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Implanted solid human tumours grow under the renal capsule of cyclosporin-immunosuppressed rats.

Cyclosporin (CsA) is a potent immunosuppressive drug widely used in organ transplantation. We transplanted fresh surgical samples from human solid malignant tumours into 45 CsA-immunosuppressed rats. Eight out of nine tumour types grew and remained viable for 5 weeks or more in at least two of the transplanted rats. In 29 rats (64%) a distinct growth of primary human tumours was recorded. Five malignancies (intestinal-type gastric carcinoma, adenocarcinoma of the lung, lymph node metastasis of a testicular teratocarcinoma, soft tissue malignant fibrous histiocytoma (MFH), and small-cell sarcoma) showed invasive and progressive growth. In all five cases the largest tumours were 0.9 cm or over in diameter when the rats were killed 5-9 weeks after transplantation. In three cases (adenocarcinoma of the colon, hypernephroma, and a second MFH) the growth of the implants under the kidney capsule was slow, but small living tumour transplants were still found 3-6 weeks later. In every case the microscopic morphology of the xenograft tumour was identical with the original tumour. In two cases the primary xenografts (teratocarcinoma and small-cell sarcoma) were retransplanted into 11 CsA-immunosuppressed rats. In both types the second passage tumours grew, and the take-off and growth rates were comparable to the primary xenografts. Cyclosporin-treated laboratory rats are an alternative to immunodeficient nude and SCID mice for growing fresh human tumour transplants in vivo. Although a few infections were encountered, most of the rats survived the CsA treatment well for up to 2 months.

Animals↗

Current management of chest-wall tumors.

Chest-wall resection can be performed with low morbidity and mortality rates and remains the primary treatment for most chest-wall tumors. However, some lesions are best treated with a multimodality approach including preoperative chemotherapy. Therefore, pretreatment tissue diagnosis is essential in planning. The biopsy should be done at the medical center where the definitive treatment will be undertaken, and frequently, a needle biopsy will be sufficient. Osteosarcoma, rhabdomyosarcoma, Ewing's sarcoma, and other small-cell sarcomas are sensitive to chemotherapy, which should be given preoperatively, continued postoperatively, and modified according to the tumor response. Chondrosarcomas and most adult soft-tissue sarcomas are well controlled by primary excision and selective use of adjuvant irradiation. Better systemic and local therapy is needed for the recurrent soft-tissue sarcomas and the aggressive unclassified sarcomas. Chest-wall resection continues to play a primary role in the management of locally and regionally recurrent breast cancer but is best combined with systemic chemotherapy. Chest-wall resection can provide a long disease-free survival in patients with isolated metastases from sarcomas or carcinomas. In addition, significant palliation can be afforded patients with symptomatic chest-wall metastases and a shortened life expectancy.

Antineoplastic Agents↗

Intradermal transplantation in mice of small numbers of sarcoma cells followed by tumor growth and regression.

Relatively small numbers of Sarcoma 1 cells were transplanted intradermally in A/WySn mice to study the course of growth when the size of the transplant is comparable to an early stage of spontaneous cancer. Transplants of 31 to 32,000 cells took one of three courses: no apparent growth; development of tumor followed by regression; or progressive growth. Transplants of 8,000 cells were the most evenly divided among these three courses and were selected for further study. Bilateral tumors took the same course to regression or to continued growth with significant frequency. There was complete correlation between regression of a tumor and immunity to a challenge made 1 to 5 weeks after the original transplant. Persistent tumors had a similar relationship, but the immunity was less complete. Limited, inapparent growth, followed by regression, was indicated in some mice, simulating immunological surveillance. Serum from such mice, when administered systemically in other mice, apparently induced enhancement of intradermal transplants.

Animals↗

Diagnosis and differential diagnosis of small-cell lesions of the liver.

The objective of this study was to evaluate the cytologic spectrum of small cell lesions of liver as diagnosed by fine-needle aspiration (FNA). Of 304 FNAs of liver that were performed in our institution between 1990 and 1994, 29 were classified as small-cell lesions. The final diagnoses were as follows: small-cell undifferentiated carcinoma (10), neuroendocrine carcinoma (9), cloacogenic carcinoma (1), Merkel-cell carcinoma (1), cholangiocarcinoma (1), metastatic adenocarcinoma (4), small-cell sarcoma (1), lymphoma (2). Relevant clinical history and immunocytochemistry were helpful in making the final diagnosis in some cases. The diagnosis and differential diagnosis of small cell lesions of the liver are discussed in detail in this report.

Adenocarcinoma↗

Antigenicity of fusion proteins from sarcoma-associated chromosomal translocations.

Synovial sarcoma (SS), clear cell sarcoma (CCS), and desmoplastic small round cell tumor (DSRCT) are soft-tissue malignancies occurring primarily in adolescents and young adults. These tumors contain specific chromosomal translocations that fuse the 5' region of one gene with the 3' region of another, resulting in the formation of characteristic fusion proteins. These translocations are unique to tumor cells and may be required for persistence, thereby serving as targets for immunotherapy. It was hypothesized that the fusion breakpoint sequences associated with SS, CCS, and DSRCT can serve as tumor-specific neoantigens. To test this, peptides corresponding to the fusion breakpoints were designed and assessed for ability to bind to various class I HLA molecules. Two peptides derived from the SS breakpoint specifically bind the HLA-B7 antigen, and a 10-amino acid minimal epitope was identified for this interaction. Specific binding of a SS peptide and a CCS peptide to HLA-B27 molecule was also observed. Finally, a peptide designed from the DSRCT breakpoint specifically binds the HLA-A3 molecule, and a 9-amino acid optimal epitope was identified for this interaction. The physiological/immunological relevance of these peptide/MHC interactions was demonstrated by the induction of SS-specific CTLs from normal donor lymphocytes using in vitro stimulation with autologous, peptide-pulsed dendritic cells and by the ability of these CTLs to lyse human SS tumor cells endogenously expressing the full-length fusion protein. These results suggest that sequences in the fusion region of sarcoma-associated chimeras can bind class I HLA molecules and serve as neoantigens. These may be useful for the development of novel immunotherapies for sarcoma patients with appropriate HLA molecules and tumors bearing these translocations.

Amino Acid Sequence↗

Clear cell sarcoma of the small bowel: a potential pitfall. Case report.

Clear cell sarcoma (soft-part melanoma) is a very rare entity with a distinctive histopathologic and molecular profile. Herein, we present the sixth reported case of a primary gastrointestinal clear cell sarcoma discovered in a 21-year-old woman. The patient underwent numerous tests prior to the diagnosis of her small bowel pathology, including the use of capsule endoscopy, which allowed for visualization and final localization of the tumour. Additionally, we discuss this rare type of sarcoma that affects young adults and has a poor prognosis characterized by the balanced chromosomal translocation t(12;22)(q13;q12) with special emphasis on the necessity for pathologists to be able to distinguish it from melanoma -- potentially a major pitfall in diagnosis.

Adult↗

Atypical primitive neuroectodermal tumors. Comparative light and electron microscopic and immunohistochemical studies on peripheral neuroepitheliomas and Ewing's sarcomas.

Recently, primitive neuroectodermal tumors (PNETs) have been shown to cover a wide spectrum of small round cell sarcomas, probably including some Ewing's sarcomas (ESs) and extraskeletal Ewing's sarcomas (EESs), in addition to classical peripheral neuroepitheliomas (PNs). In studies of small cell sarcomas, we found a group of undifferentiated tumors resembling PNETs with some features of neuroectodermal differentiation, but possessing areas of relatively large, pleomorphic cells. To clarify the nature of these tumors and their relationship to PNETs, we examined the variety of histological, immunohistochemical and ultrastructural features of 11 small cell sarcomas. Five of these tumors were composed of uniform, small round cells and were classified as PNs because of the presence of definite Homer-Wright rosettes and fibrillary processes. The presence of well developed neurite-like processes containing neurosecretory granules and immunoreactivities for various neural markers suggested that these PNs showed more advanced neuronal differentiation. Two tumors, with the classical features of ES, showed no ultrastructural evidence of neuronal differentiation, although only gamma-gamma neuron-specific enolase (NSE) positivity was detected. Four undifferentiated tumors with atypical features, included in this study as an atypical PNET group, showed certain neuroectodermal characteristics, such as ganglion cell differentiation, perivascular pseudorosettes, and gamma-gamma NSE reactivity. It is concluded from this study that PNETs may include small round cell tumors showing different degrees of neuro-ectodermal differentiation and some histological variations.

Adolescent↗

Peripheral neuroectodermal sarcoma of soft tissue (peripheral neuroepithelioma): a pathologic study of ten cases with differential diagnosis regarding other small, round-cell sarcomas.

Peripheral neuroepithelioma of soft tissue belongs to the group of peripheral neuroectodermal tumors (PNETs), but because of its clinical, biological, and morphological characteristics, it differs from other small, round-cell sarcomas that appear in children (neuroblastoma) or in the thoracopulmonary region (Askin's tumor) and bone (peripheral neuroectodermal sarcoma of bone). We report ten new cases of such PNET variety, based on their histologic, immunohistochemical, and electron microscopic findings. In all of these cases, the clinicopathologic correlations demonstrated high malignancy, with an ominous outcome in nine cases. The mean age of the patients was 32.6 years and there was a clear male predominance (eight men, two women). Histologically, the presence of Homer-Wright rosettes is mandatory for diagnosis, being complemented with positive immunohistochemistry for several neural immunomarkers using paraffin-embedded material. Neuron-specific enolase, E-36, HNK-1, and chromogranin neural markers proved to be positive in a high number of cases, but other markers (S-100 protein, synapto-physin, GFA protein, and neurofilaments [70 kilodalton]) were absent. Electron microscopy confirmed the presence of neural structures, both by scanning and transmission electron microscopy.

Adolescent↗

Fine-needle aspiration biopsy of soft tissue sarcomas. A cytomorphologic analysis with emphasis on histologic subtyping, grading, and therapeutic significance.

Because therapy for sarcoma often incorporates histologic subtype, grade, stage, and anatomic location, establishing a specific histologic subtype often is essential. To evaluate the effectiveness of fine-needle aspiration biopsy (FNAB) in histologic subtyping of soft tissue sarcomas, we retrospectively reviewed 73 consecutive aspirates from 67 patients, none of whom had a previously established sarcoma diagnosis. Sarcoma cases were subgrouped according to predominant cytomorphologic features: pleomorphic cell, 19; small round cell, 18; spindle cell, 18; myxoid, 10; epithelioid/polygonal cell, 7; 1 case of well-differentiated liposarcoma was analyzed separately. Ancillary studies were used for 25 cases. Among adequate specimens, 61 tumors were recognized as sarcoma. A specific and accurate histologic subtype was determined in 34 cases. Ancillary studies were most useful for histologic subtyping of small round cell and spindle cell sarcomas. Myxoid sarcomas were subtyped easily based solely on histomorphologic features. Pleomorphic cell and epithelioid/polygonal cell sarcomas were recognized easily as malignant but difficult to subtype by FNAB. With the exception of small round cell sarcomas, histologic subtyping of a sarcoma usually did not directly influence therapy. With meticulous attention to clinicopathologic features and ancillary techniques, many sarcomas, especially small round cell, spindle cell, and myxoid types, may be subtyped successfully by FNAB, within limitations.

Adolescent↗

Relationship between histologic grade and cytofluorometric cellular DNA and RNA content in primary bone tumors.

The diagnosis and grading of bone tumors remains a challenging problem. We studied the relationship between histologic grade and cytofluorometric cellular DNA and RNA content in 108 primary bone tumors. The data included DNA ploidy, mean DNA content (MDC), S-phase fraction (SPF), mean RNA content (MRC) and RNA/DNA ratio (RDR; MRC/MDC) which represents the RNA content normalized for the DNA content. Benign tumors had a diploid stem line with low MDC (mean; 1.04), low SPF (0.9), high MRC (2.41) and high RDR (2.31). Giant cell tumors of bone, which are locally aggressive benign tumors, showed diploidy with relatively higher MDC (1.07, p < 0.01) and SPF (2.6, p < 0.01) and lower MRC (1.81, p < 0.01) and RDR (1.69, p < 0.01). Similar results were obtained in low-grade sarcomas. In high-grade sarcomas, the data depended on the histologic findings. Pleomorphic sarcomas such as osteosarcomas revealed aneuploidy with remarkably higher MDC (1.70 in osteosarcomas, p < 0.01) and SPF (6.5, p < 0.01), but lower RDR (1.70, p < 0.01). In contrast, small cell sarcomas, such as Ewing's sarcomas, showed diploidy with low MDC (1.11 in Ewing's sarcomas, N.S.) and SPF (2.5, p < 0.01) and extremely low RDR (1.34, p < 0.01). The RDR value was higher in well-differentiated tumors than in primitive tumors, rendering it useful in grading bone tumors with a diploid stem line. By combining the RDR value with the MDC value, 96% of diploid sarcomas could be distinguished from benign tumors. These results indicate that cellular DNA and RNA content analysis may be of value in assessing the malignant potential of diploid as well as aneuploid bone sarcomas.

Bone Neoplasms↗

Establishment and characterization of a clonal human extraskeletal Ewing's sarcoma cell line, EES1.

Ewing's sarcoma, a small round cell sarcoma arising in soft tissue as well as the bone, is one of the most malignant tumors in children and young adults. Few established cell lines of extraskeletal Ewing's sarcoma (EES) have been reported, which made it difficult to examine the biological features of EES. Therefore, we have established a new clonal cell line of EES. We report its morphological characters, results of chromosomal and immunohistochemical analysis. A piece of tumor obtained from the 18-year-old female patient with EES was xenografted in a nude mouse. In vitro subcultured cells were then obtained from this xenograft. A clonal cell line was subsequently established by limiting dilution and designated EES1. EES1 cells had a doubling time of 24 hours. In the xenografted tumor, the cells expressed vimentin, CD99 (MIC2), neuron specific enolase (NSE) and cytokeratin. The original tumor cells also expressed vimentin, CD 99, and NSE, but was negative for cytokeratin. The morphological and immunohistochemical features of this cell line established, except for cytokeratin expression, were consistent with those of the primary tumor. Cytogenetic analysis of EES1 revealed chromosomal translocation of t(11; 12)(q24;ql2). The chimeric fusion of the Ewing's sarcoma gene in band 22q12 with the Friend leukemia virus integration-1 gene in band 11q24 was also demonstrated. Fluorescence in situ hybridization further confirmed the presence of translocation involving the Ewing's sarcoma gene in both the primary tumor and EES1 cells. In conclusion, we have established a human EES cell line EES1, which will provide a useful model for studying various aspects of human EES.

Adolescent↗

The retinoblastoma gene: role in cell cycle control and cell differentiation.

The retinoblastoma (RB) gene is the prototype tumor suppressor gene. It encodes a nuclear protein that acts as a cell cycle control checkpoint at the G1 phase. Deletion or inactivation of both RB alleles plays an essential, rate-limiting role in retinoblastoma and in the osteosarcomas that arise within families that carry a mutated RB gene. RB inactivation is also found in other sarcomas, small cell carcinoma of the lung, and in carcinoma of the breast, bladder, and prostate. Transforming proteins encoded by SV40, and the transforming or tumor-associated subtypes of adenoviruses and human papilloma viruses (HPV) can bind RB, thereby blocking its normal function. The EBNA-5 protein of Epstein-Barr virus (EBV) is also able to bind RB in vitro. In addition, RB can interact with several cellular proteins, including the transcription factor E2F. RB gene knock-out mice die in utero around day 14 of gestation. The embryos show disturbed neural and hematopoietic differentiation, indicating that RB is vitally important for these processes. This notion is further supported by studies demonstrating that RB expression in mouse embryo tissues is highest in cells undergoing differentiation, and that RB is required for MyoD-induced muscle differentiation.

Animals↗

Diagnosis and treatment of soft tissue tumors.

In the management of soft-tissue tumors, accurate diagnosis, using a combination of clinical, radiographic, and histological data, is critical in optimizing outcome. Radiographic diagnoses can be useful, but they cannot accurately predict histology or whether a lesion is benign or malignant. Therefore, all soft lumps that persist or grow should be biopsied if possible. Fine-needle aspiration biopsy is useful in differentiating benign from malignant lesions. Core-needle biopsies can yield a histological diagnosis when the sample is sufficiently large. When open biopsy is required, the skin incision must be carefully placed so that the biopsy site can be completely excised if the lesion is subsequently found to be malignant. Excisional biopsy should be used only for small lesions or when the surgeon is confident that the lesion is benign. If, following excision, the lesion is found to be malignant or desmoid, additional surgery with an adequate excision margin should be performed. In the resection of high-grade sarcomas treated by surgery alone or resistant to preoperative adjuvant therapies, a "curative (wide) margin" must be achieved. We occasionally use preoperative radiation with or without hyperthermia for malignant lesions in the vicinity of neurovascular structures where adequate surgical margins are unlikely to be achieved. The use of chemotherapy is justified only in small-cell sarcomas in which metastasis occurs frequently and chemotherapy is known to be effective. For high-grade spindle-cell or pleomorphic sarcomas, the value of adjuvant chemotherapy remains controversial and needs investigation.

Aged↗

Fusion of the EWS1 and WT1 genes as a result of the t(11;22)(p13;q12) translocation in desmoplastic small round cell tumors.

The isolation and molecular analysis of genes which cause and/or predispose to Wilms' tumor have yielded fascinating insights into the role of tissue-specific gene regulation in both development and disease processes. Analysis of the WT1 transcription factor has clearly established its role in Wilms' tumorigenesis and a broader role in both urogenital organogenesis and mesenchymal cell differentiation events. Clearly, loss of function mutations in WT1 is correlated with aberrant function as a regulator of gene expression, ultimately resulting in neoplastic transformation in the developing kidney. A question we have pursued is whether alterations of WT1 structure and/or function can be associated with other types of malignancies, possibly reflecting WT1's broader role in mesenchymal differentiation. To this end, we have analyzed a rare solid tumor designated Intra-Abdominal Desmoplastic Small Round Cell Sarcoma (IADSRCT) which often displays a recurrent chromosomal translocation t(11;22)(p13;q12) involving the WT1 genomic locus. We have shown that the EWS1 gene fron chromosome 22q12 is fused to the WT1 gene in IADSRCT and that a fusion protein is produced which functions as a potent activator of transcription. Our results suggest that WT1 has sustained a gain-of function alteration as a results of this fusion and that the fusion gene functions as a dominant oncogene in this disease. Thus, the WT1 locus may be the target for both gain- and loss-of-function mutations resulting in different disease outcomes. A summary of our ongoing analysis of the EWS-WT1 fusion gene is presented.

Adult↗