti-Ki-67 antibody MIB-1. According to our results, p53 protein nuclear expression was detected in 20% (8/40) of the tumours (1 fibrosarcoma, 2 liposarcomas, 1 leiomyosarcoma, 1 rhabdomyosarcoma, 2 Ewing's sarcomas and 1 unclassified sarcoma). MDM-2 nuclear staining was determined in 7.5% (3/40) of the cases (1 MFH and 2 liposarcomas). A high proliferative index was demonstrated in 27.5% (11/40) of the tumours (2 MFH, 4 leiomyosarcomas, 1 rhabdomyosarcoma, 1 osteosarcoma, 2 Ewing's sarcomas and 1 unclassified sarcoma). p53 overexpression was associated with high tumour grade (p < 0.05) and MIB-1 expression was correlated with reduced survival (p < 0.05), but p53 overexpression was not significantly associated with either MIB-1 score or with overall survival of the patients. In conclusion, from this limited and heterogeneous sample of cases, we suggest that the p53/MDM-2 pathway is involved in the tumourigenesis of several sarcoma subtypes, but it is unclear if the overexpression of these genes may become prognostic marker for patients affected with these highly aggressive tumours.

Adolescent↗
PubMedDate not supplied

Immunohistochemical detection of bcl-2 and p53 proteins and apoptosis in soft tissue sarcoma: their correlations with prognosis.

Information on prognostic factors is essential to establish appropriate therapeutic modalities for soft tissue sarcoma (STS). To evaluate the biological nature and prognostic factors of STS, p53 and bcl-2 expression was immunohistochemically studied on paraffin-embedded sections from 70 patients with STS in the extremities and trunk. In addition, the degree of apoptosis was examined by in situ end-labeling. Histologic diagnoses in these cases were malignant fibrous histiocytoma in 29 cases, liposarcoma in 11, synovial sarcoma in 11, leiomyosarcoma in 5, malignant neurogenic tumor in 5, and others in 9. Tumor cells in 31 of 70 cases (44%) showed positive nuclear staining for p53 protein. There was no correlation between p53 expression and tumor size, histologic grade, argyrophilic nucleolar organizer region (AgNOR) count, cellularity and extent of neerosis. Expression of p53 did not correlate with survival of patients. Tumor cells in 24 of 56 cases (43%) were positive for bcl-2 protein expression. The frequency of bcl-2 expression in the tumor cells showed a direct proportion to tumor size (> or = 10 vs. < 10 cm) but inverse proportion to AgNOR counts and cellularity. The 5-year survival rate in patients with bcl-2-positive tumors (87%) was more favorable than in those with bcl-2-negative tumors (53%; p < 0.05). The frequency of apoptosis in low-grade STS was significantly higher than that in the intermediate and high-grade STS (p < 0.001). Extent of necrosis, a well-known prognostic indicator in STS, was not correlated with the frequency of apoptosis. Multivariate analysis showed that cellularity, bcl-2 and AgNOR counts were independent prognostic factors in patients with STS. The current study revealed that STS with a higher expression of bcl-2 had lower proliferative activity and larger size than those without. Immunohistochemical detection of bcl-2 is useful for predicting prognosis in patients with STS.

Adolescent↗
PubMed2006

Adult genitourinary sarcoma: the 25-year Memorial Sloan-Kettering experience.

PURPOSE: Urological sarcomas are rare. We describe a continued single institutional experience during 25 years. MATERIALS AND METHODS: The records from July 1977 to July 2003 were reviewed of all patients at our institution with sarcoma arising in the urinary tract or male genital system who were 16 years or older at diagnosis. RESULTS: The primary tumor site in 131 patients was the bladder in 20, the kidney in 26, paratesticular in 57, the prostate in 21 and other in 7. Median followup was 4.0 years. The most common histological subtypes were leiomyosarcoma in 29% of cases and liposarcoma in 26%. Median tumor size was 7 cm and 78% of lesions were high grade. Of the patients 28 (21%) presented with metastatic disease and their median survival was 1.4 years compared to 10.7 years in patients without metastatic disease (p < 0.0001). Disease specific survival was 56% and 42% at 5 and 10 years, respectively and median survival was 7.6 years. On univariate analysis unfavorable prognostic variables for disease specific survival were metastasis at presentation, high tumor grade, a lack of leiomyosarcoma and liposarcoma histological subtypes, prostate sarcoma and large tumor size, incomplete surgical resection and positive surgical margin. Patient sex, age and surgical margin status were not significant predictors. On multivariate analysis 2 variables remained significant predictors of disease specific survival, including tumor size (HR 1.1, 95% CI 1.02 to 1.17) and absent metastasis at diagnosis (HR 4.9, 95% CI 1.4 to 17.2). CONCLUSIONS: Predictors of disease specific survival include local disease at presentation, complete tumor resection and tumor grade, size, location and histological subtype. With adequate surgical treatment most patients who presented with primary disease and underwent complete surgical resection achieved prolonged disease specific survival.

Adolescent↗
PubMed2004

Expression of DOL54 is not restricted to myxoid liposarcomas with the FUS-DDIT3 chimera but is found in various sarcomas.

The DOL54 gene [also known as megakaryocyte stimulating factor, articular superficial zone protein (SZP) or proteoglycan 4 (PRG4)], was cloned as a downstream target gene of the FUS-DDIT3 chimera, which is the fusion gene that characterizes myxoid liposarcoma (MLS). Activation of DOL54 was found to require an intact DNA binding domain of the DDIT3 protein and to be dependent on the presence of the N-terminal part of the FUS protein. Although originally suggested to be of oncogenic significance, expression analysis of DOL54 in tumors has so far been limited to a few cases of liposarcoma and malignant fibrous histiocytoma (MFH). In the present study we were interested to evaluate whether DOL54 expression can be associated with other fusion genes in which FUS is the 5'-partner. Thus, we investigated the expression of DOL54 in low grade fibromyxoid sarcoma (LGFMS) carrying the FUS-BBF2H7 chimeric transcript. We also included synovial sarcomas (SS), Ewing tumors (ET), extraskeletal myxoid chondrosarcomas (EMC) and MFH. The first 3 of these tumor types are characterized by chromosomal translocations that give rise to fusion genes not involving FUS, while no specific chimeric genes have been reported in MFH. DOL54 expression was found in 8/12 LGFMS carrying the FUS-BBF2H7 chimera but also in 8/10 of the examined MFH, 5/7 SS, 2/5 ET and 7/7 examined EMC. The results of our study clearly show that expression of DOL54 is not only a characteristic feature of MLS with the FUS-DDIT3 chimera but that this is a frequent finding also in various other sarcomas.

Cloning, Molecular↗
PubMed2003

Primary pulmonary sarcomas and carcinosarcomas--postoperative results and comparative survival analysis.

OBJECTIVE: To evaluate the early and long-term results after surgery for primary pulmonary sarcomas (PPS) and to compare them with those of patients with pulmonary carcinosarcomas (PCaSa). METHODS: During a 20-year period, 48 patients with PPS and 15 patients with PCaSa underwent surgery. There were 40 males and 23 females with a mean age of 52.1 years (range 13-78). The histologic diagnoses in PPS group were fibrosarcoma (15), fibroleiomyosarcoma (10), leiomyosarcoma (6), rhabdomyosarcoma (6), hemangiopericytoma (3), epitheloid hemangioendothelioma (3), malignant schwannoma (1), liposarcoma (1) and undifferentiated sarcoma (3). The following curative resections were carried out: lobectomy (36), including two sleeve lobectomies (in PPS group), pneumonectomy (15) and polysegmental resections (4). In four PPS cases, these procedures were extended to the thoracic wall, diaphragm or pericardium. An atypical resection was applied in one PPS patient (the tumor was falsely classified as benign on frozen section examination). Exploratory thoracotomy was performed in five of PPS patients (11%) and in two of those with PCaSa (13%). The majority of PPS patients were with low stages I and II (76%). The PCaSa patients were predominantly with stage IIIA (39%). RESULTS: No postoperative death was registered. Major complications included two localized empyemas (4.2%) in PPS and one reoperation for bronchial stump fistula (6.7%) in PCaSa groups. Local recurrences were operated on in one patient per group (2.1 and 6.7%, respectively). Follow-up was available on 57 patients and ranged from 4 to 148 months. The overall cumulative 5-year survival was 48.81% for PPS and 49.38% for PCaSa patients (P=0.9035). It was better in low vs. higher stage cases, statistically significant in PPS group (P=0.0005) and without significant difference in PCaSa cohort (P=0.11). CONCLUSIONS: Complete resection of PPS and PCaSa favors an acceptable survival, especially in low stages. There is no significant difference in the survival rates between PPS and PCaSa patients, despite the greater number of cases with higher stages in PCaSa group.

Adolescent↗
PubMedDate not supplied

[A case of perirenal myxoid liposarcoma].

Radical operation of a right perirenal myxoid liposarcoma is reported. Retroperitoneal sarcomas, in fact, show little response to antiblastic and radiation management. It is pointed out that angiographic diagnosis is an essential prelmiminary to correct surgical indication, particularly since the clinical picture may well be indistinct and poorly specific.

Aged↗
PubMed1999

Soft tissue sarcomas of infancy.

Malignancy occurring during the neonatal period (defined as the first 28 days of life) is over 3 times the incidence of other pediatric age groups. Of all neoplasia occurring in infants, benign and malignant, 25% are soft tissue tumors. Differentiating the benign lesions from the 15% that are malignant can be difficult. This article discusses the epidemiology, differential diagnosis, evaluation, and treatment of infants with soft tissue sarcomas. Fibrosarcoma and rhabdomyosarcoma are also discussed at length. The authors review other rare tumors as well. The impact on diagnosis of molecular techniques is included when appropriate. A multidisciplinary team approach for treatment of these infants is recommended.

Diagnosis, Differential↗
PubMed2002

Immunohistochemical staining for KIT (CD117) in soft tissue sarcomas is very limited in distribution.

We performed immunohistochemical analysis for KIT in 365 soft tissue sarcomas. Most tumors evaluated were completely negative for KIT, including all cases of leiomyosarcoma, rhabdomyosarcoma, myxofibrosarcoma, liposarcoma, solitary fibrous tumor, synovial sarcoma, dermatofibrosarcoma protuberans, schwannoma, malignant peripheral nerve sheath tumor, clear cell sarcoma, low-grade endometrial stromal sarcoma, and follicular dendritic cell sarcoma. Tumors showing occasional immunoreactivity for KIT included extraskeletal myxoid chondrosarcoma (2/20), Ewing sarcoma/malignant primitive peripheral neuroectodermal tumor (4/20), melanotic schwannoma (3/5), metastatic melanoma (4/20), and angiosarcoma (5/20). In most cases, staining for KIT was focal. Rare tumor cells showing KIT positivity were identified in a small number of other tumors. This study demonstrates very limited expression of KIT in soft tissue tumors other than gastrointestinal stromal tumors and underscores the discriminatory value of KIT immunohistochemical analysis for differential diagnosis. As some of these findings differ markedly from previous reports, it is evident again that variations in immunohistochemical technique can lead to major discrepancies in positive staining. Since treatment eligibility for selective tyrosine kinase inhibitors such as STI571 hinges on positive immunostaining, standardization and reproducibility of meaningful results are critically important.

Chondrosarcoma↗
PubMed2005

Myxoid malignant fibrous histiocytoma and pleomorphic liposarcoma share very similar genomic imbalances.

Malignant fibrous histiocytoma (MFH) is the most common soft tissue sarcoma. Nevertheless, the validity of this heterogeneous pathological entity has been recurrently questioned by pathologists. Recently, analyses by comparative genomic hybridization (CGH) of a large series of MFHs suggested that MFHs consist of morphologic modulation of other poorly differentiated sarcomas like leiomyosarcomas (LMS) or dedifferentiated liposarcomas (DLPS). We report here an analysis by CGH of 22 myxoid MFHs (mMFH), one of the five histological subtypes of MFH, and of nine pleomorphic liposarcomas (pLPS), a rare poorly differentiated LPS. The chromosome imbalances encountered in the series of mMFH were very similar to those observed in the series of pLPS studied in the laboratory and in the series of 14 pLPS published in the literature. The most frequent gains involved chromosome subregions: pericentromeric regions of 1, 5p, 19p, 19q and 20q. Losses found in the chromosomal arms 1q, 2q, 3p, 4q, 10q, 11q and 13q were also recurrent. The use of a clustering software did not separate the two pathological groups (mMFH and pLPS) on the basis of genomic data. Moreover, pLPS-mMFH represented, according to the clustering software results, an entity clearly distinguished from other soft tissue sarcomas, LMS in particular, with which they share common genetic aberrations. Additional studies are needed to identify genes targeted by these genomic aberrations, and implicated in the oncogenesis of these tumor subtypes. The characterization of common gene alterations in both tumor groups would suggest a closer relationship between these two types of soft tissue sarcomas.

Adult↗
PubMed1986

Liposarcoma. An ultrastructural study of 15 cases.

Fifteen liposarcomas from 13 patients were examined by electron microscopy. These included nine primary tumors, four recurrent tumors after primary surgery or irradiation, and two metastatic lesions. Twelve of the liposarcomas were located in the thigh, and 11 were of the myxoid variety. All neoplasms were composed of cells having the ultrastructural characteristics of some stage of lipoblastic differentiation, i.e., lipid droplets, micropinocytotic vesicles, glycogen, external lamina, intermediate filaments, Golgi apparatuses, rough and smooth endoplasmic reticulum, and mitochondria. The nuclear-cytoplasmic ratio and nuclear pleomorphism were related inversely to the size and number of lipid droplets. Lipoblasts were frequently in close association with capillaries and pericytes, and in four cases lipid droplets were found in pericytes. Multivacuolated, mitochondria-rich lipoblasts, resembling brown fat cells, also were seen. Most tumors contained lipid-free, poorly differentiated mesenchymal cells that showed a continuum of morphologic differentiation to cells that closely resembled early lipoblasts that contained nonmembrane-bound lipid vacuoles. Fibrolipoblasts, cells containing lipid droplets and abundant rough endoplasmic reticulum, were observed only in well-differentiated liposarcomas. Some soft tissue sarcomas contain vacuolated cells that simulate lipoblasts by light microscopy but prove to be reactive or malignant fibroblasts, histiocytes, or smooth muscle cells ultrastructurally. Therefore, use of electron microscopy may be necessary to establish the line of differentiation in these neoplasms.

Adolescent↗
PubMed2006

Sarcomas often express constitutive nitric oxide synthases (NOS) but infrequently inducible NOS.

Nitric oxide (NO) has a dual action in tumors, with both pro-tumor and anti-tumor activities. NO is produced by nitric oxide synthases (NOS). There are three enzyme isoforms: two of them are constitutively produced (neuronal or brain NOS and endothelial NOS), and one is an inducible form (iNOS). NOS expression has been shown in several epithelial tumors, but there is no report addressing NOS expression in sarcomas. The authors evaluated the expression of NOS in 97 cases of various sarcomas spotted in duplicate in a tissue array paraffin block. Eighty-four of the 97 tumor specimens (86.6%) expressed nNOS, and most of them showed a strong expression of the isoenzyme. Only chondrosarcomas and liposarcomas had significant numbers of negative cases, and all pleomorphic sarcomas, alveolar soft part sarcomas, angiosarcomas, gastrointestinal stromal tumors, and synovial sarcomas showed some degree of positivity. Forty-three cases (44.4%) showed eNOS immunostaining, but only 15.5% showed a strong signal, with emphasis on angiosarcomas, chondrosarcomas, alveolar soft part sarcomas, and synovial sarcoma. Strong expression of iNOS was observed in only 9 cases (9.3%), with weak expression in another 26 cases (26.8%). Strong expression of iNOS was found in malignant peripheral nerve sheet tumors, liposarcomas, pleomorphic sarcomas, fibrosarcomas, chondrosarcomas, and synovial sarcomas. Apparently alveolar soft part sarcomas are unusual in their capacity of expression of NOS isoforms, and in a very peculiar pattern. In conclusion, sarcomas in general commonly express constitutive NOS, and only a few types of sarcomas can express iNOS, the isoenzymes capable of releasing large amounts of NO. More comprehensive studies should be performed to better understand the clinical importance of NOS expression and NO production in sarcomas.

Humans↗