Fibromatosis of the breast and mutations involving the APC/beta-catenin pathway

Bilateral breast fibromatosis: case report and review of the literature

Fibromatosis or desmoid tumor is a benign, slow-growing fibroblastic neoplasm originating from musculoaponeurotic stromal elements. These tumors are characterized by an infiltrative and locally aggressive growth pattern, frequent recurrences, but no metastatic potential. The etiology is unknown, but these tumors have been associated with trauma and genetic disorders. Breast fibromatosis is exceedingly rare and often misdiagnosed, comprising only 0.2% of breast tumors. Clinically, it might mimic other breast lesions, such as carcinoma. Only approximately 6 case series and 100 case reports of this disorder affecting the breast are documented, and only 5 cases of bilateral breast fibromatosis have been reported. We describe the case of a 20-year-old woman who presented to our institution with firm, nontender masses palpable in both breasts. Prior ultrasound was suspicious for carcinoma, and breast core biopsies were suggestive of phyllodes tumor. An excisional biopsy was necessary to establish the diagnosis of breast fibromatosis for both masses. A review of articles published on desmoid tumors and breast fibromatosis was performed with emphasis on articles published in the last 10 years. Fibromatosis should be considered in the differential diagnosis of patients presenting with hard breast lumps suspicious of other diseases.

Desmoid tumors of the bilateral breasts in a patient without Gardner syndrome: a case report and review of literature

Desmoid tumors constitute 0.02% to 0.03% of all tumors. Consequently, few case reports exist for breast desmoids, even fewer identifying bilateral disease. We present a case report of a patient with bilateral breast desmoids and shoulder desmoid without evidence of FAP or Gardner syndrome. This case report explores the clinical, radiographic, pathologic, and treatment elements for desmoid tumors as well as a review of the literature.

Stromal deletion of the APC tumor suppressor in mice triggers development of endometrial cancer

The contribution of the stromal microenvironment to the progression of endometrial cancer has not been well explored. We have conditionally expressed a mutant allele of adenomatous polyposis coli (APC(cKO)) in murine uterine stroma cells to study its effect on uterine development and function. In addition to metrorrhagia, the mice develop complex atypical endometrial gland hyperplasia that progresses to endometrial carcinoma in situ and endometrial adenocarcinoma as evidenced by myometrial invasion. Stromal cells subjacent to the carcinoma cells express alpha-smooth muscle actin (αSMA) with fewer cells expressing platelet-derived growth factor α compared with normal stromal cells, suggesting that the mutant stromal cells have acquired a more myofibroblastic phenotype, which have been described as cancer-associated fibroblasts and have been shown to induce carcinogenesis in other organ systems. Analyses of human endometrial cancer specimens showed substantial αSMA expression in the stroma compared with normal endometrial stroma cells. We also show that APC(cKO) mutant uteri and human endometrial cancer have decreased stromal levels of transforming growth factor β and bone morphogenetic protein activities and that the mutant uteri failed to respond to exogenous estradiol stimulation. The mutant stroma cells also had higher levels of vascular endothelial growth factor and stromal derived factor signaling components and diminished expression of estrogen receptor α and progesterone receptor, which is common in advanced stages of human endometrial cancer and is an indicator of poor prognosis. Our results indicate that de novo mutation or loss of heterozygosity in stromal APC is sufficient to induce endometrial hyperplasia and endometrial carcinogenesis by mechanisms that are consistent with unopposed estrogen signaling in the endometrial epithelium.

[Desmoid tumor of the breast in a 9 years old little girl]

Aggressive fibromatosis (desmoid tumour) of the breast is a rare tumour that accounts only for 0.2% of primary breast tumours. This is a benign mesenchymal tumour that develops from muscular fasciae and aponeuroses. It is characterized by its local evolution and its tendency to relapse without metastasizing. Wide radical resection should be attempted whenever possible. Positive margins at resection and reoperation are associated with a high risk of local recurrence. The role of radiotherapy and of medical treatments- especially anti-estrogens - remains unclear. We report here the case of desmoid tumour of the breast arising in a 9-year-old little girl.

β-Catenin pathway activation in breast cancer is associated with triple-negative phenotype but not with CTNNB1 mutation

Aberrant β-catenin expression as determined by assessment of its subcellular localization constitutes a surrogate marker of Wnt signalling pathway activation and has been reported in a subset of breast cancers. The association of β-catenin/Wnt pathway activation with clinical outcome and the mechanisms leading to its activation in breast cancers still remain a matter of controversy. The aims of this study were to address the distribution of β-catenin expression in invasive breast cancers, the correlations between β-catenin expression and clinicopathological features and survival of breast cancer patients, and to determine whether aberrant β-catenin expression is driven by CTNNB1 (β-catenin encoding gene) activating mutations. Immunohistochemistry was performed on a tissue microarray containing 245 invasive breast carcinomas from uniformly treated patients, using two anti-β-catenin monoclonal antibodies. Selected samples were subjected to CTNNB1 exon 3 mutation analysis by direct gene sequencing. A good correlation between the two β-catenin antibodies was observed (Spearman's r >0.62, P<0.001). Respectively, 31 and 11% of the cases displayed lack/reduction of β-catenin membranous expression and nuclear accumulation. Complete lack of β-catenin expression was significantly associated with invasive lobular carcinoma histological type. Subgroup analysis of non-lobular cancers or non-lobular grade 3 carcinomas revealed that lack/reduction of β-catenin membranous expression and/or nuclear accumulation were significantly associated with oestrogen receptor negativity, absence of HER2 gene amplification and overexpression, lack/reduction of E-cadherin expression and tumours of triple-negative and basal-like phenotype. Univariate survival analysis revealed a significant association between β-catenin nuclear expression and shorter metastasis-free and overall survival in the whole cohort; however, β-catenin nuclear expression was not an independent predictor of outcome in multivariate analysis. No CTNNB1 mutations were identified in the 28 selected breast carcinomas analysed. In conclusion, β-catenin/Wnt pathway activation is preferentially found in triple-negative/basal-like breast carcinomas, is associated with poor clinical outcome and is unlikely to be driven by CTNNB1 mutations in breast cancer.

Key signaling nodes in mammary gland development and cancer: β-catenin

β-Catenin plays important roles in mammary development and tumorigenesis through its functions in cell adhesion, signal transduction and regulation of cell-context-specific gene expression. Studies in mice have highlighted the critical role of β-catenin signaling for stem cell biology at multiple stages of mammary development. Deregulated β-catenin signaling disturbs stem and progenitor cell dynamics and induces mammary tumors in mice. Recent data showing deregulated β-catenin signaling in metaplastic and basal-type tumors suggest a similar link to reactivated developmental pathways and human breast cancer. The present review will discuss β-catenin as a central transducer of numerous signaling pathways and its role in mammary development and breast cancer.

β-catenin/Wnt signalling pathway in fibromatosis, metaplastic carcinomas and phyllodes tumours of the breast

Wnt signalling pathway is known to have a critical role in carcinogenesis and in epithelial-to-mesenchymal transition. Upon Wnt activation, β-catenin is translocated from the membrane to the cytoplasm and nucleus, where it interacts with transcriptional activators. It has been suggested that various spindle cell lesions of the breast may harbour Wnt pathway activation. Given that β-catenin nuclear localization constitutes a good surrogate marker of Wnt canonical pathway activation, we have investigated the distribution of β-catenin in spindle cell lesions of the breast and whether it could be employed in the differential diagnosis of these lesions. A total of 52 metaplastic breast carcinomas, eight fibromatoses and 23 phyllodes tumours were retrieved from our institutions' archives. We performed immunohistochemistry using two anti-β-catenin antibodies. In all, three fibromatoses and 21 metaplastic breast carcinomas were subjected to CTNNB1 (β-catenin encoding gene) mutation analysis by direct gene sequencing. A good correlation between the two antibodies was observed (Spearman's r>0.82, P<0.001). All fibromatoses and 23% of metaplastic breast carcinomas expressed nuclear β-catenin. In fibromatosis, β-catenin was more often diffusely expressed, whereas in metaplastic breast carcinomas, expression was more frequently focal. Membranous β-catenin expression was significantly lower in spindle cell carcinomas than in other subtypes of metaplastic breast carcinomas. In phyllodes tumours, stromal cells of benign and malignant subtypes displayed nuclear β-catenin expression in 94 and 57% of cases, respectively. No CTNNB1 mutation was identified in any of the 21 metaplastic carcinomas analysed, whereas the mutations 45S>S/P and 41T>T/A were found in samples of fibromatosis. In conclusion, β-catenin nuclear expression is a common feature in fibromatoses and in the stromal component of phyllodes tumours, but may also be observed in metaplastic breast carcinomas. β-catenin nuclear expression should not be used as a single marker to differentiate fibromatosis from other spindle cell tumours of the breast.

Metachronous multifocal desmoid-type fibromatoses along the neuraxis with adenomatous polyposis syndrome

Desmoid-type fibromatosis, aggressive fibromatosis, or desmoid tumor is an uncommon benign but locally aggressive fibroblastic lesion. Although intraabdominal desmoid-type fibromatoses are well described in association with adenomatous polyposis syndrome, their occurrence along the neuraxis is extremely rare. The authors report the case of a 14-year-old boy with metachronous intracranial and spinal desmoid-type fibromatoses with preceding medulloblastoma. He was ultimately diagnosed with adenomatous polyposis syndrome. This is the first reported case of spinal desmoid-type fibromatosis in association with adenomatous polyposis syndrome. The identification of an underlying genetic instability allows for screening to detect lesions and institute measures to avoid preventable mortality from nonneurological tumors.

Pathogenesis of radiation-induced capsular contracture in tissue expander and implant breast reconstruction

BACKGROUND

Capsular contracture is the main complication in postmastectomy tissue expander and implant breast reconstruction in patients requiring radiotherapy. There is evidence that the wingless signaling pathway plays a central role in the pathogenesis of fibroproliferation in fibromatosis and hyperplastic skin wounds, involving multiple linked events leading to up-regulation of target genes and fibroproliferation. Here, the authors tested their hypothesis that the wingless signaling pathway may also regulate radiotherapy-induced fibroproliferation in capsular tissue around expanders/implants in breast reconstruction.

METHODS

Biopsies of the periprosthetic capsule were obtained from patients undergoing bilateral expander breast reconstruction in which one side was radiated and the other side was not radiated. Capsular biopsies were snap-frozen and stored at -80 degrees C for Western blot assays to determine protein content of phospho-glycogen-synthase-kinase-3beta (phospho-GSK-3beta), total GSK-3beta, beta-catenin, cyclooxygenase-2 (COX-2), and collagen types I and III (n = three to five patients), normalized to beta-actin. Immunostaining for beta-catenin in radiated and nonradiated capsular tissue was also performed. Slides were scanned and analyzed using Zeiss Mirax Scan.

RESULTS

The following protein content levels were significantly (p < 0.01) increased in radiated capsule compared with nonradiated capsule: phospho-GSK-3beta (6.7-fold), total GSK-3beta (3.0-fold), beta-catenin (2.3-fold), COX-2 (2.8-fold), and collagen type I (1.6-fold) and type III (1.8-fold). Immunohistochemical staining demonstrated increased fibroblast cytosolic beta-catenin staining and evidence of beta-catenin nuclear translocation in radiated compared with nonradiated capsular tissue.

CONCLUSION

Results from this study highlight the importance of the wingless signaling pathway in the pathogenesis of radiation-induced fibroproliferation associated with capsular contracture in expander/implant breast reconstruction.

Mammary fibromatosis

OBJECTIVE

This article illustrates the imaging findings that have pathologic correlation and the clinical presentation of mammary fibromatosis.

CONCLUSION

Mammary fibromatosis is a rare, benign, nonmetastasizing stromal tumor. It presents clinically and radiologically as a palpable, spiculated, and locally invasive tumor that is suspicious for malignancy. MRI is ideal for evaluation of chest wall involvement. Although histologically benign, the tumor is locally aggressive and has significant recurrence rates. On occasion, recurrence may require radical surgery.

Desmoid tumor: from surgical extirpation to molecular dissection

PURPOSE OF REVIEW

Desmoid tumors are associated with a variable and unpredictable clinical course. Surgery is the therapeutic mainstay, but there has been much discussion of late regarding its proper application. Little is known regarding the molecular determinates of desmoid tumor behavior. Some recent work has focused on the role of beta-catenin in desmoid tumor biology.

RECENT FINDINGS

Given the variable clinical course of desmoid tumors, the interpretation of factors classically associated with recurrence such as microscopic status of margins appears more nuanced that previously thought. The application of multidisciplinary assessment with multimodality treatment, including surgery, radiation and systemic therapies may underlie these changes and now form the basis of care for this tumor. The precise CTNNB1 mutation present appears to be strongly predictive of recurrence after initial resection in one large, retrospective, multivariate analysis.

SUMMARY

Establishing the population benefiting most from various treatment modalities and combinations is critical for progress in this disease. Assessment and treatment of individual patients in a multidisciplinary setting is critical to achieve the most favorable outcome. Additional study of the molecular determinates of desmoid behavior is needed to guide therapeutic selection.

Beta-catenin expression in pediatric fibroblastic and myofibroblastic lesions: a study of 100 cases

Nuclear immunoreactivity for beta-catenin is a useful adjunct for diagnosis of adult desmoid-type fibromatoses, many of which exhibit mutations within the APC/beta-catenin (Wnt) pathway. Pediatric fibromatoses represent a heterogeneous group of lesions that are diagnostically challenging, especially on biopsy. We studied beta-catenin expression in a variety of pediatric fibroblastic and myofibroblastic lesions. Immunohistochemical nuclear expression of beta-catenin was assessed in 100 tumors. High-level expression of beta-catenin was found in 42% of usual-type or deep fibromatoses (21 of 50). Such expression was not seen in any of the other lesions, including fibrous hamartoma of infancy (0 of 18), juvenile hyaline fibromatosis (0 of 7), infantile digital fibromatosis (0 of 6), myofibromatosis (0 of 5), lipofibromatosis (0 of 4), calcifying aponeurotic fibroma (0 of 3), palmar-plantar fibromatosis (0 of 2), fibromatosis colli (0 of 1), or torticollis (0 of 1). High-level beta-catenin staining is seen in deep "adult-type" fibromatoses occurring in children, although to a lesser frequency than in adult fibromatoses. This indicates that a subset of deep fibromatoses in childhood shares similar mechanisms of tumorigenesis with those in adults. beta-catenin is not expressed in other common pediatric fibroblastic and myofibroblastic lesions, and the Wnt pathway does not appear to play a role in their pathogenesis.

Type-1 Collagen differentially alters beta-catenin accumulation in primary Dupuytren's Disease cord and adjacent palmar fascia cells

Background

Dupuytren's Disease (DD) is a debilitating contractile fibrosis of the palmar fascia characterised by excess collagen deposition, contractile myofibroblast development, increased Transforming Growth Factor-β levels and β-catenin accumulation. The aim of this study was to determine if a collagen-enriched environment, similar to in vivo conditions, altered β-catenin accumulation by primary DD cells in the presence or absence of Transforming Growth Factor-β.

Methods

Primary DD and patient matched, phenotypically normal palmar fascia (PF) cells were cultured in the presence or absence of type-1 collagen and Transforming Growth Factor-β1. β-catenin and α-smooth muscle actin levels were assessed by western immunoblotting and immunofluorescence microscopy.

Results

DD cells display a rapid depletion of cellular β-catenin not evident in patient-matched PF cells. This effect was not evident in either cell type when cultured in the absence of type-1 collagen. Exogenous addition of Transforming Growth Factor-β1 to DD cells in collagen culture negates the loss of β-catenin accumulation. Transforming Growth Factor-β1-induced α-smooth muscle actin, a marker of myofibroblast differentiation, is attenuated by the inclusion of type-1 collagen in cultures of DD and PF cells.

Conclusion

Our findings implicate type-1 collagen as a previously unrecognized regulator of β-catenin accumulation and a modifier of TGF-β1 signaling specifically in primary DD cells. These data have implications for current treatment modalities as well as the design of in vitro models for research into the molecular mechanisms of DD.

Spindle Cell Lesions of the Breast

Spindle cell lesions of the breast represent a heterogeneous group of reactive and neoplastic disorders that commonly present diagnostic challenges. Arguably, the most important of these lesions to recognize is spindle cell carcinoma, a type of metaplastic carcinoma. This review focuses on those spindle cell lesions of the breast that are most likely to be encountered in clinical practice or that produce particular diagnostic difficulties.

Postoperative spindle cell nodule of the breast: Pseudosarcomatous myofibroblastic proliferation following endo-surgery

Despite the frequent use of fine-needle aspiration, core biopsy and surgery, postoperative spindle cell nodule (PSCN) is a rare pathological complication that may be diagnostically treacherous. Presented herein is the case of a 52-year-old woman who developed a 7 mm mammary nodular lesion 66 days after removal of an area of columnar cell hyperplasia involving cellular and architectural atypia, performed with the Mammotome Breast Biopsy System. The lesion was highly cellular and composed of intersecting fascicles of plump spindle cells with blunt-ended elongated nuclei and nucleoli easily visible. Interspersed mononuclear cells and hemosiderin-laden macrophages were evident. PSCN is a reactive, benign myofibroblastic proliferation. Differential diagnosis includes benign and malignant spindle cell lesions of the breast. Recognition of this reactive lesion will avoid overdiagnosis of spindle cell malignant tumor. Attention to clinicopathological and histological features should result in accurate recognition of this lesion.

Desmoid tumour of the breast

Desmoid tumour of the breast is a rare fibroblastic tumour whose spectrum ranges from being locally inert to aggressive and destructive, and represents 0.2% of all breast tumours. A 22-year-old woman, 2 years post-cosmetic augmentation mammoplasty with silicone implants, presented with a 6-month history of an enlarging mass in her left breast. Ultrasound showed a well-defined, hypoechoic mass arising within the muscles of the anterior chest, deep beneath the implant and not involving the underlying rib. Fine needle aspiration (FNA) showed features in keeping with changes associated with silicone implants. A provisional diagnosis of scarring and fibroblastic proliferation was made. The lesion was excised and the implant, noted to be intact, was exchanged. Immunochemistry showed strong positivity for vimentin and variable positivity for SMA and desmin, and patchy positivity for beta catenin. A final diagnosis of aggressive fibromatosis was made. Although the association of desmoid tumour and breast implants has been described, this case is unique as the FNA was highly suggestive of a silicone granuloma and the diagnosis of desmoid tumour was made on definitive pathology. The aetiology of desmoid tumours is reviewed and current treatment modalities discussed.

A subset of cranial fasciitis is associated with dysregulation of the Wnt/beta-catenin pathway

Cranial fasciitis, an unusual fibroproliferative lesion that occurs in the scalp of infants, is considered a posttraumatic reactive process similar to nodular fasciitis. Its pathobiology has not been investigated. Over the last 15 years, we diagnosed cranial fasciitis in six children; in one case, the lesion recurred after 4 years. This lesion and two others showed aberrant, diffuse nuclear reactivity for beta-catenin. One of the lesions with aberrant nuclear beta-catenin occurred in a child with a history of familial adenomatous polyposis (FAP) and a germline frameshift adenomatous polyposis coli (APC) mutation, c.878delG. The other APC allele in this tumor showed an acquired nonsense mutation, c.4132C --> T. Both these mutations lead to translation of a truncated APC protein. The other two cases of cranial fasciitis with aberrant nuclear beta-catenin occurred sporadically. One of these showed a point mutation, c.122C --> T, in exon 3 of CTNNB1. This mutation causes replacement of threonine with isoleucine at codon 41, leading to loss of a phosphorylation site in the beta-catenin protein. The third case with nuclear beta-catenin staining was the single one that showed recurrence. This tumor did not show mutations in exon 3 of CTNNB1 or in exons 8/9/16 of APC. The results of this small study indicate a dysregulation of the Wnt/beta-catenin pathway in a subset of cranial fasciitis, suggesting that this subset is pathobiologically related to desmoid fibromatoses rather than to nodular fasciitis. Occasional cases of cranial fasciitis may be associated with FAP and serve as an early indicator of this disease, information that would be important in the early diagnosis of FAP in patients without a family history of polyposis.

Specific mutations in the beta-catenin gene (CTNNB1) correlate with local recurrence in sporadic desmoid tumors

Desmoid fibromatosis is a rare, nonmetastatic neoplasm marked by local invasiveness and relentless recurrence. Molecular determinants of desmoid recurrence remain obscure. beta-Catenin deregulation has been commonly identified in sporadic desmoids although the incidence of CTNNB1 (the gene encoding beta-catenin) mutations is uncertain. Consequently, we evaluated the prevalence of CTNNB1 mutations in a large cohort of sporadic desmoids and examined whether mutation type was relevant to desmoid outcome. Desmoid specimens (195 tumors from 160 patients, 1985 to 2005) and control dermal scars were assembled into a clinical data-linked tissue microarray. CTNNB1 genotyping was performed on a 138-sporadic desmoid subset. Immunohistochemical scoring was performed per standard criteria and data were analyzed using Kaplan-Meier and other indicated methods. CTNNB1 mutations were observed in 117 of 138 (85%) of desmoids. Three discrete mutations in two codons of CTNNB1 exon 3 were identified: 41A (59%), 45F (33%), and 45P (8%, excluded from further analysis because of rarity). Five-year recurrence-free survival was significantly poorer in 45F-mutated desmoids (23%, P < 0.0001) versus either 41A (57%) or nonmutated tumors (65%). Nuclear beta-catenin expression was observed in 98% of specimens and intensity was inversely correlated with incidence of desmoid recurrence (P < 0.01). In conclusion, CTNNB1 mutations are highly common in desmoid tumors. Furthermore, patients harboring CTNNB1 (45F) mutations are at particular risk for recurrence and therefore may especially benefit from adjuvant therapeutic approaches.

Classification and pathology

Soft tissue tumors are a heterogeneous group of benign and malignant processes. Some are assumed to be reactive; others are clearly neoplastic. Because of their rarity, they frequently pose diagnostic problems for surgical pathologists. Accurate diagnosis of these tumors is enhanced by knowledge of the clinical features of the given lesions and, at times, by application of immunohistochemical and molecular techniques. In this article the lesions are described essentially in accordance with the World Health Organization classification.

Genetic changes of Wnt pathway genes are common events in metaplastic carcinomas of the breast

PURPOSE

Metaplastic carcinomas are distinct invasive breast carcinomas with aberrant nonglandular differentiation, which may be spindle, squamous, or chondroid. The limited effective treatments result from the lack of knowledge of its molecular etiology. Given the role of the Wnt pathway in cell fate and in the development of breast cancer, we hypothesized that defects in this pathway may contribute to the development of metaplastic carcinomas.

DESIGN

In 36 primary metaplastic carcinomas, we comprehensively determined the prevalence of and mechanism underlying beta-catenin and Wnt pathway deregulation using immunohistochemistry for beta-catenin expression and localization and mutational analysis for CTNNB1 (encoding beta-catenin), APC, WISP3, AXIN1, and AXIN2 genes. By immunohistochemistry, normal beta-catenin was seen as membrane staining, and it was aberrant when >5% of tumor cells had nuclear or cytoplasmic accumulation or reduced membrane staining.

RESULTS

By immunohistochemistry, aberrant beta-catenin was present in 33 of 36 (92%) cases, revealing deregulation of the Wnt pathway. CTNNB1 missense mutations were detected in 7 of 27 (25.9%) tumors available for mutation analyses. All mutations affected the NH(2)-terminal domain of beta-catenin, presumably rendering the mutant protein resistant to degradation. Two of 27 (7.4%) tumors had mutations of APC, and 5 (18.5%) carried a frame shift mutation of WISP3. No AXIN1 or AXIN2 mutations were found.

CONCLUSIONS

Activation of the Wnt signaling pathway is common in this specific subtype of breast carcinoma. The discovery of CTNNB1, APC, and WISP3 mutations may result in new treatments for patients with metaplastic carcinomas of the breast.

Beta-catenin mutations do not contribute to cardiac fibroma pathogenesis

Cardiac fibromas are the 2nd most common benign cardiac tumor occurring in children and bear a striking morphologic resemblance to soft tissue or desmoid fibromatosis. Since activating mutations in beta-catenin are common in desmoid fibromatosis as well as other spindle cell proliferations, the aim of our study was to determine if such mutations could be identified in cardiac fibroma. Nine cardiac fibromas from patients with surgical resection were examined for beta-catenin mutations by immunoperoxidase staining for beta-catenin protein and DNA sequencing of a region in exon 3 of the beta-catenin gene, where relatively conserved mutations have been described in desmoid fibromatosis. The mean age of the patients was 7.6 years (range: 10 weeks to 27 years), and 6 of the patients were male. No nuclear staining for beta-catenin was seen in the fibroma cells by immunoperoxidase methods. The beta-catenin exon 3 sequence data showed no mutations in any of the 9 tumors. We conclude that despite their morphologic similarity, cardiac fibroma and desmoid fibromatosis do not share this common molecular pathway of neoplastic growth.

Identification of heterogeneity among soft tissue sarcomas by gene expression profiles from different tumors

The heterogeneity that soft tissue sarcomas (STS) exhibit in their clinical behavior, even within histological subtypes, complicates patient care. Histological appearance is determined by gene expression. Morphologic features are generally good predictors of biologic behavior, however, metastatic propensity, tumor growth, and response to chemotherapy may be determined by gene expression patterns that do not correlate well with morphology. One approach to identify heterogeneity is to search for genetic markers that correlate with differences in tumor behavior. Alternatively, subsets may be identified based on gene expression patterns alone, independent of knowledge of clinical outcome. We have reported gene expression patterns that distinguish two subgroups of clear cell renal carcinoma (ccRCC), and other gene expression patterns that distinguish heterogeneity of serous ovarian carcinoma (OVCA) and aggressive fibromatosis (AF). In this study, gene expression in 53 samples of STS and AF [including 16 malignant fibrous histiocytoma (MFH), 9 leiomyosarcoma, 12 liposarcoma, 4 synovial sarcoma, and 12 samples of AF] was determined at Gene Logic Inc. (Gaithersburg, MD) using Affymetrix GeneChip^® U_133 arrays containing approximately 40,000 genes/ESTs. Gene expression analysis was performed with the Gene Logic Genesis Enterprise System^® Software and Expressionist software. Hierarchical clustering of the STS using our three previously reported gene sets, each generated subgroups within the STS that for some subtypes correlated with histology, and also suggested the existence of subsets of MFH. All three gene sets also recognized the same two subsets of the fibromatosis samples that we had found in our earlier study of AF. These results suggest that these subgroups may have biological significance, and that these gene sets may be useful for sub-classification of STS. In addition, several genes that are targets of some anti-tumor drugs were found to be differentially expressed in particular subsets of STS.

Recent developments in the histological diagnosis of spindle cell carcinoma, fibromatosis and phyllodes tumour of the breast

This article reviews recent advances in the diagnosis of these three unusual tumours of the breast. Spindle cell carcinoma needs to be considered in the differential diagnosis of many mammary spindle cell lesions: it is important to be aware of the wide range of appearances, including the recently described fibromatosis-like variant. Immunohistochemistry using a broad panel of cytokeratin antibodies is needed to exclude spindle cell carcinoma; there is frequent expression of basal cytokeratins and p63. CD34 is often expressed by the stroma of phyllodes tumours, but does not appear to be expressed by spindle cell carcinoma or fibromatosis. Nuclear beta-catenin is found in about 80% of fibromatoses, but can also be seen in spindle cell carcinomas and phyllodes tumours. Two recent studies have described features useful in the distinction of phyllodes tumour and fibroadenoma on core biopsy, including increased cellularity, mitoses and overgrowth of the stroma, adipose tissue in the stroma and fragmentation of the biopsy specimen. Periductal stromal tumour is a recently described biphasic tumour composed of spindle cells around open tubules or ducts (but no leaf-like architecture) with frequent CD34 expression. The overlap of morphology with phyllodes tumour suggests that it may be best regarded as a variant of phyllodes tumour.

Detection of beta-catenin mutations in paraffin-embedded sporadic desmoid-type fibromatosis by mutation-specific restriction enzyme digestion (MSRED): an ancillary diagnostic tool

Desmoid-type fibromatosis is a locally aggressive deep soft tissue tumor. Some cases are associated with adenosis polyposis coli germline mutations whereas others harbor somatic beta-catenin point mutations mainly in exon 3, codons 41 and 45. These mutations result in stabilization of beta-catenin, and activation of the Wnt signaling pathway. The aim of this study was to determine the specificity and sensitivity of these 3 most common beta-catenin mutations in the diagnosis of desmoid-type fibromatosis using paraffin-embedded material. The results were compared with nuclear expression of beta-catenin. Mutation-specific restriction enzyme digestion methodology was employed to detect the 3 mutations. One hundred and thirty-three cases were analyzed, including 76 desmoid-type, and 18 superficial fibromatosis, in addition to a further 39 fibromatosis mimics. A restriction site was present for analysis of the codon 41 mutation. Mismatch primers were designed for the codon 45 mutations. Mutations were detected in 66 cases (87%) of 76 desmoid-type fibromatosis (71 extra-abdominal). Of these, 34 (45%) were in codon 45 (TCT>TTT), 27 (35%) in codon 41 (ACC>GCC), and 5 (7%) in codon 45 (TCT>CCT). No mutations were detected in the other lesions studied. All desmoid-type fibromatosis cases and 72% of the mimics tested showed nuclear positivity for beta-catenin indicating immunohistochemistry is a sensitive but not a specific test for desmoid-type fibromatosis. In contrast, to date, beta-catenin mutations have not been detected in any lesions which mimic desmoid-type fibromatosis. Mutation-specific restriction enzyme digestion, a simple and efficient means of detecting the common beta-catenin mutations in desmoid-type fibromatosis, complements light microscopy in reaching a diagnosis.

Desmoid Tumors (Fibromatoses) of the Breast: A 25-Year Experience

BACKGROUND

Breast desmoid tumors are rare and often clinically mistaken for carcinoma. We reviewed our 25-year institutional experience with breast desmoid tumors.

METHODS

A search of pathology and sarcoma databases (1982-2006) identified 32 patients with pathologically confirmed breast desmoids. Records were retrospectively reviewed.

RESULTS

Median presentation age was 45 years (range, 22-76). Eight patients (25%) had prior history of breast cancer and 14 (44%) of breast surgery, with desmoids diagnosed a median of 24 months postoperatively. All presented with physical findings. Mammography visualized the mass in 6/16, ultrasound in 9/9, and magnetic resonance imaging (MRI) in 8/8 patients in whom it was performed. In 15 patients with attempted needle biopsy, fine needle aspiration was inconclusive (9/9 patients), and core biopsy demonstrated a spindle cell lesion (6/7 patients). Treatment was surgical, with median tumor size of 2.5 cm (range, 0.3-15). Eight patients (29%) had recurring tumors at a median 15 months. Patients with recurring tumors were younger (median age: 28 vs. 46 years, p = 0.03). A trend toward more frequent recurrences in patients with positive (5/9 patients) versus negative (3/19 patients) margins (p = 0.07) and larger tumors (p = 0.12) was observed.

CONCLUSIONS

In our series, breast desmoids presented as palpable masses suspicious for carcinoma clinically and radiographically. Therapy remains primarily surgical, and core biopsy aided in operative planning. Recurrences are common, with younger age and possibly positive margin status and larger tumor size associated with increased risk of recurrence. As 5/9 patients with positive and 3/19 patients with negative margins experienced recurrences, clinical judgment should be used prior to extensive and potentially deforming resections.

Immunohistochemistry for beta-catenin in the differential diagnosis of spindle cell lesions: analysis of a series and review of the literature

AIMS

Nuclear staining for beta-catenin by immunohistochemistry is being used increasingly to diagnose desmoid tumours (deep fibromatoses), especially where the differential diagnosis includes other abdominal spindle cell neoplasms. This study aimed to define the prevalence of beta-catenin positivity in desmoid tumours and other morphologically similar spindle cell neoplasms.

METHOD AND RESULTS

Nuclear beta-catenin expression was evaluated by immunohistochemistry in 270 soft tissue tumours. Nuclear immunopositivity was detected in 80% of cases of sporadic desmoid fibromatosis (24/30) and in 67% of tumours in patients with familial adenomatous polyposis (8/12). Nuclear positivity was also present in 14/25 superficial fibromatoses (56%), 3/10 low-grade myofibroblastic sarcomas (30%), 5/23 solitary fibrous tumours (22%), 1/5 infantile fibrosarcomas (20%), 1/18 desmoplastic fibroblastomas (6%) and 1/21 gastrointestinal stromal tumours (5%). No nuclear immunoreactivity was present in neurofibromas (0/26), schwannomas (0/25), nodular fasciitis (0/19), leiomyosarcomas (0/16), inflammatory myofibroblastic tumours (0/12), fibromas of tendon sheath (0/9), lipofibromatoses (0/5), Gardner fibromas (0/4), calcifying aponeurotic fibromas (0/4) or fibromatosis colli (0/1).

CONCLUSION

Nuclear staining for beta-catenin is supportive, but not definitive, of the diagnosis of desmoid fibromatosis. No significant difference in immunoreactivity was observed between sporadic and familial desmoid fibromatoses. beta-Catenin negativity does not preclude the diagnosis of fibromatosis.

Gardner Fibroma: A Clinicopathologic and Immunohistochemical Analysis of 45 Patients With 57 Fibromas

Gardner fibroma (GAF) is a benign soft tissue lesion with a predilection for childhood and adolescence and an association with familial adenomatous polyposis (FAP) and desmoid type fibromatosis (desmoid). We report 45 patients with GAF with clinicopathologic correlation and immunohistochemical analysis for beta-catenin and related proteins. Forty-five patients with 57 GAFs were identified from surgical pathology and consultation files. Immunohistochemistry for beta-catenin, cyclin-D1, and C-myc was performed on formalin-fixed, paraffin-embedded tissues using standard techniques in 25 GAFs from 24 patients. Information about family history, intestinal polyps, colon cancer, and soft tissue tumors was available in 23 patients. Sixty-nine percent had known FAP or adenomatous polyposis coli (APC), 22% had no history of familial polyps or soft tissue tumors, and 13% had an individual or family history of soft tissue masses and/or desmoids, with follow-up periods of 6 months to 26 years (median 3 y, mean 5 y). The age range at initial diagnosis was 2 months to 36 years. Seventy-eight percent were diagnosed in the first decade, 15% in the second decade, and 7% in the third decade. Eight patients (18%) had documented desmoids concurrently or later; 4 of these had FAP and 1 had familial desmoids. Sites of GAF included the back and paraspinal region in 61%, the head and neck in 14%, the extremities in 14%, and the chest and abdomen in 11%. All displayed a bland hypocellular proliferation of haphazardly arranged coarse collagen fibers with a bland hypocellular proliferation of inconspicuous spindle cells, small blood vessels, and a sparse mast cell infiltrate. Immunohistochemically, 64% showed nuclear reactivity for beta-catenin (9 patients with known APC, 5 without definite information about FAP). One hundred percent showed nuclear reactivity for both cyclin-D1 and C-myc. beta-catenin reactivity had no correlation with age, site, or recurrence. Two beta-catenin-negative GAFs were from FAP patients. In conclusion, GAF has a predilection for childhood and early adulthood, a strong association with FAP/APC, an association with concurrent or subsequent development of desmoids, and overexpression of beta-catenin and other proteins in the APC and Wnt pathways. The proportion of sporadic GAFs that have APC mutation remains to be determined.

Wnt Signaling Pathway in Mammary Gland Development and Carcinogenesis

The signaling pathway mediated by Wingless-type (Wnt) proteins is highly conserved in evolution. This pivotal pathway is known to regulate cell fate decisions, cell proliferation, morphology, migration, apoptosis, differentiation and stem cell self-renewal. It currently includes the canonical or Wnt/beta-catenin pathway in which Wnt proteins bind to 'frizzled' receptors, which leads to downstream activation of gene transcription by beta-catenin. Second, the noncanonical or beta-catenin-independent pathways are now known to be mediated by three possible mechanisms: (1) the Wnt/Ca(2+) pathway, (2) the Wnt/G protein signaling pathway, and (3) the Wnt/PCP or planar cell polarity pathway. Wnt signaling is implicated at several stages of mammary gland growth and differentiation, and possibly in the involution of mammary gland following lactation. Recent evidence suggests the role of Wnt signaling in human breast cancer involves elevated levels of nuclear and/or cytoplasmic beta-catenin using immunohistochemistry, overexpression or downregulation of specific Wnt proteins, overexpression of CKII and sFRP4, downregulation of WIF-1 and sFRP1, as well as amplification of DVL-1. Further research is required to determine how Wnt signaling is involved in the development of different histological types of breast cancer and whether it promotes the viability of cancer stem cells or not.

Pleuropulmonary desmoid tumors: immunohistochemical comparison with solitary fibrous tumors and assessment of beta-catenin and cyclin D1 expression

CONTEXT

Desmoid tumors arising in the lung and pleura are extremely rare and can resemble other, more common neoplasms native to these sites. Alterations of the adenomatous polyposis coli/beta-catenin pathway have been detected in sporadic desmoid tumors and have been associated with nuclear accumulation of beta-catenin and overexpression of cyclin D1.

OBJECTIVE

To analyze the expression of beta-catenin and cyclin D1 in desmoid tumors and solitary fibrous tumors (SFTs), and to compare the utilities of these substances for distinguishing between these entities with those of other, more commonly used stains.

DESIGN

Formalin-fixed, paraffin-embedded sections of 4 desmoid tumors (1 pulmonary, 1 pleural, 2 pleural/chest wall), and 5 benign and 6 malignant SFTs of the pleura were immunostained for beta-catenin, cyclin D1, ALK1, CD34, vimentin, desmin, smooth muscle actin, muscle-specific actin, S100, and pancytokeratin. Staining intensity and the percentage of stained tumor cells were assessed semiquantitatively.

RESULTS

Diffuse moderate or strong nuclear staining for beta-catenin was found in all desmoid tumors, 4 of 5 benign SFTs, and 2 of 6 malignant SFTs. All cases except 1 benign SFT showed concurrent cytoplasmic staining. Nuclear and cytoplasmic cyclin D1 staining was increased in all groups. The best distinction between desmoid tumors and SFTs was provided by CD34 (desmoid tumors, 0/4; SFTs, 8/11) and smooth muscle actin (desmoid tumors, 4/4; SFTs, 0/11).

CONCLUSIONS

Our findings suggest that alterations in the adenomatous polyposis coli/beta-catenin pathway and cyclin D1 dysregulation may contribute to the pathogenesis of pleuropulmonary desmoid tumors and SFTs. CD34 and smooth muscle actin stains are particularly useful for differentiating between pleuropulmonary desmoid tumors and SFTs.

Unusual benign breast lesions

The purpose of this article is to show examples of the radiological (mammography and/or ultrasound) and pathological appearances of unusual benign breast lesions. The conditions covered are granular cell tumours, fibromatosis, nodular fasciitis, myofibroblastomas, haemangiomas, neurofibromas, and leiomyomas. The article includes the first published description of the ultrasound appearance of a myofibroblastoma. Knowledge of these appearances may help confirm or refute radiological-pathological concordance of percutaneous biopsy results during multidisciplinary assessment of these lesions and aid patient management.

Fibromatosis of the breast: case report and current concepts in the management of an uncommon lesion

Fibromatosis is an uncommon breast lesion that can mimic breast carcinoma in its clinical presentation. We present a case in which excisional biopsy was necessary to establish a diagnosis of fibromatosis. Clinical, diagnostic imaging, and pathologic features are discussed. Magnetic resonance imaging (MRI) has emerged as a tool for further characterization of breast lesions and as a screening modality in high-risk patient populations. Ours marks the second case in which dynamic MRI has been correlated with histologically confirmed primary mammary fibromatosis. Unlike the previous report, MRI in this case mimics breast carcinoma in its morphologic and pharmacokinetic features of enhancement. Wide local excision with clear margins remains the treatment of choice. Current data on radiotherapy and pharmacologic therapy for mammary fibromatosis are reviewed.

Cytomorphology of Benign Breast Disease

Fine needle aspiration biopsy is a widely used technique for the initial diagnosis of mammary lesions. The majority of patients undergoing fine needle aspiration biopsy of a breast lesion will have a benign disease of the breast. This article provides a review of the cytomorphologic features in a variety of benign breast lesions,and discusses the commonly encountered differential diagnoses on aspiration biopsy. Topics discussed include inflammatory and reactive conditions, treatment-induced changes, pregnancy-related changes, benign proliferative lesions, and benign neoplasms of the breast.

Immunohistochemical expression of beta-catenin in solitary fibrous tumors

CONTEXT

Immunohistochemical staining for beta-catenin may be used as an indicator of the integrity of the Wnt signaling and beta-catenin degradation pathways. Among mesenchymal tumors, aberrant nuclear localization of beta-catenin is seen in desmoid-type fibromatoses but has not been described for solitary fibrous tumors that may mimic the former lesions, especially in small biopsy samples.

OBJECTIVE

To study the immunohistochemical expression of beta-catenin in solitary fibrous tumors.

DESIGN

We performed immunohistochemical staining for beta-catenin in 12 solitary fibrous tumors, one of which showed histologic features of malignancy.

RESULTS

All the tumors showed strong and diffuse reactivity for beta-catenin. Four tumors (33%) showed nuclear staining for beta-catenin, whereas the remaining tumors showed either a membranous or mixed membranous and cytoplasmic pattern of staining. The only histologically malignant tumor of the group showed a mixed membranous and cytoplasmic pattern of staining for beta-catenin.

CONCLUSIONS

Immunohistochemical staining for beta-catenin in solitary fibrous tumors does not show a consistent pattern, which may be due to differences in tumorigenesis. Larger studies with clinical follow-up are required for estimating the impact of the variable staining pattern on clinical behavior of these tumors.

The diagnostic value of beta-catenin immunohistochemistry

beta-catenin is a 92-kDa protein that binds to the cytoplasmic tail of E-cadherin. It acts in the nucleus to stimulate cell proliferation and is degraded by complexing with the adenomatous polyposis coli gene. When it is mutated, it is ineffectively degraded and results in unchecked proliferative activity that plays a role in a subset of neoplasms. When there are alterations in beta-catenin degradation, it accumulates to a sufficient extent to be detected in the nuclei of tumor cells immunohistochemically, a feature that can be exploited in the differential diagnosis of selected neoplasms. Immunohistochemistry for beta-catenin may be useful in the differential diagnosis of selected tumors of soft tissue, the gastrointestinal tract, including the pancreas, lung, and female genital tract.

Desmoid tumor with ossification in chest wall: possible involvement of BAMBI promoter hypermethylation in metaplastic bone formation

A rare case of desmoid-type fibromatosis with focal metaplastic bone in the chest wall suggested that enhanced responsiveness to BMP signaling by decreasing BAMBI expression through promoter hypermethylation plays a crucial role in the formation of metaplastic bone.

INTRODUCTION

Desmoid-type fibromatosis, originating from mesenchymal cells with myofibroblastic features, is a locally aggressive and frequently recurring infiltrative lesion. One such sporadic case with metaplastic ossification in the chest wall is presented.

MATERIALS AND METHODS

A 43-year-old man was referred to the hospital with a gradually enlarging hard mass in the left anterolateral chest wall. A thoracotomy was carried out, and histopathological specimens were used for immunohistochemical, genetic, and methylation studies.

RESULTS

Accumulation of altered beta-catenin associated with a somatic heterozygous activating mutation in codon 41 was detected in the typical desmoid-type fibromatosis and at the ossifying focus. Among factors related to bone formation and the classical wnt-beta-catenin signaling pathway, BMP and activin membrane-bound inhibitor (BAMBI) expression was specifically downregulated at the ossifying focus. Hypermethylation of the BAMBI promoter was observed in microdissected tissue from the ossifying focus but not in that from the typical desmoid-type fibromatosis.

CONCLUSIONS

Because both BMP and classical Wnt/beta-catenin/LEF1 signaling cooperatively and mutually induce differentiation of mesenchymal cells into osteoblastic cells and promote bone formation, the epigenetic event leading to the enhanced responsiveness to BMP signaling may play a crucial role in the formation of metaplastic bone.

Nuclear beta-catenin expression distinguishes deep fibromatosis from other benign and malignant fibroblastic and myofibroblastic lesions

Deep fibromatoses (desmoid tumors) are clonal myofibroblastic proliferations that are prone to aggressive local recurrences but that do not metastasize. They must be distinguished from a host of fibroblastic and myofibroblastic lesions as well as from smooth muscle neoplasms. Virtually all deep fibromatoses have somatic beta-catenin or adenomatous polyposis coli (APC) gene mutations leading to intranuclear accumulation of beta-catenin. Since low-grade sarcomas in general lack beta-catenin and since reactive proliferations would not be expected to have it, we predicted that nuclear beta-catenin expression would be detected in deep fibromatoses but absent in other entities in the differential diagnosis. We evaluated the role of beta-catenin to help differentiate distinguish deep fibromatoses from congeners. Formalin-fixed, paraffin-embedded sections from 21 lesions from 20 patients with deep fibromatoses were stained with monoclonal beta-catenin antibody (Transduction Laboratories) and compared with low-grade fibromyxoid sarcoma (n=12), leiomyosarcoma (n=10), various other fibrosarcoma variants (n=13, including 3 myofibrosarcomas, 3 sclerosing epithelioid fibrosarcomas, 5 low-grade fibrosarcomas, 1 classic fibrosarcoma arising in dermatofibrosarcoma protuberans, 1 inflammatory myxohyaline tumor/myxoinflammatory fibroblastic sarcoma), myofibroma/myofibromatosis (n=12), nodular fasciitis (n=11), and scars (n=9). Nuclear and cytoplasmic staining was assessed. All 21 examples of deep fibromatosis displayed nuclear beta-catenin (focal nuclear staining in one case to 90% staining). All other lesions tested (n=67) lacked nuclear labeling for beta-catenin, showing only cytoplasmic accumulation. beta-Catenin immunohistochemistry separates deep fibromatosis from entities in the differential diagnosis, a finding that can be exploited for diagnosis. Most fibromatoses have diffuse nuclear staining although occasional examples only focally label.

Cystic Renal Neoplasia Following Conditional Inactivation of Apc in Mouse Renal Tubular Epithelium

Alterations in Wnt/beta-catenin signaling have been linked to abnormal kidney development and tumorigenesis. To gain more insights into the effects of these alterations, we created mice carrying a conditional deletion of the Apc tumor suppressor gene specifically in the renal epithelium. As expected, the loss of Apc leads to increased levels of beta-catenin protein in renal epithelium. Most of these mice die shortly after birth, and multiple kidney cysts were found upon histological examination. Only rarely did these animals survive to adulthood. Analysis of these adults revealed severely cystic kidneys associated with the presence of renal adenomas. Our results confirm an important role for proper regulation of Wnt/beta-catenin signaling in renal development and provide evidence that dysregulation of the pathway can initiate tumorigenesis in the kidney.

Nuclear beta-catenin in mesenchymal tumors

Beta-catenin is a crucial part of the Wnt and E-cadherin signalling pathways, which are involved in tumorigenesis. Dysregulation of these pathways allow beta-catenin to accumulate and translocate to the nucleus, where it may activate oncogenes. Such nuclear accumulation can be detected by immunohistochemistry, which may be useful in diagnosis. Although the role of beta-catenin has been established in various types of carcinomas, relatively little is known about its status in mesenchymal tumors. A number of studies suggest that beta-catenin dysregulation is important in desmoid-type fibromatosis, as well as in synovial sarcoma. We wished to determine whether nuclear beta-catenin expression is specific to and sensitive for particular bone and soft-tissue tumors, including sporadic desmoid-type fibromatosis. We studied the nuclear expression of beta-catenin using tissue microarrays in a comprehensive range of bone and soft-tissue tumor types. A total of 549 cases were included in our panel. Nuclear immunohistochemical staining was determined to be either high level (>25% of cells), low level (0-25%) or none. High-level nuclear beta-catenin staining was seen in a very limited subset of tumor types, including desmoid-type fibromatosis (71% of cases), solitary fibrous tumor (40%), endometrial stromal sarcoma (40%) and synovial sarcoma (28%). Although occasional cases of fibrosarcoma, clear cell sarcoma and carcinosarcoma had high-level staining, no high-level nuclear beta-catenin expression was seen in any of 381 fibrohistocytic, muscular, adipocytic, chondroid or osseous tumor cases representing 42 diagnostic categories. All primary immunostain tissue microarray images are made publicly accessible in a searchable database. High-level nuclear beta-catenin staining serves as a useful diagnostic tool, as it is specific to a small subset of mesenchymal tumors.

Benign and malignant spindle cell lesions of the breast

Spindle cell lesions of the breast constitute a wide spectrum of benign and malignant proliferations. Myofibroblasts, normal cellular constituents of the mammary intra- and interlobular stroma, compose many of these lesions, which include reactive proliferations and benign or locally aggressive neoplasms. Because of its morphology, low-grade metaplastic spindle cell carcinoma, "fibromatosis-like" is also considered together with spindle cell lesions of the breast. Although certain of the lesions do not occur commonly, they represent diagnostic challenges. This review outlines the morphology of certain spindle cell lesions of the breast including pseudoangiomatous stromal hyperplasia, reactive spindle cell nodule, nodular fasciitis, myofibroblastoma, primary mammary fibromatosis, and low-grade metaplastic spindle cell carcinoma, "fibromatosis-like." The differential diagnosis and diagnostic work-up of these lesions is discussed, and their clinical treatment and prognosis briefly summarized.

Gene expression in aggressive fibromatosis

Aggressive fibromatosis represents a group of tumors with heterogeneous patterns of biologic behavior. In this study, gene expression in 12 samples of aggressive fibromatosis, as well as that in samples of normal skeletal muscle and a variety of normal tissues, was determined at Gene Logic Inc (Gaithersburg, MD), with the use of Affymetrix GeneChip U_133 arrays containing approximately 33,000 genes. Gene-expression analysis was performed with the Gene Logic Gene Express software system. Differences in gene expression were quantified as the fold change in gene expression between the sets of fibromatosis tissue and normal skeletal muscle. A set of genes was then identified that was significantly overexpressed in aggressive fibromatosis compared with expression in normal muscle. This set of genes was then further examined for expression in a variety of normal tissues. We identified genes that were selectively overexpressed in aggressive fibromatosis compared with expression in 448 samples comprising 16 different nonneoplastic tissues. In particular, ADAM12, WISP-1, SOX-11, and fibroblast activation protein-alpha were uniquely overexpressed in aggressive fibromatosis compared with expression in normal tissues. In addition, the technique of Eisen clustering identified 2 distinct subgroups of aggressive fibromatosis with regard to gene expression. We conclude that gene-expression patterns may be useful in the further classification of subtypes of aggressive fibromatosis and that such classification could have clinical significance.

Elevated levels of beta-catenin and fibronectin in three-dimensional collagen cultures of Dupuytren's disease cells are regulated by tension in vitro

BACKGROUND

Dupuytren's contracture or disease (DD) is a fibro-proliferative disease of the hand that results in the development of scar-like, collagen-rich disease cords within specific palmar fascia bands. Although the molecular pathology of DD is unknown, recent evidence suggests that beta-catenin may play a role. In this study, collagen matrix cultures of primary disease fibroblasts show enhanced contraction and isometric tension-dependent changes in beta-catenin and fibronectin levels.

METHODS

Western blots of beta-catenin and fibronectin levels were determined for control and disease primary cell cultures grown within stressed- and attached-collagen matrices. Collagen contraction was quantified, and immunocytochemistry analysis of filamentous actin performed.

RESULTS

Disease cells exhibited enhanced collagen contraction activity compared to control cells. Alterations in isometric tension of collagen matrices triggered dramatic changes in beta-catenin and fibronectin levels, including a transient increase in beta-catenin levels within disease cells, while fibronectin levels steadily decreased to levels below those seen in normal cell cultures. In contrast, both fibronectin and beta-catenin levels increased in attached collagen-matrix cultures of disease cells, while control cultures showed only increases in fibronectin levels. Immunocytochemistry analysis also revealed extensive filamentous actin networks in disease cells, and enhanced attachment and spreading of disease cell in collagen matrices.

CONCLUSION

Three-dimensional collagen matrix cultures of primary disease cell lines are more contractile and express a more extensive filamentous actin network than patient-matched control cultures. The elevated levels of beta-catenin and Fn seen in collagen matrix cultures of disease fibroblasts can be regulated by changes in isometric tension.

Beta-catenin expression in Dupuytren's disease: potential role for cell-matrix interactions in modulating beta-catenin levels in vivo and in vitro

Dupuytren's disease (DD) is a superficial fibromatosis of the hand. Although the molecular mechanisms responsible for this disease are unknown, recent studies suggest that beta-catenin may be a key factor involved in fibromatosis. In this study, we analysed the in vivo and in vitro expression levels of beta-catenin in DD, using surgical specimens and primary cell lines. Although no somatic mutations (exon 3) of beta-catenin were detected, Western blot analysis revealed high levels of beta-catenin in diseased palmar fascia, and low to undetectable levels of beta-catenin in patient-matched normal palmar fascia. Immunohistochemistry analysis showed high levels of beta-catenin expression within the disease fascia, as well as cytoplasmic and nuclear accumulations of the protein. Immunoprecipitation of beta-catenin from seven patient lesions showed the protein to be tyrosine phosphorylated. Lastly, Western analysis of three patient-matched (disease and normal fascia) primary cell cultures showed significantly elevated levels of beta-catenin in disease cells cultured in three-dimensional collagen lattices. This is the first extensive in vivo and in vitro characterization of beta-catenin in DD, and the first to suggest that the extracellular matrix may play an important role in modulating beta-catenin stability in DD.

Caught up in a Wnt storm: Wnt signaling in cancer

The Wnt signaling pathway, named for its most upstream ligands, the Wnts, is involved in various differentiation events during embryonic development and leads to tumor formation when aberrantly activated. Molecular studies have pinpointed activating mutations of the Wnt signaling pathway as the cause of approximately 90% of colorectal cancer (CRC), and somewhat less frequently in cancers at other sites, such as hepatocellular carcinoma (HCC). Ironically, Wnts themselves are only rarely involved in the activation of the pathway during carcinogenesis. Mutations mimicking Wnt stimulation-generally inactivating APC mutations or activating beta-catenin mutations-result in nuclear accumulation of beta-catenin which subsequently complexes with T-cell factor/lymphoid enhancing factor (TCF/LEF) transcription factors to activate gene transcription. Recent data identifying target genes has revealed a genetic program regulated by beta-catenin/TCF controlling the transcription of a suite of genes promoting cellular proliferation and repressing differentiation during embryogenesis, carcinogenesis, and in the post-embryonic regulation of cell positioning in the intestinal crypts. This review considers the spectra of tumors arising from active Wnt signaling and attempts to place perspective on recent data that begin to elucidate the mechanisms prompting uncontrolled cell growth following induction of Wnt signaling.

Solid-pseudopapillary tumors of the pancreas are genetically distinct from pancreatic ductal adenocarcinomas and almost always harbor beta-catenin mutations

Solid-pseudopapillary tumors (SPTs) are unusual pancreatic neoplasms of low malignant potential that most frequently affect young women. Genetic events contributing to the development of SPTs are unknown. Whereas the more common ductal adenocarcinomas of the pancreas essentially never harbor beta-catenin or APC gene mutations, we have recently identified alterations of the APC/beta-catenin pathway in other nonductal pancreatic neoplasms including pancreatoblastomas and acinar cell carcinomas. We analyzed a series of 20 SPTs for somatic alterations of the APC/beta-catenin pathway using immunohistochemistry for beta-catenin protein accumulation, direct DNA sequencing of beta-catenin exon 3, and direct DNA sequencing of the mutation cluster region in exon 15 of the APC gene in those SPTs that did not harbor beta-catenin mutations. Immunohistochemical labeling for cyclin D1 was performed to evaluate the overexpression of this cell-cycle protein as one of the putative downstream effectors of beta-catenin dysregulation. In addition, we analyzed the SPTs for genetic alterations commonly found in pancreatic ductal adenocarcinomas, including mutations in the K-ras oncogene and p53 and DPC4 tumor suppressor genes, using direct DNA sequencing of K-ras and immunostaining for p53 and Dpc4. Almost all SPTs harbored alterations in the APC/beta-catenin pathway. Nuclear accumulation of beta-catenin protein was present in 95% (19 of 20), and activating beta-catenin oncogene mutations were identified in 90% (18 of 20) of the SPTs. Seventy-four percent (14 of 19) showed overexpression of cyclin D1, ranging from 10 to 70% of tumor nuclei. In contrast, no K-ras mutations were present in any of the 20 SPTs, and Dpc4 expression was intact in all 16 SPTs for which immunohistochemical labeling was successful. Overexpression of p53 was limited to only 3 of 19 (15.8%) SPTs. These results emphasize the two distinct, divergent genetic pathways of neoplastic progression in pancreatic ductal and nonductal neoplasms.