Biomedical subjects

J M Woodruff

Publications and source records attributed to J M Woodruff.

At least 37 records · Page 2Linked to original sources

PubMed2000

Specificity of TLS-CHOP rearrangement for classic myxoid/round cell liposarcoma: absence in predominantly myxoid well-differentiated liposarcomas.

Myxoid liposarcoma (LS), the most common subtype of LS, is known to be characterized by the specific t(12;16) resulting in a TLS-CHOP fusion in almost all cases. We wished to address the following questions: (i) Is this genetic hallmark also present in other types of LS with predominant myxoid change? (ii) What is the proportion of cases with the variant EWS-CHOP fusion? (iii) What is the optimal approach for Southern blot detection of TLS breakpoints? We identified 59 LS characterized histologically by >90% myxoid component, in which frozen tissue tumor was available for DNA extraction. These 59 LS with myxoid features were divided into 2 groups: 42 LS with classic myxoid/round cell appearance (myxoid LS) and 17 well-differentiated LS (WDLS) with a predominant (>90%) myxoid component. Within the myxoid LS group, 29 tumors were low grade and 13 high grade (>20% round cell component). Among the 17 predominantly myxoid WDLS, there were 15 low grade and 2 focally high grade tumors. In addition, we selected as control group, 20 LS of other histological types with minimal or no myxoid change (17 WDLS and 3 pleomorphic LS) and 13 myxofibrosarcomas. Southern blot analysis was performed in all cases using a CHOP cDNA probe, and in all CHOP rearranged cases using a TLS cDNA probe. Probe/enzyme combinations for Southern blot analysis were CHOP exon 3-4 cDNA probe with BamHI or SacI, TLS exon 3-6 cDNA probe with BclI. All 42 cases of myxoid LS showed a CHOP rearrangement and 38 of them also had a TLS rearrangement. Among the 4 myxoid LS without Southern blot evidence of TLS rearrangement, 1 showed an EWS-CHOP fusion by Southern blotting and reverse transcriptase-polymerase chain reaction and in another case, reverse transcriptase-polymerase chain reaction detected a TLS-CHOP fusion transcript. None of the predominantly myxoid WDLS and none of the tumors included in the control group showed rearranegements with CHOP probe. In addition, 12 predominantly myxoid WDLS, 10 other LS, and 5 myxofibrosarcoma from the control group were also tested for TLS rearrangement; all were negative. The TLS-CHOP fusion is highly sensitive and specific for the entity of classic myxoid/round cell LS. Other types of LS, even with a predominant myxoid component, lack the TLS-CHOP rearrangement, confirming that they represent a genetically distinct group of LS. The prevalence of the EWS-CHOP variant fusion was approximately 2% in this series. The optimal enzyme for TLS genomic breakpoint detection is BclI.

Blotting, Southern↗

PubMed2000

Surgical management of intra-abdominal desmoid tumours.

BACKGROUND: Intra-abdominal desmoids are uncommon neoplasms. The aggressive nature of these tumours and the potential for major morbidity secondary to resection can present a difficult surgical dilemma. METHODS: Patients with histologically confirmed intra-abdominal desmoid tumours undergoing laparotomy were identified from a prospective database. Clinical features and outcomes in this group were evaluated. RESULTS: The study group comprised 24 patients. Sixteen patients underwent complete resection of the tumour while eight had biopsy only, with or without intestinal bypass. Small intestinal resection was performed in 12 patients, including three who had a near-total enterectomy. Median follow-up was 62 months, with an actuarial overall survival rate of 73 per cent at 10 years. There was no difference in survival rate between completely resected and unresected patients (P = 0.73). There were seven deaths in the entire group, of which four were in those undergoing complete resection. CONCLUSION: Operation can cure patients with intra-abdominal desmoid tumours, but may result in significant morbidity, especially from loss of small intestine. No other therapy is a predictably good alternative to operation but the natural history of desmoids is often characterized by prolonged periods of stability or even regression. A period of watchful waiting, until significant symptoms develop, may be the most appropriate course in patients who risk mesenteric vascular injury or substantial enterectomy with attempts at resection.

Abdominal Neoplasms↗

PubMed2000

Large plaque-type blue nevus with subcutaneous cellular nodules.

Unusual or atypical melanocytic nevi can be confused with malignant melanoma. The authors present two cases of an unusual variant of blue nevus that were misdiagnosed initially as malignancy. Both lesions were asymptomatic and characterized clinically by childhood onset, with slow enlargement during adolescence and subsequent nodule formation. One lesion, which measured 24 cm in greatest dimension, was located on the anterior chest wall of a 53-year-old woman. The other lesion, which measured approximately 15 cm in greatest dimension, was located on the lateral abdominal wall of a 20-year-old man. Both lesions were characterized by a multifocal dermal and subcutaneous proliferation of fusiform and dendritic pigmented melanocytes. The histologic appearance of individual foci ranged from dermal melanocytosis to common blue nevus and cellular blue nevus. The cellular foci were located in the subcutis and involved, in one patient, the stroma of the breast. The cells were immunoreactive for S-100 protein, gp100 (HMB-45), and Melan-A (A103). Ultrastructural analysis revealed melanocytes typical of blue nevus. The woman underwent complete excision of the lesion, and the man underwent only partial excision of the lesion. On clinical follow-up of 32 and 19 months, respectively, both patients are alive and well with no evidence of recurrence or progression. Because the lesions presented clinically as large plaques and were diagnosed histologically as blue nevi with subcutaneous foci of cellular blue nevus, we term this rare variant of blue nevus large plaque-type blue nevus with subcutaneous cellular nodules. Recognition of this lesion enhances our knowledge of the morphologic spectrum of melanocytic tumors and helps to avoid confusion with malignant melanoma.

Abdominal Muscles↗

PubMed2000

Two hundred gastrointestinal stromal tumors: recurrence patterns and prognostic factors for survival.

OBJECTIVE: To analyze the outcome of 200 patients with gastrointestinal stromal tumor (GIST) who were treated at a single institution and followed up prospectively. SUMMARY BACKGROUND DATA: A GIST is a visceral sarcoma that arises from the gastrointestinal tract. Surgical resection is the mainstay of treatment because adjuvant therapy is unproven. METHODS: Two hundred patients with malignant GIST were admitted and treated at Memorial Hospital during the past 16 years. Patient, tumor, and treatment variables were analyzed to identify patterns of tumor recurrence and factors that predict survival. RESULTS: Of the 200 patients, 46% had primary disease without metastasis, 47% had metastasis, and 7% had isolated local recurrence. In patients with primary disease who underwent complete resection of gross disease (n = 80), the 5-year actuarial survival rate was 54%, and survival was predicted by tumor size but not microscopic margins of resection. Recurrence of disease after resection was predominantly intraabdominal and involved the original tumor site, peritoneum, and liver. CONCLUSIONS: GISTs are uncommon sarcomas. Tumor size predicts disease-specific survival in patients with primary disease who undergo complete gross resection. Tumor recurrence tends to be intraabdominal. Investigational protocols are indicated to reduce the rate of recurrence after resection and to improve the outcome for patients with GIST.

Actuarial Analysis↗

PubMed2000

Effect of reresection in extremity soft tissue sarcoma.

OBJECTIVE: To determine whether reresection affects survival in patients with inadequately resected, primary extremity soft tissue sarcoma. This study correlates reresection with local recurrence-free survival, metastasis-free survival, and disease-free survival. SUMMARY BACKGROUND DATA: Soft tissue sarcomas are rare neoplasms, with an incidence of approximately 6,000 per year in the United States. Because these tumors are rare and benign soft tissue tumors are common, many are initially thought to be benign and are excised without wide margins. METHODS: Patients who underwent treatment for primary tumors from July 1982 to June 1999 at a single institution were the subject of study. Two groups of patients were analyzed: those who underwent one definitive resection (one operation) and those whose tumors were previously resected and who were then referred for subsequent reresection (two operations). Patients were given adjuvant radiation or chemotherapy according to the standard of care. RESULTS: Of 1,092 patients with primary extremity soft tissue sarcoma underwent resection, 685 underwent definitive radical resection and 407 underwent reresection after undergoing excisional resection elsewhere. Median follow-up was 4.8 years. The 5-year disease-free survival rate of the definitive resection (one operation) group was 70%; that of the reresection (two operations) group was 88%. On multivariate analysis, reresection was adjusted and controlled for age, grade, depth, size, histology, and margins. Reresection remained a significant predictor of improved disease-free survival, even after these adjustments. To determine whether this difference was stage- or referral-biased, the patient population was divided by AJCC stage. In all stages there was a trend toward improved outcome; this was most marked for those with stage III disease (>5 cm, high-grade, and deep). CONCLUSIONS: Patients with extremity soft tissue sarcoma who undergo reresection with two "primary" operations have an improved survival compared with those who undergo one operation. The most plausible explanation, referral and selection bias, is questionable given the significance of reresection as a variable after adjusting for stage and other risk factors. This suggests that where indicated and possible, reresection should be liberally applied in patients with primary extremity soft tissue sarcoma.

Actuarial Analysis↗

PubMed2000

Strong association of SYT-SSX fusion type and morphologic epithelial differentiation in synovial sarcoma.

Synovial sarcoma is characterized by a specific recurrent translocation t(X; 18), resulting in either the SYT-SSX1 or SYT-SSX2 gene fusion. Because this is the primary genetic alteration in these tumors, we sought to identify the impact of molecular heterogeneity of the t(X;18) on cell proliferation, apoptosis, and epithelial differentiation in synovial sarcoma. Seventy-three patients with synovial sarcoma (18 biphasic, 55 monophasic) were selected on the basis of availability of tumor material for molecular and immunohistochemical analysis. Tumors were classified as biphasic on the basis of morphologic glandular differentiation. SYT-SSX fusion transcripts were examined by reverse transcriptase polymerase chain reaction using tumor RNA extracted from frozen or paraffin-embedded tissue. Cell proliferation was assessed immunohistochemically by the Ki-67 labeling index. Apoptosis was analyzed immunohistochemically with BAX and BCL2 antibodies and by the TUNEL method. Immunohistochemical evidence of epithelial differentiation was assessed using antibodies to cytokeratins and epithelial membrane antigen. Approximately two thirds of the tumors had an SYT-SSX1 and one third had an SYT-SSX2 fusion transcript. There was a strong association between SYT-SSX fusion type and histologic subtype. All biphasic synovial sarcomas had the SYT-SSX1 fusion, whereas all tumors with SYT-SSX2 were of monophasic morphology. There was, however, no association between SYT-SSX fusion type and expression of cytokeratins and epithelial membrane antigen among monophasic tumors. Tumors with SYT-SSX2 had a significantly higher mean and median Ki-67 labeling index than those with SYT-SSX1, but a comparison of Ki-67 according to fusion type, histologic type, and sample source suggested that the main determinants of proliferation rate were the latter two factors. Specifically, monophasic tumors and metastatic tumors showed significantly higher Ki-67 scores. Apoptosis (by TUNEL) was rarely observed, consistent with prominent expression of the anti-apoptotic protein BCL2 in almost all cases. TUNEL, BCL2, and BAX results did not correlate with SYT-SSX fusion type. These data confirm the strong association of SYT-SSX fusion transcript type with morphologic but not immunophenotypic epithelial differentiation in synovial sarcoma.

Apoptosis↗

PubMed2000

Synovial sarcoma: a multivariate analysis of prognostic factors in 112 patients with primary localized tumors of the extremity.

PURPOSE: Synovial sarcoma is a high-grade tumor that is associated with poor prognosis. Previous studies analyzing prognostic factors are limited because of inclusion of heterogeneous cohorts of patients with nonextremity and recurrent tumors. The objective of this study was to determine independent prognostic factors of primary synovial sarcoma localized to the extremity. PATIENTS AND METHODS: Between July 1, 1982, and June 30, 1996, 112 patients underwent surgical resection for cure at our institution and then were followed-up prospectively. Clinical and pathologic factors examined for prognostic value included age, sex, tumor site and location, depth, size, microscopic status of surgical margins, invasion of bone or neurovascular structures, and monophasic or biphasic histology. The end points analyzed were the time to first local recurrence that was not preceded by a distant recurrence, time to any distant recurrence, and time to disease-related mortality. These end points were modeled using the method of Kaplan and Meier and analyzed by the log-rank test and Cox regression. RESULTS: The median duration of follow-up among survivors in this cohort of 112 patients was 72 months. The 5-year local-recurrence, distant-recurrence, and mortality rates were 12%, 39%, and 25%, respectively. Tumor size > or = 5 cm (P =.001; relative risk [RR] = 2. 7; 95% confidence interval [CI], 1.5 to 5.2) and the presence of bone or neurovascular invasion (P =.04; RR = 2.3; 95% CI, 1.0 to 5. 3) were independent adverse predictors of distant recurrence. Tumor size > or= 5 cm (P =.003; RR = 2.3; 95% CI, 1.4 to 6.3) and the presence of bone or neurovascular invasion (P =.03; RR = 2.7; 95% CI, 1.0 to 6.5) were also independent adverse predictors of mortality. CONCLUSION: The natural history of primary synovial sarcoma of the extremity is related to tumor size and invasion of bone and neurovascular structures.

Adolescent↗

PubMed2000

Monoclonality of multifocal myxoid liposarcoma: confirmation by analysis of TLS-CHOP or EWS-CHOP rearrangements.

Multifocal presentation, defined as the presence of tumor at two or more anatomically separate sites, before the manifestation of disease in sites where sarcomas usually metastasize (e.g., lungs) occurs in about 1% of extremity soft tissue sarcomas (STSs). Debate still persists whether multifocal STSs represent an unusual pattern of metastasis or multiple separate primary tumors. Among STSs with multifocal presentation, myxoid liposarcoma is the predominant histological type. This subtype of liposarcoma contains the specific t(12;16) chromosomal translocation, which results in rearrangement of the TLS and CHOP genes that is clone specific at the DNA level. We, therefore, sought to address the question of clonality by molecular analysis in six patients who presented with either synchronous or metachronous multifocal myxoid liposarcoma. In all six cases, adequate frozen tumor was available for DNA extraction from at least two distinct anatomical sites. Southern blot analysis using CHOP, TLS, and EWS cDNA probes was performed on genomic DNA. Five cases contained a TLS-CHOP rearrangement, and one case had the variant EWS-CHOP fusion (seen in <5% of cases). The size of the rearranged CHOP fragment differed among the six patients, as expected, but was identical in all anatomically separate tumor samples from each patient. Likewise, the sizes of the rearranged bands observed with either the TLS or EWS probes supported the monoclonality of all cases. Our results confirm the monoclonal origin of multifocal myxoid liposarcoma, establishing the metastatic nature of distant soft tissue lesions in these cases. It remains unclear whether this unusual pattern of metastasis represents an intrinsic property of this subset of myxoid liposarcoma or merely a rare chance occurrence. The clinical outcomes observed in this small series suggest that the prognosis of multifocal myxoid liposarcoma is poor, regardless of its often bland or "low-grade" histological appearance.

Adult↗

PubMed1999

Extremity and trunk desmoid tumors: a multifactorial analysis of outcome.

BACKGROUND: The natural history of desmoid tumors remains an enigma. Previous reports attempting to identify their biology have included recurrent and primary tumors as well as tumors from both intra- and extra-abdominal sites. The purpose of this study was to analyze patients with primary extremity and trunk desmoid tumors treated and followed at a single institution and to determine factors influencing disease free survival. METHODS: Between July 1982 and June 1997, 189 patients with extremity and superficial trunk desmoid tumors were treated and followed prospectively. Of these, 105 presented with primary disease and formed the basis of this study. RESULTS: The median follow-up for the entire group of patients was 49 months; it was 46 months for patients who did not develop a local recurrence. During this time, 24 patients (23%) had a local recurrence. No patients died of disease. The 2-year and 5-year local recurrence free survival rates were 80% and 75%, respectively. None of the prognostic factors analyzed, including age, gender, depth of tumor, size of tumor, or tumor site, were significant for predicting local recurrence. Moreover, positive resection margins were not predictive of recurrence. The selective use of adjuvant radiation therapy did not influence the rate of local recurrence regardless of the margin status. CONCLUSIONS: Attempts to achieve negative resection margins may result in unnecessary morbidity and may not prevent local recurrence. Operations that preserve function and structure should be the primary goal, because the presence of residual disease cannot be clearly shown to impact adversely on 5-year disease free or overall survival.

Adult↗

PubMed1999

Schwann cell hyperplasia and tumors in transgenic mice expressing a naturally occurring mutant NF2 protein.

Specific mutations in some tumor suppressor genes such as p53 can act in a dominant fashion. We tested whether this mechanism may also apply for the neurofibromatosis type-2 gene (NF2) which, when mutated, leads to schwannoma development. Transgenic mice were generated that express, in Schwann cells, mutant NF2 proteins prototypic of natural mutants observed in humans. Mice expressing a NF2 protein with an interstitial deletion in the amino-terminal domain showed high prevalence of Schwann cell-derived tumors and Schwann cell hyperplasia, whereas those expressing a carboxy-terminally truncated protein were normal. Our results indicate that a subset of mutant NF2 alleles observed in patients may encode products with dominant properties when overexpressed in specific cell lineages.

Animals↗

PubMed1999

Malignant fibrous histiocytoma of the extremity.

BACKGROUND: This study examines prognostic factors and outcomes for a group of patients with malignant fibrous histiocytoma of the extremity treated at a single referral institution. METHODS: A total of 239 patients underwent complete surgical excision between July 1982 and July 1996 and were followed prospectively. RESULTS: The overall 5-year and 10-year disease specific survival rates for this group were 65% and 59%, respectively. Age >50 years, tumor location, and presentation with local recurrence were all associated with increased risk of local recurrence. Tumor size, grade, depth, and presentation with local recurrence were all associated with adverse disease specific and metastasis free survival. Tumor size > or = 10 cm was associated with a particularly unfavorable outcome. CONCLUSIONS: The majority of malignant fibrous histiocytomas of the extremity are associated with a relatively favorable prognosis. Size > or = 5 cm, deep depth, and high grade are all unfavorable factors. Size > or = 10 cm is associated with an even more unfavorable prognosis.

Adolescent↗

PubMed1999

Pathology of tumors of the peripheral nerve sheath in type 1 neurofibromatosis.

The two main peripheral nerve sheath tumors found in patients with neurofibromatosis, type 1 (NF1), are neurofibroma, a benign tumor, and malignant peripheral nerve sheath tumor (MPNST). The tumors are related in that most MPNSTs are thought to arise by malignant transformation of neurofibromas. Such an event occurs in about 2% of NF1 patients. There are five forms of neurofibroma; three of them-localized cutaneous neurofibroma when multiple, plexiform neurofibroma, and massive soft-tissue neurofibroma-are highly specific for NF1. Only two forms of neurofibroma, plexiform and localized intraneural neurofibroma, are significant precursors of MPNST. Massive soft-tissue neurofibromas are worrisome in that they may mask MPNST arising from one of the mentioned neurofibromas. The vast majority of MPNSTs are high-grade malignant tumors with a high rate of distant metastasis. The overall 5-year survival rate for patients with MPNSTs ranges from 34% to 52%. MPNSTs generally are solitary, deep-seated globoid or fusiform tumors. They are firm, fleshy, tan, and often focally to extensively necrotic, and they invade surrounding soft tissue. On histological examination, MPNSTs are most often hypercellular, hyperchromatic, fasciculated, and mitotically active tumors. Low-grade tumors account for only about 10-15% of cases. Twenty percent of MPNSTs have unusual and potentially misleading histological features, such as epithelioid cells and divergent mesenchymal or glandular differentiation. Am. J. Med. Genet. (Semin. Med. Genet.) 89:23-30, 1999.

Humans↗

PubMed1999

Multifactorial analysis of the survival of patients with distant metastasis arising from primary extremity sarcoma.

BACKGROUND: Despite optimal multimodality limb-sparing therapy for extremity soft tissue sarcoma (STS), a significant number of patients develop distant metastasis. The objective of this study was to analyze patterns of metastatic disease and define prognostic factors for survival in a large group of patients followed prospectively at a single institution. METHODS: Between July 1, 1982, and June 30, 1996, all adult patients admitted to the Memorial Sloan-Kettering Cancer Center with primary extremity sarcoma were treated and prospectively followed. Patients who developed distant metastases constituted the study group. Prognostic factors were analyzed for postmetastasis survival. These included both factors related to the primary tumor and factors related to the pattern of metastasis. Postmetastasis survival was modeled using the Kaplan-Meier method. Statistical significance was evaluated using the log rank test for univariate analysis and the Cox proportional hazards model for multivariate analysis. RESULTS: During the study period, the authors admitted and treated 994 patients with primary extremity STS. The median follow-up was 33 months. Distant metastasis developed in 230 patients (23%). Median survival after distant metastasis was 11.6 months. The lungs were the first metastatic site in 169 patients (73%). Other first sites of metastasis included the skin and soft tissues of the head and neck, trunk, and extremities. There was no statistically significant difference in survival between patients with pulmonary and those with nonpulmonary metastatic disease. In multivariate analysis, resection of metastatic disease, the length of the disease free interval, the presence of a preceding local recurrence, and patient age > 50 years all were significant predictors of postmetastasis survival. Other factors that defined the primary tumor, including histologic grade, depth, and microscopic margins, were not associated with postmetastasis survival. CONCLUSIONS: Despite optimal multimodality therapy, 23% of the patients in this series with primary extremity sarcoma developed distant metastasis. Median survival after metastasis was approximately 1 year. After metastasis, the independent favorable factors that are associated with patient survival include resection of the metastases, a long disease free interval, the absence of preceding local recurrence, and patient age < 50 years. Although a definitive conclusion regarding the benefit of resection can be made only with a randomized clinical trial, these data suggest that resection of metastatic STS may contribute to patient survival, which in some cases may be long term.

Adolescent↗

PubMed1999

Alterations of INK4A and INK4B genes in adult soft tissue sarcomas: effect on survival.

BACKGROUND: The INK4A and INK4B genes map to chromosome 9p21, with the INK4A gene encoding two protein products, p16 and pl9ARF. Alterations of the INK4A and INK4B genes occur frequently in certain primary malignant neoplasms. This study was undertaken to evaluate the frequency of INK4A and INK4B gene alterations in a cohort of adult soft tissue sarcomas. METHODS: The status of the INK4A and INK4B genes was determined in 46 soft tissue sarcomas by use of the following methods: Southern blotting, polymerase chain reaction (PCR), single-strand conformation polymorphism analysis, comparative multiplex PCR, and a methylation assay focusing on the p16 promoter. Associations between alterations of the INK4A and INK4B genes and clinicopathologic variables, as well as with p53 and pRB (retinoblastoma protein) status, were evaluated by use of the two-tailed Fisher's exact test. Disease-specific survival was evaluated by use of the Kaplan-Meier method and the logrank test. Proportional hazards analysis was used to obtain estimates of relative risks. All P values are two-sided. RESULTS: Homozygous and hemizygous deletions, but no point mutations, were observed in these two genes. The overall frequency of gene alteration (deletion or rearrangement) was approximately 15% for the INK4A and INK4B genes, with changes restricted to high-grade sarcomas. Statistically significant associations were observed between INK4A/INK4B deletions (P = .036) or alterations (P = .005) and poor survival. Alteration of the INK4A and INK4B genes was the only statistically significant predictor for poor survival when controlling for tumor grade and size (P = .03). CONCLUSION/IMPLICATIONS: Coincident homozygous deletion of the INK4A and INK4B genes occurs frequently in adult soft tissue sarcomas. Loss of p16 and pl9ARF function in primary tumors, although not equivalent to alterations in p53 and pRB function, appears to be associated with cancers that have an aggressive biologic behavior.

Adult↗

PubMed1999

Colonic manifestations of multiple endocrine neoplasia type 2B: report of four cases.

Multiple endocrine neoplasia type 2B is best known for its endocrine manifestations and typical phenotype. The gastrointestinal manifestations, however, are also an important and commonly unrecognized component of the syndrome. We present four cases that demonstrate the varied presentation of patients with colonic manifestations of multiple endocrine neoplasia type 2B. We discuss the cause, diagnostic significance, and management of the colonic disease that is a component of multiple endocrine neoplasia type 2B.

Adolescent↗

PubMed1999

Deletions of the INK4A gene occur in malignant peripheral nerve sheath tumors but not in neurofibromas.

The INK4A gene, a candidate tumor suppressor gene located on chromosome 9p21, encodes two protein products, p16 and p19(ARF). p16 is a negative cell cycle regulator capable of arresting cells in the G1 phase by inhibiting cyclin-dependent kinases 4 (Cdk4) and 6 (Cdk6), thus preventing pRB phosphorylation. p19(ARF) prevents Mdm2-mediated neutralization of p53. Loss of INK4A is a frequent molecular alteration involved in the genesis of several neoplasms, including tumors of neuroectodermal origin. This study investigated the frequency of INK4A gene alterations in a series of malignant peripheral nerve sheath tumors (MPNSTs) and neurofibromas (NFs). INK4A gene and the p19(ARF)-specific exon 1beta were studied in 11 MPNST samples from 8 patients and 7 neurofibromas. Presence of INK4A deletions was assessed by Southern blotting hybridization and by a multiplex polymerase chain reaction (mPCR). INK4A point mutations were examined by single-strand conformation polymorphism (SSCP) and sequencing. The p16 promoter methylation status was determined by PCR amplification of bisulfite-treated DNA. Homozygous deletions of exon 2, thus affecting both p16 and p19(ARF), were identified in MPNSTs from 4 of 8 patients. Deletions, mutations, or silencing by methylation were not identified in the neurofibromas analyzed. Based on our results, we conclude that INK4A deletions are frequent events in MPNSTs and may participate in tumor progression. Silencing of p16 by methylation, which occurs often in several tumor types, is uncommon in MPNSTs.

Blotting, Southern↗

PubMed1999

Expression of p27(kip) and other cell cycle regulators in malignant peripheral nerve sheath tumors and neurofibromas: the emerging role of p27(kip) in malignant transformation of neurofibromas.

There is little information regarding the status of cell cycle regulators in malignant peripheral nerve sheath tumors (MPNSTs) and neurofibromas (NFs). In this study, we investigated patterns of expression of p53 and pRB, cyclin-dependent kinase inhibitors (CKIs) p21 and p27, as well as cyclins D1 and E, in a cohort of 35 well-characterized MPNSTs and 16 NFs. These phenotypes were correlated with proliferative index, as assessed by Ki-67, as well as clinicopathological parameters of poor outcome. p53 nuclear overexpression was found in 10 of 35 (29%) MPNSTs, and it was lacking in NFs (P = 0.02). There were no differences in the patterns of expression of pRB, cyclin D1, and p21 between MPNSTs and NFs. However, p27 nuclear expression was present in most NFs, but it was absent in the majority of MPNSTs, which displayed cytoplasmic staining (P < 0.001). Nuclear cyclin E expression was more pronounced in MPNSTs than in NFs. We observed inverse patterns of expression for nuclear p27 and nuclear cyclin E expression. The staining profiles of cytoplasmic p27 and nuclear cyclin E expression were found to be statistically associated (P = 0.01). High Ki-67 expression was found in 20 of 34 (59%) MPNSTs but was absent in NFs (P < 0.001). Furthermore, detection of cytoplasmic p27 expression was found to be a prognostic factor for poor survival in MPNSTs (P = 0.03, relative risk = 2.4).

Cell Cycle↗

PubMed1999

Low-grade fibrosarcoma with palisaded granulomalike bodies (giant rosettes): report of a case that metastasized.

"Hyalinizing spindle cell tumor with giant rosettes" is a tumor recently described by Lane et al. and thought by them possibly to represent a form of low-grade fibromyxoid sarcoma. Proof of a metastatic potential was lacking. We report an example of this tumor on the arm of a 28-year-old woman. The ultrastructural study of the tumor confirmed the fibroblastic nature of the lesion, which subsequently metastasized to the lung. Histologically, the giant rosettes simulated palisaded granulomas. Our findings warrant classifying the tumor as a sarcoma, and we suggest the designation low-grade fibrosarcoma with palisaded granulomalike bodies (giant rosettes).

Adult↗