Cytogenetic analysis shows that carcinosarcomas of the breast are of monoclonal origin

Odontogenic Carcinosarcoma: Clinicopathologic and Molecular Features of Three Cases, a Literature Review and Nomenclature Proposal

BACKGROUND

Odontogenic carcinosarcoma (OCS) is a rare odontogenic malignancy with limited characterization and unexplored molecular features. We report clinicopathologic and molecular findings in 3 additional OCS and review the literature.

METHODS

3 OCS (5.1%) were identified among 59 malignant odontogenic tumors (in our archives from 1992 to 2022). Clinical, radiologic, histopathologic, immunophenotypic, and molecular findings were reviewed. Data from prior case reports and systematic or non-systematic reviews were extracted for analysis.

RESULTS

Three mandibular OCS (age range: 66 to 72 years; 1 male, 2 females) were identified. Case 1 had novel clear-cell morphology, multiple recurrences, and a lethal outcome 28 months after resection. EWSR1 rearrangements were negative, but the tumor showed focal nuclear β-catenin and strong LEF-1 immunoreactivity. Case 2 demonstrated ameloblastic and sclerosing features and encased the inferior alveolar nerve; the patient was disease-free 22 months after resection with adjuvant chemoradiation therapy. LEF-1 was again strongly positive, and next-generation sequencing demonstrated 9p region-(CDKN2A, CDKN2B) copy number loss, and 12q region-(MDM2, CDK4) copy number gain. Case 3 showed clear-cell and markedly sclerosing features; no follow-up information was available. Literature review along with the current cases yielded 20 cases. OCS showed a male predilection (1.5:1), mandibular predominance (80%, typically posterior), and a bimodal age distribution (modes: 27.7 years, 62.7 years). OCS presented as masses (100%), often with pain (55%), and paresthesia (45%). Tumors were typically radiolucent (88.9%), with bone destruction (61.1%), and/or tooth effacement (27.8%). Preoperative biopsy was sensitive for malignancy (85.7%). At least 45% show evidence for a precursor lesion. 3-year DSS and DFS were 58% and 35%, respectively. Regional and distant (usually lung) metastatic rates were 25% and 31.3%, respectively. Increased mitotic rates and presence of tumor necrosis trended toward worse DSS and DFS.

CONCLUSION

OCS is a rare but aggressive malignancy, often arising from precursor tumors and may represent a terminal phenotype rather than a distinct entity. We describe novel clear-cell and sclerosing morphologies. Wnt pathway alterations appear important. Mitotic rates and necrosis may be adverse prognosticators. In keeping with nomenclature trends in other sites, OCS may be more appropriately designated as "biphasic sarcomatoid odontogenic carcinomas."

Analysis of Clinicopathological Characteristics and Prognosis of Carcinosarcoma of the Breast

Background. Few cases of carcinosarcoma of the breast have been reported because of its low incidence rate and rapid progression. Seeking effective therapeutic methods becomes urgent in clinical practice. This study was aimed to investigate the clinical characteristics of carcinosarcoma of the breast and to explore proper therapeutic methods for patients with this rare tumor. Methods. We conducted a retrospective analysis on 47 patients with carcinosarcoma of the breast receiving treatment in our hospital from 2003 to 2020. Most of these patients received primary surgery followed by adjuvant chemotherapy, while four patients had lumpectomy only. Statistics showed no preference in age and menopausal status of patients. Results. The overall survival rate and progression-free survival rate of all patients at a median follow-up time of 33 months were 63.8% and 57.4%, respectively. Tumor size at diagnosis and chemotherapy strategies were both significant prognostic factors in reference to disease-free survival (DFS) and overall survival (OS) of the patients (tumor size: $p=0.023$ for DFS and $p=0.021$ for OS; therapeutic method: $p=0.041$ for DFS and $p=0.024$ for OS). N stage at diagnosis was significant only with reference to overall survival of the patients ( $p=0.009$ ). EGFR expression was positive in some patients. Conclusions. Our results elucidated that the patients received comprehensive therapy, especially adjuvant chemotherapy was indispensable for better outcomes. Early detection and treatment were necessary for a higher survival rate when the tumor size was less than 5 cm without lymph node metastasis. Prospective outcomes with novel strategies targeting EGFR need to be further investigated.

Clinicopathological Examination of Metaplastic Spindle Cell Carcinoma of the Breast: Case Series

Background:

Spindle cell carcinoma (SpCC) of the breast is a rare histological type, a subtype of metaplastic carcinoma characterized by atypical spindle cell and epithelial carcinoma. The proportions of the spindle cell and epithelial components vary among tumours. Due to its rarity, biological characteristics of this disease have been poorly studied.

Methods:

In total, 10 patients with SpCC were surgically treated at our institution from January 2007 to December 2018. We retrospectively investigated these SpCC cases, focusing on the differences between spindle cell and epithelial components. Microsatellite status was also examined.

Results:

Nine cases were triple-negative breast cancer (TNBC). The rates of high tumour grade were 70% in spindle cell components and 56% in epithelial components (P = .65), while the mean Ki67 labelling index were 63% and 58%, respectively (P = .71). Mean programmed death ligand 1 (PD-L1) expression in these components was 11% and 1%, respectively (P = .20). All 10 tumours were microsatellite stable. Patient outcomes of triple-negative SpCC did not differ from those of propensity-matched patients with conventional TNBC.

Conclusions:

Spindle cell components showed higher values in factors examined, although there was no statistically significant difference. Our data reveal that these 2 components of SpCC may be of different biological nature.

A Case of Carcinosarcoma of the Breast Presenting as Inflammatory Carcinoma and Review of the Literature

Carcinosarcoma, also known as metaplastic carcinoma, is a rare and aggressive malignant tumor. We report a case of metaplastic carcinoma presenting as inflammatory carcinoma and provide a review of the related literature. A 38-year-old breastfeeding woman presented with concerns about a painful lump in her left breast. The symptoms had been present for two months. After admission to the hospital, the triple assessment revealed findings consistent with inflammatory carcinoma of the breast. The patient underwent modified radical mastectomy. Histopathological examination revealed a gray-white tumor with a biphasic pattern with features of ductal carcinoma as well as squamous and sarcomatous differentiation. On immunohistochemistry, the neoplastic cells were positive for cytokeratin and vimentin, and focally positive for smooth muscle antigen (SMA) and negative for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor (HER-2/neu). Based on histological and immunohistochemical findings, the tumor was diagnosed as carcinosarcoma. Four of eighteen dissected axillary lymph nodes were positive for metastasis. Carcinosarcoma is often a triple-negative tumor. The lack of standardized treatment protocols frequently leads to poor prognosis and can pose a diagnostic dilemma; it should be part of the differential diagnosis for a case of carcinoma of the breast presenting as inflammatory carcinoma.

Carcinosarcoma of the breast: A case of breast conservation surgery and breast reconstruction

Breast carcinosarcoma is an extremely rare, clinically aggressive tumor, and no standard treatment has been established. We report about a 34-year-old woman presenting with a 2.5-cm-sized carcinosarcoma in her right breast. She presented to our hospital for examination of this mass. Ultrasonography showed a hypoechoic mass with partially irregular margins. Fine-needle aspiration cytology indicated malignancy. No enlarged lymph nodes or distant metastases were detected. We diagnosed right breast cancer and performed partial mastectomy, sentinel lymph node biopsy, and latissimus dorsi muscle flap transfer. Histological findings revealed that the tumor consisted of a mixture of an epithelial component and a mesenchymal component. The final diagnosis was carcinosarcoma. After undergoing adjuvant chemotherapy and radiotherapy, the patient has had no recurrence, and her cosmesis is maintained. Clinical data of carcinosarcoma are insufficient. Breast conservation and reconstruction for carcinosarcoma may be suitable as local treatments; however, the most appropriate treatment method has not been established.

Genomic profiling of metaplastic breast carcinomas reveals genetic heterogeneity and relationship to ductal carcinoma

Metaplastic breast carcinomas comprise a histologically heterogenous group of tumors. Although most are triple (estrogen/progesterone receptor, HER2) negative, these rare tumors are clinicopathologically distinct from other triple negative carcinomas and may be aggressive with worse chemotherapy responses. On the other hand, metaplastic carcinomas are histologically diverse, which is reflected in gene expression differences among subtypes. Whether metaplastic carcinomas are genetically distinct from other triple negative cancers and whether genetic differences underlie histologic subtypes remains poorly understood. We sequenced 408 cancer-related genes in 28 metaplastic carcinomas, including chondroid matrix-producing carcinomas (n = 10), spindle cell carcinomas (n = 5), and carcinomas with squamous (n = 5), mixed spindle/squamous (n = 5), and mixed metaplastic (n = 3) differentiation. Metaplastic carcinomas were highly enriched for PIK3CA/PIK3R1 (61%) and Ras-Map kinase (25%) pathway aberrations compared to other triple negative carcinomas (TCGA dataset 14%, p < 0.001 and 7%, p = 0.005, respectively) and harbored a high frequency of TP53 (64%) and TERT promoter (25%) mutations, but this varied among subtypes. Chondroid-matrix producing carcinomas lacked PI-3 kinase and Ras-Map kinase aberrations and TERT promoter mutations, compared to 100%, 39%, and 39% of non-matrix-producing tumors, respectively. TERT promoter mutations were enriched (47%) in spindle cell carcinomas and tumors with squamous or spindle/squamous differentiation. Spindle cell carcinomas lacked TP53 mutations, in contrast to other subtypes (78%, p = 0.003). Separate analysis of paired ductal carcinoma in situ and metaplastic carcinoma revealed shared clonality in all cases (n = 8). Activating PI-3 kinase and Ras pathway mutations were early events, and inactivating mutations in tumor suppressors including RB1, CDKN2A, and TP53 were associated with invasion in individual cases. Metaplastic components of two tumors showed genetic progression from separately sequenced paired invasive ductal carcinoma. The findings suggest that metaplastic carcinomas are genetically distinct from other triple negative breast cancers and highlight genetic heterogeneity that broadly correlates with histologic subtype. Heterologous elements progress from associated ductal carcinoma.

Whole-Exome Sequencing of Metaplastic Breast Carcinoma Indicates Monoclonality with Associated Ductal Carcinoma Component

Purpose: Although most human cancers display a single histology, there are unusual cases where two or more distinct tissue types present within a primary tumor. One such example is metaplastic breast carcinoma, a rare but aggressive cancer with a heterogeneous histology, including squamous, chondroid, and spindle cells. Metaplastic carcinomas often contain an admixed conventional ductal invasive or in situ mammary carcinoma component, and are typically triple-negative for estrogen receptor, progesterone receptor, and HER-2 amplification/overexpression. An unanswered question is the origin of metaplastic breast cancers. While they may arise independently from their ductal components, their close juxtaposition favors a model that postulates a shared origin, either as two derivatives from the same primary cancer or one histology as an outgrowth of the other. Understanding the mechanism of development of these tumors may inform clinical decisions.Experimental Design: We performed exome sequencing for paired metaplastic and adjacent conventional invasive ductal carcinomas in 8 patients and created a pipeline to identify somatic variants and predict their functional impact, without having normal tissue. We then determined the genetic relationships between the histologically distinct compartments.Results: In each case, the tumor components have nearly identical landscapes of somatic mutation, implying that the differing histologies do not derive from genetic clonal divergence.Conclusions: A shared origin for tumors with differing histologies suggests that epigenetic or noncoding changes may mediate the metaplastic phenotype and that alternative therapeutic approaches, including epigenetic therapies, may be required for metaplastic breast cancers. Clin Cancer Res; 23(16); 4875-84. ©2017 AACR.

Diagnosis of Metaplastic Breast Carcinoma: Keratin OSCAR Versus Other Cytokeratins

Metaplastic breast carcinoma (MBC) is a heterogenous group of tumors that diverge from conventional glandular differentiation. The metaplastic component can be focal or may be present purely posing diagnostic challenges. Since MBC may show focal immunostaining or may even be negative for some cytokeratins (CK), different CKs are often needed to prove their epithelial origin. OSCAR is a relatively new broad-spectrum anti-CK antibody. Thirty MBC cases diagnosed at our institution were retrieved, including 7 spindle cell carcinomas. Representative slides were immunostained for CK-OSCAR, CK-AE1/AE3, CAM5.2, CK-903, and CK5/6. Nineteen spindle cell lesions were used as controls, including 6 malignant and 10 borderline phyllodes tumor, 1 inflammatory pseudotumor, 1 solitary fibrous tumor, and 1 nodular fasciitis case. All 30 cases (100%) of metaplastic carcinomas were positive for CK-OSCAR, compared with 27/30 (90%, P=0.076) for CK-AE1/AE3, 21/30 (70%, P≤0.01) for CK-903, 19/30 (63.3%, P≤0.01) for CAM5.2, and 15/30 (50%, P≤0.01) for CK5/6. All control cases were negative for CK-OSCAR. All 7 spindle cell carcinomas were also positive for CK-OSCAR (100%) compared with 6/7 (85.7%) for CK-AE1/AE3, 4/7 (57%) for CK-903, 3/7 (42.8%) for CAM5.2, and 2/7 (28.5%) for CK5/6. Our data show that CK-OSCAR is more sensitive than other individual CKs in diagnosing MBC. Coupled with high specificity, CK-OSCAR may potentially be used in lieu of a panel of CKs to identify the epithelial origin of these tumors, especially in spindle cell tumors. This is particularly useful in limited core biopsy specimens, to help guide treatment and simultaneously lower testing costs.

Metaplastic breast carcinoma: Analysis of 31 cases from a single institute

PURPOSE

Metaplastic carcinoma of the breast (MBC) accounts for less than 1% of all mammary tumors. This study aimed at revision of the clinico-pathological features, treatment strategy and outcome for MBC patients presented to the Kuwait Cancer Control Center to define the clinical behavior and prognostic factors of these neoplasms in our population.

PATIENT AND METHODS

Thirty-one patients were retrieved from our surgical pathology registry between January 2005 and December 2014. Medical records were revised regarding the clinico-pathological features and treatment outcome.

RESULTS

MBC represented 1% of our breast cancer patients. The median age was 50years (32-70years). Two patients presented with metastatic disease. Mastectomy was done for 24 patients and 7 had conservative surgery. The median tumor size at the time of surgery was 5.5cm (1.5-12cm). Axillary nodes were negative in 21 patients (N0), 5 patients were N1, 4 patients were N2 and one Nx. Three histological subtypes were presented: carcinosarcoma (7 cases), squamous cell carcinoma/IDC with squamous differentiation (15 cases), high grade IDC with metaplastic differentiation (9 cases). Immunohistochemically, 26 were negative hormone receptors and all were negative for Her2/neu overexpression. Chemotherapy was used in 28 patients, and adjuvant radiotherapy in 24 patients. The median follow-up was 47months (7-126months), six patients lost follow-up. The 5-year OS was 69% and 5-year PFS was 50%.

CONCLUSION

MBC is a rare entity among breast carcinoma in Kuwait. Most of the cases present with poor prognostic indicators and often show lack of expression of ER, PR and Her2/neu.

Metaplastic breast cancer: clinical overview and molecular aberrations for potential targeted therapy

Metaplastic breast cancer is a rare subtype of invasive mammary carcinoma, with an aggressive behavior and usually poor outcome. Responses to systemic chemotherapy are suboptimal compared to patients with standard invasive ductal carcinoma. Limited data are available in regards to best treatment modalities, including chemotherapy. This review gives an overview of metaplastic breast cancer and its clinical and pathologic characteristics, in addition to treatment strategies, clinical trials, and future directions.

Mixed epithelial and mesenchymal metaplastic carcinoma (carcinosarcoma) of the breast: a case report

Metaplastic breast carcinoma (MBC) is an uncommon malignancy characterized by the co-existence of two or more cellular types, commonly a mixture of epithelial and mesenchymal components. A case of a female patient aged 46 years with MBC (carcinosarcoma) is presented, including mammographic, ultrasonic, gross examination, and pathological findings. After undergoing modified radical mastectomy of the left breast and subsequent six courses of adjuvant chemotherapy and endocrine therapy, the patient is now doing well with no recurrence and metastasis. Conventional treatments for invasive ductal carcinoma (IDC) may appear to be less effective. Patients with MBC would be appropriate candidates for innovative or targeted therapy regimens.

EMT in carcinoma progression and dissemination: facts, unanswered questions, and clinical considerations

Over the past decade, much effort has been made to understand how cancers metastasize. In deciphering the metastatic process, a vast amount of work has focused on the role of the epithelial to mesenchymal transition (EMT), which, in experimental models, confers tumor cells with invasive and metastatic abilities, resistance to therapies, as well as cancer stem cell phenotype-properties that have a major impact on cancer prognosis. Searching "EMT and cancer" in PubMed retrieves thousands of original research articles, yet, we haven't answered the most basic question in the field: has EMT any relevance in human tumors?

Immunohistochemical features of claudin-low intrinsic subtype in metaplastic breast carcinomas

PURPOSE

The claudin-low molecular subtype of breast cancer includes triple negative invasive carcinomas, with a high frequency of metaplastic and medullary features. The aim of this study was to evaluate the immunohistochemistry expression of claudins in a series of metaplastic breast carcinomas. We also assessed other claudin-low features, such as the cancer stem cell-like and epithelial-to-mesenchymal transition phenotypes.

RESULTS

The majority of the cases showed weak or negative staining for membrane claudins expression. We found 76.9% (10/13) low expressing cases for claudin-1, 84.6% (11/13) for claudin-3 and claudin-4, and 92.3% (12/13) for claudin-7. Regarding the cancer stem cell marker ALDH1, 30.8% (4/13) showed positive staining. We also showed that the majority of the cases presented a CD44(+)CD24(-/low) phenotype, positivity for vimentin and lack of E-cadherin expression. Interestingly, these claudin-low molecular features were specific of the mesenchymal component of metaplastic breast carcinomas, since its frequency was very low in other breast cancer molecular subtypes, as luminal, HER2-overexpressing and non-metaplastic triple negative tumors.

CONCLUSIONS

The negative/low expression of claudins and E-cadherin, high levels of vimentin, and the breast cancer stem cell phenotype suggests that metaplastic breast carcinomas have similar features to the ones included in the claudin-low molecular subtype, specially their mesenchymal components.

Metaplastic breast carcinomas are enriched in markers of tumor-initiating cells and epithelial to mesenchymal transition

Metaplastic breast carcinomas constitute a distinct aggressive form of invasive breast cancer with histological evidence of epithelial to mesenchymal transition toward spindle, chondroid, or osseous cell types. During tumorigenesis, epithelial to mesenchymal transition promotes invasion and metastasis and has been linked to the presence of stem cells. We hypothesized that metaplastic carcinomas may express epithelial to mesenchymal transition markers and may be enriched in tumor-initiating cells specifically in the non-glandular metaplastic elements. In 27 primary metaplastic carcinomas of the breast we tested the expression of epithelial to mesenchymal transition inducers ZEB1 and E-cadherin and the presence of tumor-initiating cells by using aldehyde dehydrogenase-1 (ALDH-1) and CD44(+)/CD24(-/low) immunohistochemistry. Of the 27 metaplastic carcinomas, 20 (74%) had squamous and/or spindle areas and 7 (26%) had heterologous elements (6 chondroid and 1 osseous). ALDH-1-positive and CD44(+)/CD24(-/low)-expressing cells were detected in the non-glandular metaplastic components (Fisher's exact, P=0.0017). E-cadherin expression was reduced or absent (aberrant) in all metaplastic components whereas it was normal in the glandular areas. On the contrary, overexpression of ZEB1 was detected in 41% (11 of 27) of the non-glandular, metaplastic components, and in none of the glandular areas. The presence of tumor-initiating cells, aberrant E-cadherin, and ZEB1 upregulation was associated in over 90% of the spindle areas and heterologous elements (χ(2) test, P<0.05). We provide first in situ evidence that epithelial to mesenchymal transition inducers and tumor-initiating cells are present specifically in the non-glandular components of metaplastic carcinomas.

Metaplastic sarcomatoid carcinoma of the breast appears more aggressive than other triple receptor-negative breast cancers

Metaplastic sarcomatoid carcinoma (MSC) of the breast is usually triple receptor (ER, PR, and HER2) negative and is not currently recognized as being more aggressive than other triple receptor-negative breast cancers. We reviewed archival tissue sections from surgical resection specimens of 47 patients with MSC of the breast and evaluated the association between various clinicopathologic features and patient survival. We also evaluated the clinical outcome of MSC patients compared to a control group of patients with triple receptor-negative invasive breast carcinoma matched for patient age, clinical stage, tumor grade, treatment with chemotherapy, and treatment with radiation therapy. Factors independently associated with decreased disease-free survival among patients with stage I-III MSC of the breast were patient age > 50 years (P = 0.029) and the presence of nodal macrometastases (P = 0.003). In early-stage (stage I-II) MSC, decreased disease-free survival was observed for patients with a sarcomatoid component comprising ≥ 95% of the tumor (P = 0.032), but tumor size was the only independent adverse prognostic factor in early-stage patients (P = 0.043). Compared to a control group of triple receptor-negative patients, patients with stage I-III MSC had decreased disease-free survival (two-sided log rank, P = 0.018). Five-year disease-free survival was 44 ± 8% versus 74 ± 7% for patients with MSC versus triple receptor-negative breast cancer, respectively. We conclude that MSC of the breast appears more aggressive than other triple receptor-negative breast cancers.

Mixed epithelial/mesenchymal metaplastic carcinoma (carcinosarcoma) of the breast in BRCA1 carrier

This case report describes a 35-year-old woman who was diagnosed with mixed epithelial/mesenchymal metaplastic carcinoma (carcinosarcoma) of the breast. Genetic analysis of blood DNA revealed a common founder mutation, BRCA1 5382insC. Examination of microdissected tumor samples determined that both epithelial and mesenchymal components contained deletion of the wild-type BRCA1 allele. This report exemplifies that even very uncommon breast tumor types may develop through biallelic inactivation of BRCA1 gene, that has to be considered in the genetic testing settings.

Histogenesis of metaplastic breast carcinoma and axillary nodal metastases

A 40-year-old breast-feeding woman presented with left breast swelling. On physical examination a 7 cm mass was found in the breast. Because biopsy demonstrated malignant tissue, mastectomy with axillary nodal dissection was performed. Pathological findings were consistent with metaplastic breast carcinoma with nodal metastases. The primary tumor consisted of three types of invasion: ductal, squamous, and sarcomatous. Furthermore, three morphological transitions were observed: ductal-squamous, ductal-sarcomatous, and squamous-sarcomatous. Ductal-squamous (12/18 microscopy slides) and squamous-sarcomatous transitions (10/18) were more commonly observed than ductal-sarcomatous transition (3/18). Furthermore, immunohistochemistry showed loss of epithelial marker (cytokeratin) and acquisition of mesenchymal markers (vimentin and alpha-smooth muscle actin) in the sarcomatous component. These findings suggested that epithelial-mesenchymal transition had occurred in the tumor and that two pathways, ductal-squamous-sarcomatous and ductal-sarcomatous transition, were involved in progression of metaplastic breast carcinoma. The main pathway appeared to be ductal-squamous-sarcomatous transition. Regarding the nodal metastases, of 13 positive nodes, ductal, squamous, and sarcomatous components were observed in 13, seven, and two nodes, respectively. Moreover, as in the primary tumor, ductal-squamous and squamous-sarcomatous transitions were observed. This suggested that the ductal component metastasized to the nodes and that epithelial-mesenchymal transition subsequently occurred within the nodes.

Biphasic metaplastic sarcomatoid carcinoma of the breast: report of a case

A 69-year-old woman was admitted to our hospital with the complaint of a right breast mass. As a result of thorough examinations, she was diagnosed with breast cancer and underwent breast-conserving surgery. The pathological findings of the resected specimen showed that the tumor consisted of intermingled carcinomatous and sarcomatous components with a transition zone. On immunohistochemical study, the sarcomatous cells in this transition zone showed partial positive staining for CD10, the myoepithelial marker, suggesting that the myoepithelial cells had transformed into sarcoma, and then this biphasic tumor was formed. Finally, she was diagnosed with biphasic metaplastic sarcomatoid carcinoma of the breast. Biphasic metaplastic sarcomatoid carcinoma of the breast is a relatively rare but aggressive disease. The pathological diagnosis is often controversial, requiring detailed immunohistochemical analysis. We report our experience with a case of biphasic metaplastic sarcomatoid carcinoma of the breast.

Salivary gland carcinosarcoma: oligonucleotide array CGH reveals similar genomic profiles in epithelial and mesenchymal components

In this study, we present a case of parotid gland de novo carcinosarcoma. Salivary gland carcinosarcoma (or true malignant mixed tumor) is a rare biphasic neoplasm, composed of both malignant epithelial and malignant mesenchymal components. It is yet unclear whether these two phenotypes occur by collision of two independent tumors or if they are of clonal origin. To analyze the clonality of the different morphologic tumor components, oligonucleotide microarray-based comparative genomic hybridization (oaCGH) was performed on the carcinoma and the sarcoma entity separately. This technique enables a high-resolution, genome-wide overview of the chromosomal alterations in the distinct tumor elements. Analysis of both fractions showed a high number of DNA copy number changes. Losses were more prevalent than gains (82 and 49, respectively). The carcinomatous element displayed more chromosomal aberrations than the sarcomatous component. Specific amplifications of MUC20 (in mesenchymal element) and BMI-1 (in both elements) loci were observed. Overall homology between the two genomic profiles was 75%. DNA copy number profiles of the epithelial and mesenchymal components in this salivary gland carcinosarcoma displayed extensive overlap, indicating a monoclonal origin. Since losses are shared to a larger extent than gains, they seem to be more essential for initial oncogenic events. Furthermore, specific amplifications of a mucin and a Polycomb group gene imply these proteins in the tumorigenesis of carcinosarcomas.

A case of matrix-producing carcinoma of the breast

BACKGROUND

Matrix-producing carcinoma (MPC) of the breast is one variant type of metaplastic carcinoma. The cellular origin of MPC remains unclear. It has been suggested the tumor cells in MPC have the combined characteristics of both epithelial cells and mesenchymal cells. Several reports suggested that the tumor cells in MPC might originate from the myoepithelial cells, but others suggested the origin was basal-like cells.

CASE PRESENTATION

The patient was a 42-year-old Japanese female. A tumor of about 2 cm in diameter was noted in the right breast. CT revealed the circumference of the tumor to have a ring-like structure, and fine needle aspiration cytology indicated suspicion for malignancy. Breast-conserving surgery was performed. Histopathological studies showed carcinoma cells, having cuboidal to oval-shaped nucleus, were proliferating in cord-like and sheet-like structures in the periphery. In the central areas of the tumor, myxoedematous area was observed with cartilaginous matrix and necrosis. The diagnosis was a matrix-producing carcinoma. Immunohistochemical findings showed the tumor cells had the characteristics of both epithelial cells and mesenchymal cells, while being negative for estrogen receptor, progesterone receptor, Her2, myoepithelial cell markers and basal cell markers.

CONCLUSION

The findings for our present patient and many of the other MPC patients reported in the published literature indicate that this breast cancer has the properties of both epithelial cells and mesenchymal cells. In addition, there is a possibility that matrix-producing tumor cells of our present patient may have a feature of undifferentiated cells.

Sarcomatoid eccrine porocarcinoma: report of two cases and a review of the literature

Eccrine porocarcinoma is an uncommon sweat gland malignancy. To the best of our knowledge, there has been no report in the English literature of porocarcinoma with predominantly undifferentiated sarcomatous change. We present two cases of sarcomatoid eccrine porocarcinoma associated with a benign poroma. Case 1 pertained to an 82-year-old woman with an ulcerated chest wall tumor, and Case 2 was that of a 74-year-old woman who presented with an ulcerated plaque in the lower leg. Case 1 showed an unusual pseudo-angiosarcomatous morphology with spindle cells dissecting through collagen bundles and forming vascular like channels. Case 2 revealed high-grade malignant spindle cells with focal evidence of ductal differentiation. In both the cases, benign poromatous elements were histologically evident. Immunohistochemistry performed showed pancytokeratin positivity in spindle cells of both lesions. Epithelial membrane antigen and carcino-embryonic antigen positivity in the malignant ductal elements and focal smooth muscle actin staining of the spindle cells were demonstrated in Case 2. A brief review of relevant literature is presented.

Sarcomatoid Basal Cell Carcinoma—Predilection for Osteosarcomatous Differentiation

Primary cutaneous carcinomas rarely show heterologous malignant mesenchymal differentiation. We report 11 cases of sarcomatoid basal cell carcinoma (BCC) with osteosarcomatous differentiation. The patients (7 men and 4 women) ranged in age from 61 to 92 years (median 75 y). The tumors presented as exophytic nodules (0.3 to 7 cm) on the head (n=6), upper limb (n=3), and lower limb (n=2). All lesions were completely excised. Seven patients were alive without evidence of disease (follow-up interval 5 to 24 mo) and 1 patient died of unrelated causes at 7 months without evidence of disease. On histology, the tumors were dermal in location with 2 cases showing focal subcutaneous involvement. Ten tumors were well-circumscribed and 1 tumor showed focally infiltrative edges. Ten tumors revealed conventional BCC associated with varying proportions of osteosarcomatous and undifferentiated sarcomatous stroma. Transition from neoplastic epithelial to mesenchymal cells was seen in 8 cases. One case showed a purely osteoclastic giant cell rich malignant mesenchyme, interpreted as representing early stages of osteosarcomatous transformation. Previously unreported in sarcomatoid BCC, the mesenchymal component of another two cases displayed predominant malignant giant cell tumor like areas and 1 further case disclosed areas reminiscent of telangiectatic osteosarcoma. Pancytokeratins (AE1/3 and MNF116) and smooth muscle actin stained occasional undifferentiated sarcomatous cells in 2 and 3 tumors, respectively. MNF116 and EMA were focally positive in osteosarcomatous tumor cells of 1 case. Although the follow-up interval is short, our data suggest an excellent prognosis for polypoid and exophytic sarcomatoid BCC after complete surgical resection.

Biphasic metaplastic sarcomatoid carcinoma of the breast

BACKGROUND

Breast biphasic metaplastic sarcomatoid carcinoma (MSC) is rare and aggressive. We analyzed 100 patients treated at M. D. Anderson Cancer Center (MDACC) with 213 MSC and 98 carcinosarcoma patients identified through the Surveillance, Epidemiology and End-Results (SEER) database to describe clinical and pathologic characteristics.

PATIENTS AND METHODS

We searched the MDACC (1985-2001) and SEER databases (1988-2001) for breast MSC and carcinosarcoma patients.

RESULTS

We identified 100 MDACC MSC patients: 66% had node-negative disease and 6% distant metastases at presentation. Median recurrence-free survival (RFS) of 94 patients with stages I-III disease was 74 months (range 3-74), with 52% 5-year RFS [95% confidence interval (CI) 0.42-0.63]. Median overall survival in these patients was not reached, with 64% 5-year survival (95% CI 0.54-0.75). The initial stage of the tumor, but not use of adjuvant chemo- or radiotherapy, had a strong association with outcome. The pathologic complete response rate to neoadjuvant chemotherapy was 10%. Median survival from the time of recurrent disease was 14 months (range 1-55). Tumors were usually hormone receptor- and HER2/neu-negative. SEER data were consistent with MDACC findings.

CONCLUSIONS

Breast MSC and carcinosarcoma are aggressive, treatment-refractory tumors with shared clinical features and outcome similar to poorly differentiated receptor-negative adenocarcinomas. New therapeutic agents are needed.

p63 Expression in Breast Cancer

p63, a member of the p53 gene family, is involved in cellular differentiation and is expressed in the nuclei of myoepithelial cells of normal breast ducts and lobules. Although p63 has been reported in metaplastic carcinomas of the breast, its expression pattern in breast carcinomas and sarcomas has not been fully characterized, and its potential diagnostic utility has not been defined. In this study, we determined p63 expression in a large number of breast carcinomas, including metaplastic carcinomas, and in Phyllodes tumors and sarcomas. We examined 189 invasive breast carcinomas, including 15 metaplastic carcinomas, as well as 10 Phyllodes tumors, and 5 pure sarcomas of the breast for pattern and intensity of p63 staining using an anti-p63 antibody (clone 4A4, Neomarkers). p63 was strongly expressed in 13 of 15 metaplastic carcinomas (86.7%). p63 was positive in all the metaplastic carcinomas with spindle cell and/or squamous differentiation (12 of 12), and in 1 of 3 metaplastic carcinomas with cartilage foci. In stark contrast, only 1 of 174 (0.6%) nonmetaplastic invasive carcinomas was positive for p63. All Phyllodes tumors and sarcomas were consistently negative for p63 expression. The sensitivity and specificity of p63 as a diagnostic marker for metaplastic carcinoma was 86.7% and 99.4%, respectively. We propose the inclusion of p63 as part of the diagnostic workup of challenging spindle cell tumors of the breast as a highly specific marker for metaplastic carcinomas.

Growth and differentiation of progenitor/stem cells derived from the human mammary gland

Estrogen is necessary for the full development of the mammary gland and it is also involved in breast cancer development. We set out to identify and characterise progenitor/stem cells in the human mammary gland and to explore the role of estrogen in their proliferation and differentiation. Three candidate stem cell populations were isolated: double positive (DP) cells co-expressed the luminal and myoepithelial markers, EMA and CALLA, respectively, whereas double negative (DN) cells did not express these cell surface markers; side population (SP) cells were characterised by their differential ability to efflux the dye Hoechst 33342. The ABC transporter, breast cancer resistance protein (BCRP) was more highly expressed in SP cells than in non-SP cells and a specific BCRP inhibitor, Ko143, reduced SP formation, suggesting that BCRP confers the SP phenotype in mammary epithelial cells, as has been demonstrated in other tissues. Interestingly, SP cells were double negative for the EMA and CALLA antigens and therefore represent a separate and distinct population to DP cells. Single cell multiplex RT-PCR indicated that the SP and DN cells do not express detectable levels of ERalpha or ERbeta, suggesting that estrogen is not involved in their proliferation. DP cells expressed ERalpha but at a lower level than differentiated luminal cells. These findings invoke a potential strategy for the breast stem/progenitor cells to ignore the mitogenic effects of estrogen. All three cell populations generated mixed colonies containing both luminal and myoepithelial cells from a single cell and therefore represent candidate multipotent stem cells. However, DN cells predominately generated luminal colonies and exhibited a much higher cloning efficiency than differentiated luminal cells. Further characterisation of these candidate progenitor/stem cells should contribute to a better understanding of normal mammary gland development and breast tumorigenesis.

Production of spindle cell carcinoma by transduction of H-Ras 61L into immortalized human mammary epithelial cells

Human mammary epithelial cells (HMEC) were immortalized by serial passaging through senescence (M0) and subsequent transduction with the catalytic subunit of the human telomerase gene (hTERT). These cells acquired multiple non-random cytogenetic abnormalities with lengthy passaging in vitro, but are still not tumorigenic in irradiated nude mice and cannot grow in soft agar. Transduction, of late passage immortal HMEC from a single donor, with a retroviral vector containing the mutant autoactive H-Ras 61L gene, enabled immortal HMEC to acquire anchorage independent growth properties. Three colonies were picked and all three were found to be tumorigenic. One colony exclusively produced epithelial tumors in nude mice, but the other two colonies gave rise exclusively to malignancies in which the cells displayed a spindle morphology. In this paper we describe the characteristics of the tumors arising from one of these 'spindle colonies'. These tumors were strongly positive for vimentin staining and virtually negative for pan-cytokeratin staining, on immunohistochemistry. Cytogenetic analysis of the cells derived from these tumors confirmed that they were derived from the original cultured, immortalized mammary cells. We conclude that the HMEC have undergone metaplastic transformation due to the high levels of H-Ras 61L and telomerase activity that they display, and the derived tumors are best described as spindle cell carcinomas.

Molecular defects in the pathogenesis of pituitary tumours

The majority of pituitary adenomas are trophically stable and change relatively little in size over many years. A comparatively small proportion behave more aggressively and come to clinical attention through inappropriate hormone secretion or adverse effects on surrounding structures. True malignant behaviour with metastatic spread is very atypical. Pituitary adenomas that come to surgery are predominantly monoclonal in origin and roughly half are aneuploid, indicating either ongoing genetic instability or transition through a period of genetic instability at some time during their development. Few are associated with the classical mechanisms of tumour formation but it is generally believed that the majority harbour quantitative if not qualitative differences in molecular composition compared to the normal pituitary. Despite their prevalence and the ready availability of biopsy material, at the present time, the precise molecular pathogenesis of the majority of pituitary adenomas remains unclear. This review summarizes current thinking.

Epithelial to mesenchymal transition in human breast cancer can provide a nonmalignant stroma

A breast carcinoma biopsy showed cytochemical evidence of epithelial mesenchymal transition and an alpha-smooth muscle actin-positive stromal reaction. To study the lineage, and the nature of the cells in the stromal reaction, we derived a novel cell line, HBFL-1, from the explanted biopsy. HBFL-1 cells are immortal and exhibit a shared non-random X-chromosome inactivation pattern with the epithelial tumor of origin. Yet they closely resemble normal, finite-life-span fibroblasts by morphology, lack of tumor formation in nude mice, marker expression profile, protein pattern using two-dimensional gel electrophoresis and the ability to undergo myofibroblast conversion. HBFL-1 interacts reciprocally with tumor cells in collagen gel to induce activation of MMP2, leading to tumor-like behavior of epithelial colonies. In vivo, HBFL-1 cells resembled normal-derived myofibroblasts and conferred a significant 3.5- to 7-fold increase in MCF-7 tumor size in nude mice. However, that they were indeed not normal fibroblasts was revealed by residual keratin expression and formation of epithelial microfoci in a reconstituted basement membrane and in nude mice. We conclude that breast cancer can generate its own nonmalignant stroma and that one function for this is that of a reciprocal interaction with epithelial tumor cells to facilitate tumor growth.

Analysis of the progression of fibroepithelial tumours of the breast by PCR-based clonality assay

Fibroadenoma and phyllodes tumour of the breast are both fibroepithelial tumours. Although progression to epithelial malignancy has been described, the behaviour of most fibroadenomas is benign. Phyllodes tumours, on the other hand, can display locally destructive growth and can even metastasize. A relationship between the two tumours has been suggested in the literature. This study investigated the clonality of both the stroma and the epithelium of these fibroepithelial tumours and attempted to construct a model in which fibroadenoma can progress in both an epithelial and a stromal direction. Fibroadenomas (n=25) and phyllodes tumours (n=12) were selected for analysis. Tissue was microdissected and analysed for clonality using a polymerase chain reaction (PCR)-based assay targeted at an X-linked polymorphic marker, the human androgen receptor gene (HUMARA). Nineteen fibroadenomas and nine phyllodes tumours could be analysed. Normal-appearing epithelium, hyperplastic epithelium, and stroma removed from fibroadenomas were polyclonal. As expected, carcinoma in situ (CIS) removed from four fibroadenomas was monoclonal. Three areas of apparent stromal expansion within fibroadenoma were monoclonal, suggesting stromal progression. Mostly, the stroma of phyllodes tumours was monoclonal and the epithelium polyclonal. In two cases, however, the epithelium seemed to be monoclonal, whereas in three other cases the stromal component was polyclonal. These findings indicate that fibroadenoma can progress in an epithelial direction to CIS and in a stromal direction to phyllodes tumour.

Metachronous bilateral mammary metaplastic and infiltrating duct carcinomas: a molecular study for clonality

Mammary metaplastic carcinoma is uncommon. In this study, both carcinoma and sarcoma components of a metaplastic carcinoma and a subsequent metachronous contralateral infiltrating ductal carcinoma were analyzed by microsatellite analysis for the loss of heterozygosity (LOH) patterns at multiple sites on chromosome arms 3p, 6q, 8, 9p, 11, 13q, 14q, 16q, and 17p. The LOH patterns between the carcinoma and sarcoma components in the first tumor were similar, indicating clonality. The LOH patterns between the first and second tumors were different at all chromosome arms, indicating different clonality and a second primary. We demonstrated a second primary carcinoma in a patient with previous metaplastic carcinoma rather than a metastasis with carcinoma component only.

Cytogenetic clues to breast carcinogenesis

The somatic mutation theory of cancer maintains that tumorigenesis is driven by genetic alterations, many of which are visible cytogenetically. We have examined breast cancer by chromosome banding analysis after short-term culturing of tumor cells and here review our findings in 322 karyotypically abnormal samples obtained since 1992 from 256 patients. The screening capabilities of this technique enabled us to identify several cytogenetic subgroups of breast cancer, to study the intratumor heterogeneity of breast carcinomas, and to compare primary tumors with their metastases. Using chromosome abnormalities as clonality markers, we could determine on an individual basis when multiple, ipsilateral or bilateral breast, tumors were independent de novo carcinomas and when they resulted from the spreading of a single malignant clone within one breast or from one breast to the other. The distribution of chromosomal breakpoints and genomic gains and losses is clearly nonrandom in breast cancer, something that can guide further investigations using molecular methods. Based on the total dataset, we propose a multipathway model of mammary carcinogenesis that takes into consideration the genetic heterogeneity revealed by the karyotypic findings and review the karyotypic-pathologic correlations and the possible clinical applications of the cytogenetic knowledge.

Monoclonality of endocrine tumours: What does it mean?

It is believed and hoped that clonality assignment of tumours predicts long-term behaviour, narrows the search for the putative pathogenic event or events, identifies the extent of involvement of surrounding and distant tissues and assesses the completeness of surgical clearance. It should define optimal therapeutic strategies, such as gene therapy, and the most fruitful directions for research. Because the histological characteristics that are central to establishing prognosis in most neoplasms are of limited value in endocrine tumours, the benefits of interpretation of clonality are potentially even more valuable and far-reaching in these tissues. So, can clonality be accurately defined and, if it can, can the distinction between a polyclonal expansion of cells that are simply 'obeying orders' and the presumed progeny of a single anarchic mutant be usefully made? This review comes to the conclusion that the answer is 'probably not'.

The clonal origin and clonal evolution of epithelial tumours

While the origin of tumours, whether from one cell or many, has been a source of fascination for experimental oncologists for some time, in recent years there has been a veritable explosion of information about the clonal architecture of tumours and their antecedents, stimulated, in the main, by the ready accessibility of new molecular techniques. While most of these new results have apparently confirmed the monoclonal origin of human epithelial (and other) tumours, there are a significant number of studies in which this conclusion just cannot be made. Moreover, analysis of many articles show that the potential impact of such considerations as patch size and clonal evolution on determinations of clonality have largely been ignored, with the result that a number of these studies are confounded. However, the clonal architecture of preneoplastic lesions provide some interesting insights --many lesions which might have been hitherto regarded as hyperplasias are apparently clonal in derivation. If this is indeed true, it calls into some question our hopeful corollary that a monoclonal origin presages a neoplastic habitus. Finally, it is clear, for many reasons, that methods of analysis which involve the disaggregation of tissues, albeit microdissected, are far from ideal and we should be putting more effort into techniques where the clonal architecture of normal tissues, preneoplastic and preinvasive lesions and their derivative tumours can be directly visualized in situ.

Synovial sarcoma specific translocation associated with both epithelial and spindle cell components

The biphasic subtype of synovial sarcoma consists of both epithelial and spindle cell components. To address the relationship between the different cellular components found in synovial sarcoma, we deduced the presence of the synovial sarcoma-specific der(X)t(X;18)(p11.2;q11.2), and involvement of the SSX1 gene in both the epithelial/glandular and spindle cell components of 3 biphasic synovial sarcomas with wide ranging proportions of each of the 2 elements. This has been achieved using a 2-color fluorescence in situ hybridization (FISH) methodology that we had developed recently for analysis paraffin-embedded material. The presence of the rearrangement could be deduced in histologically defined regions and the results showed clearly that the rearrangement was present in both cellular components. This finding provides direct genetic evidence for biphasic synovial sarcomas being clonal and truly biphasic.