Markers of epithelial-mesenchymal transition and epithelial differentiation in sarcomatoid carcinoma: utility in the differential diagnosis with sarcoma

Clinicopathological features and differential diagnosis of gastric pleomorphic giant cell carcinoma

The aim of this study was to investigate the clinicopathological features and differential diagnosis of gastric pleomorphic giant cell carcinoma. Histopathology, immunohistochemistry, and human epidermal growth factor receptor 2 (HER2) gene testing were conducted for seven cases of gastric pleomorphic giant cell carcinoma. In histomorphological terms, all seven cases involved pleomorphic giant cell carcinoma, accounting for more than 10% of the entire tumor, with pleomorphic spindle cells and giant cells mixed with various histomorphological structures of adenocarcinoma with high, intermediate, and low differentiation. There was large heterogeneity in the HER2 protein expression and HER2 gene amplification in the gastric pleomorphic giant cell carcinoma, and both levels of HER2 were focal in three cases, accounting for 42.9% (3/7). The mismatch repair gene proteins MLH1, MSH2, PMS2, and MSH6 were positive. Routine immunohistochemical markers, i.e., pan-cytokeratin, epithelial membrane antigen, villin, caudal-type homeobox 2, E-cadherin, and p53, were positive in the gastric pleomorphic giant cell carcinoma, while vimentin, calponin, smooth muscle actin, nestin, S-100, cluster of differentiation (CD) 99, desmin, and CD34 were focally expressed in both the spindle and the giant cells, with Ki-67-positive cells accounting for 70-80%. Gastric pleomorphic giant cell carcinoma presents multiple histomorphological features and is easily confused with various tumors. Clarifying the histopathological features of this type of tumor is important for differential diagnosis and precise treatment.

How does plasticity of migration help tumor cells to avoid treatment: Cytoskeletal regulators and potential markers

Tumor shrinkage as a result of antitumor therapy is not the only and sufficient indicator of treatment success. Cancer progression leads to dissemination of tumor cells and formation of metastases - secondary tumor lesions in distant organs. Metastasis is associated with acquisition of mobile phenotype by tumor cells as a result of epithelial-to-mesenchymal transition and further cell migration based on cytoskeleton reorganization. The main mechanisms of individual cell migration are either mesenchymal, which depends on the activity of small GTPase Rac, actin polymerization, formation of adhesions with extracellular matrix and activity of proteolytic enzymes or amoeboid, which is based on the increase in intracellular pressure caused by the enhancement of actin cortex contractility regulated by Rho-ROCK-MLCKII pathway, and does not depend on the formation of adhesive structures with the matrix, nor on the activity of proteases. The ability of tumor cells to switch from one motility mode to another depending on cell context and environmental conditions, termed migratory plasticity, contributes to the efficiency of dissemination and often allows the cells to avoid the applied treatment. The search for new therapeutic targets among cytoskeletal proteins offers an opportunity to directly influence cell migration. For successful treatment it is important to assess the likelihood of migratory plasticity in a particular tumor. Therefore, the search for specific markers that can indicate a high probability of migratory plasticity is very important.

First report on establishment and characterization of a carcinosarcoma tumour cell line model of the bladder

Carcinosarcoma of the urinary bladder is a very rare and aggressive subtype of bladder cancer with poor prognosis. Characteristically carcinosarcomas exhibit biphasic nature with both epithelial and mesenchymal differentiation. Limited information is available regarding its clinical features and appropriate treatments due to its rarity. Development of tumour models can further our understanding of bladder carcinosarcoma. We report establishment and characterization of the first-ever bladder carcinosarcoma cell line MaS-3. It is established by the outgrow method from 86 year-old caucasian male who underwent a radical pelvic resection after neoadjuvant radiotherapy. MaS-3 showed carcinosarcoma profile with high conformity with to the original tumour in terms of immunocytochemistry. Proteome analysis also aligned the MaS-3 cell line with the carcinosarcoma specimen rather than corresponding non-malignant tissue. Chemotherapy sensitivity testing revealed a great sensitivity of MaS-3 growth to 5-Fluorouracil, Gemcitabine and Cisplatin, with almost no impact of Irinotecan. Additionally, the suitability of MaS-3 for 3D in vitro experiments was also demonstrated. The newly established cell line MaS-3 shows typical characteristics of the tumour and may thus be a useful in vitro model system for studying the tumour biology and developing future of treatments of this rare but very aggressive entity.

LncRNA HOXA11-AS regulates the proliferation and epithelial to mesenchymal transition of human skin cancer cells

LncRNA HOXA11-AS functions as regulator of tumorigenesis of several human cancers. The present study was intended to explore its regulatory control in human skin cancer with emphasis on understanding the underlying molecular mechanism. The results showed significant (P < 0.05) upregulation of lncRNA HOXA11-AS transcript levels in human skin cancer tissues and cell lines. The knockdown of HOXA11-AS significantly (P < 0.05) inhibited the proliferation and colony formation of A375 and HMCB skin cancer cells. Flow cytometry showed that HOXA11-AS knockdown triggered arrest of the A375 and HMCB cells at G₂/M check point of cell cycle by inhibiting the expression of cyclin B1. Additionally, western blot analysis showed that HOXA11-AS knockdown resulted in the deactivation of PI3K/AKT/mTOR signaling pathway. The silencing of HOXA11-AS significantly (P < 0.05) inhibited the migration and invasion of the A375 and HMCB skin cancer cells. This was also accompanied by increase in E-cadherin and decrease in N-cadherin expression. Collectively, the results indicate that lncRNA HOXA11-AS regulates the proliferation, migration and invasion of human skin cancer and may exhibit therapeutic potential in the treatment of skin cancer.

Actin cytoskeleton in mesenchymal-to-amoeboid transition of cancer cells

During development of metastasis, tumor cells migrate through different tissues and encounter different extracellular matrices. An ability of cells to adapt mechanisms of their migration to these diverse environmental conditions, called migration plasticity, gives tumor cells an advantage over normal cells for long distant dissemination. Different modes of individual cell motility-mesenchymal and amoeboid-are driven by different molecular mechanisms, which largely depend on functions of the actin cytoskeleton that can be modulated in a wide range by cellular signaling mechanisms in response to environmental conditions. Various triggers can switch one motility mode to another, but regulations of these transitions are incompletely understood. However, understanding of the mechanisms driving migration plasticity is instrumental for finding anti-cancer treatment capable to stop cancer metastasis. In this review, we discuss cytoskeletal features, which allow the individually migrating cells to switch between mesenchymal and amoeboid migrating modes, called mesenchymal-to-amoeboid transition (MAT). We briefly describe main characteristics of different cell migration modes, and then discuss the triggering factors that initiate MAT with special attention to cytoskeletal features essential for migration plasticity.

An Algorithmic Immunohistochemical Approach to Define Tumor Type and Assign Site of Origin

Immunohistochemistry represents an indispensable complement to an epidemiology and morphology-driven approach to tumor diagnosis and site of origin assignment. This review reflects the state of my current practice, based on 15-years' experience in Pathology and a deep-dive into the literature, always striving to be better equipped to answer the age old questions, "What is it, and where is it from?" The tables and figures in this manuscript are the ones I "pull up on the computer" when I am teaching at the microscope and turn to myself when I am (frequently) stuck. This field is so exciting because I firmly believe that, through the application of next-generation immunohistochemistry, we can provide better answers than ever before. Specific topics covered in this review include (1) broad tumor classification and associated screening markers; (2) the role of cancer epidemiology in determining pretest probability; (3) broad-spectrum epithelial markers; (4) noncanonical expression of broad tumor class screening markers; (5) a morphologic pattern-based approach to poorly to undifferentiated malignant neoplasms; (6) a morphologic and immunohistochemical approach to define 4 main carcinoma types; (7) CK7/CK20 coordinate expression; (8) added value of semiquantitative immunohistochemical stain assessment; algorithmic immunohistochemical approaches to (9) "garden variety" adenocarcinomas presenting in the liver, (10) large polygonal cell adenocarcinomas, (11) the distinction of primary surface ovarian epithelial tumors with mucinous features from metastasis, (12) tumors presenting at alternative anatomic sites, (13) squamous cell carcinoma versus urothelial carcinoma, and neuroendocrine neoplasms, including (14) the distinction of pheochromocytoma/paraganglioma from well-differentiated neuroendocrine tumor, site of origin assignment in (15) well-differentiated neuroendocrine tumor and (16) poorly differentiated neuroendocrine carcinoma, and (17) the distinction of well-differentiated neuroendocrine tumor G3 from poorly differentiated neuroendocrine carcinoma; it concludes with (18) a discussion of diagnostic considerations in the broad-spectrum keratin/CD45/S-100-"triple-negative" neoplasm.

Sarcomatoid carcinomas of the gallbladder: clinicopathologic characteristics

Sarcomatoid carcinomas recently came into the spotlight through genetic profiling studies and also as a distinct model of epithelial-mesenchymal transition. The literature on sarcomatoid carcinomas of gallbladder is limited. In this study, 656 gallbladder carcinomas (GBC) were reviewed. Eleven (1.7%) with a sarcomatoid component were identified and analyzed in comparison with ordinary GBC (O-GBC). Patients included 9 females and 2 males (F/M = 4.5 vs. 3.9) with a mean age-at-diagnosis of 71 (vs. 64). The median tumor size was 4.6 cm (vs. 2.5; P = 0.01). Nine patients (84%) presented with advanced stage (pT3/4) tumor (vs. 48%). An adenocarcinoma component constituting 1-75% of the tumor was present in nine, and eight had surface dysplasia/CIS; either in situ or invasive carcinoma was present in all cases. An intracholecystic papillary-tubular neoplasm was identified in one. Seven showed pleomorphic-sarcomatoid pattern, and four showed subtle/bland elongated spindle cells. Three had an angiosarcomatoid pattern. Two had heterologous elements. One showed few osteoclast-like giant cells, only adjacent to osteoid. Immunohistochemically, vimentin, was positive in six of six; P53 expression was > 60% in six of six, keratins in six of seven, and p63 in two of six. Actin, desmin, and S100 were negative. The median Ki67 index was 40%. In the follow-up, one died peri-operatively, eight died of disease within 3 to 8 months (vs. 26 months median survival for O-GBC), and two were alive at 9 and 15 months. The behavior overall was worse than ordinary adenocarcinomas in general but was not different when grade and stage were matched. In summary, sarcomatoid component is identified in < 2% of GBC. Unlike sarcomatoid carcinomas in the remainder of pancreatobiliary tract, these are seldom of the "osteoclastic" type and patients present with large/advanced stage tumors. Limited data suggests that these tumors are aggressive with rapid mortality unlike pancreatic osteoclastic ones which often have indolent behavior.

Evaluation of cytokeratin 19 as a prognostic tumoral and metastatic marker with focus on improved detection methods

In the last few years, there has been a growing interest in Cytokeratin 19 (CK19) studies in the cancer research field. CK19 belongs to the Type I CKs, serves as a useful research tool in prognosis, diagnosis, and management of the tumors. In this paper, we dissect the metastatic potential of CK19, its relation with cancer stem cells and retinal epithelial cells behavior, its application as a tumor marker and its role among 30 cancers such as thyroid, thoracic, lung, pancreatic, cervical, colorectal, and so forth. CK19 expressed in several cancer types because of its metastatic potential. This paper also presents modified detection methods of CK19 in disseminated tumor cells.

Pulmonary sarcomatoid carcinoma: University of Cincinnati experience

Objectives

To review the outcomes of treatment in patients with pulmonary sarcomatoid carcinoma (PSC) treated at the University of Cincinnati Medical Center (UCMC).

Results

There was no significant difference in survival of patients treated with chemotherapy alone (median, 256 days) compared to patients not undergoing treatment (median, 205.5 days). Patients who underwent surgery and adjuvant chemotherapy showed a trend in improvement of survival (median, 457.6 days). Patients requiring only surgery had the longest OS of 713.5 days.

Conclusions

Systemic chemotherapy alone did not improve survival in patients with PSC. Surgery provides the greatest overall survival benefit and adjuvant chemotherapy may also improve survival.

Methods

From 2000 to 2014, twenty-five patients with pathologically confirmed PSC were treated at UCMC. The outcomes were retrospectively analyzed by treatment with overall survival (OS) as the endpoint.

The pVHL172 isoform is not a tumor suppressor and up-regulates a subset of pro-tumorigenic genes including TGFB1 and MMP13

The von Hippel-Lindau (VHL) tumor suppressor gene is often deleted or mutated in ccRCC (clear cell renal cell carcinoma) producing a non-functional protein. The gene encodes two mRNA, and three protein isoforms (pVHL₂₁₃, pVHL₁₆₀ and pVHL₁₇₂). The pVHL protein is part of an E3 ligase complex involved in the ubiquitination and proteasomal degradation of different proteins, particularly hypoxia inducible factors (HIF) that drive the transcription of genes involved in the regulation of cell proliferation, angiogenesis or extracellular matrix remodelling. Other non-canonical (HIF-independent) pVHL functions have been described. A recent work reported the expression of the uncharacterized protein isoform pVHL₁₇₂ which is translated from the variant 2 by alternative splicing of the exon 2. This splice variant is sometimes enriched in the ccRCCs and the protein has been identified in the respective samples of ccRCCs and different renal cell lines. Functional studies on pVHL have only concerned the pVHL₂₁₃ and pVHL₁₆₀ isoforms, but no function was assigned to pVHL₁₇₂. Here we show that pVHL₁₇₂ stable expression in renal cancer cells does not regulate the level of HIF, exacerbates tumorigenicity when 786-O-pVHL₁₇₂ cells were xenografted in mice. The pVHL₁₇₂-induced tumors developed a sarcomatoid phenotype. Moreover, pVHL₁₇₂ expression was shown to up regulate a subset of pro-tumorigenic genes including TGFB1, MMP1 and MMP13. In summary we identified that pVHL₁₇₂ is not a tumor suppressor. Furthermore our findings suggest an antagonistic function of this pVHL isoform in the HIF-independent aggressiveness of renal tumors compared to pVHL₂₁₃.

Micropapillary colorectal carcinoma: clinical, pathological and molecular properties, including evidence of epithelial-mesenchymal transition

AIMS

Colorectal carcinoma (CRC) with micropapillary (MP) features has only been described recently and is still being characterized.

METHODS AND RESULTS

We reviewed the clinicopathological and molecular features of 42 CRC with MP features. Twenty-nine cases were also evaluated for immunohistochemical evidence of epithelial-mesenchymal transition (EMT). The extent of MP features within our cohort ranged from 5% (13 cases) to 100% (one case). Twenty-seven cases featured prominent cribriforming with dirty necrosis in the non-MP component; nine displayed mucinous features. Twenty-four of 29 cases (83%) demonstrated evidence of EMT. Thirty-six cases (86%) showed advanced T-category (pT3 or pT4), 31 (74%) had lymph node metastases and 23 (55%) had distant metastases. Median overall follow-up was 36 months. Seventeen patients (40%) died of disease, with median survival of 23 months. Mutations were seen in 17 of 31 tested cases (55%), including 11 KRAS mutations and four BRAF V600E mutations. Microsatellite instability testing was performed on 21 cases; all were microsatellite-stable. Compared to a cohort of 972 conventional CRC, MP CRC was more likely to present as stage IV disease (P < 0.001), but patients with MP CRC showed no significant differences in overall survival after adjusting for stage.

CONCLUSIONS

Micropapillary features in CRC portend a high likelihood of advanced local disease and distant metastases. MP CRC is often associated with a cribriform pattern elsewhere in the tumour and cystic nodal metastases with prominent necrosis. They also show frequent mutations in KRAS and BRAF. Immunohistochemical evidence of EMT is common in MP CRC.

Unclassified sarcomas: a study to improve classification in a cohort of Golden Retriever dogs

Morphologically, canine soft-tissue sarcomas (STSs) resemble human STSs. In humans, proper classification of STSs is considered essential to improve insight in the biology of these tumors, and to optimize diagnosis and therapy. To date, there is a paucity of data published on the significance of detailed classification of STSs in the dog. We revised a cohort (n = 110) of proliferative lesions obtained from a study in Golden Retrievers that were considered "soft tissue sarcoma, not otherwise specified or of uncertain subtype" in order to optimize the diagnoses of these lesions. The criteria according to the veterinary WHO classification, recent veterinary literature, and the WHO classification for humans were applied. Revision was initially based on morphologic characteristics of hematoxylin and eosin-stained histologic sections of the neoplasms. If considered necessary (n = 76), additional immunohistochemistry was applied to aid characterization. The diagnosis of STS was confirmed in 75 neoplasms (68%). Of this group, diagnosis of a specific subtype of the STSs was possible in 58 neoplasms. Seven neoplasms had morphologic characteristics that were suggestive for sarcoma subtypes only described in the WHO classification for humans. Seventeen neoplasms remained "unclassified STSs." Thirty-one lesions (28%) were diagnosed "neoplasm, not being STS." Four lesions (4%) were considered nonneoplastic. Because incorrect classification of a tumor could lead to inappropriate therapeutic intervention and prognostication, the results of our study clearly illustrate the importance of revision and further diagnosis of "unclassified STSs" in dogs.

Plasticity of Cancer Cell Invasion-Mechanisms and Implications for Therapy

Cancer cell migration is a plastic and adaptive process integrating cytoskeletal dynamics, cell-extracellular matrix and cell-cell adhesion, as well as tissue remodeling. In response to molecular and physical microenvironmental cues during metastatic dissemination, cancer cells exploit a versatile repertoire of invasion and dissemination strategies, including collective and single-cell migration programs. This diversity generates molecular and physical heterogeneity of migration mechanisms and metastatic routes, and provides a basis for adaptation in response to microenvironmental and therapeutic challenge. We here summarize how cytoskeletal dynamics, protease systems, cell-matrix and cell-cell adhesion pathways control cancer cell invasion programs, and how reciprocal interaction of tumor cells with the microenvironment contributes to plasticity of invasion and dissemination strategies. We discuss the potential and future implications of predicted "antimigration" therapies that target cytoskeletal dynamics, adhesion, and protease systems to interfere with metastatic dissemination, and the options for integrating antimigration therapy into the spectrum of targeted molecular therapies.

Sarcomatoid Carcinoma of the Urinary Bladder

Sarcomatoid carcinoma of the urinary bladder (SCUB) is a rare and aggressive subtype of bladder cancer that has a poor prognosis. Limited information is available regarding its clinical features and appropriate treatments. A systematic literature search for published reports on SCUB was performed in the MEDLINE database using the key words "bladder cancer," "sarcomatoid carcinoma," and "carcinosarcoma.". The search resulted in the identification of 276 reports published from January 1960 to January 2014, of which 40 were ultimately included in the present review. No prospective study or clinical trial of SCUB was reported in English language studies. Of these studies, 2 cancer registry studies and 13 large case series, which had included ≥ 8 cases were identified. Seven single-institution studies contained adequate clinical follow-up information, and the rest had mainly focused on the pathologic features of the disease. Both the registry and the single-institution studies showed that patients with SCUB presented with a high histologic grade, advanced-stage disease, and a poor prognosis. Comparing the single-institution studies to the Surveillance, Epidemiology, and End Results cohorts, significant differences were found in the age at diagnosis, male-to-female ratio, tumor stage, treatment pattern (cystectomy, radiation, and chemotherapy), and outcomes, likely reflecting differences in referral and practice patterns. The tumor stage was identified as a significant predictor for cancer-specific survival. The results of the present study suggest that SCUB is not as rare as previously thought. Patients with SCUB should be referred to specialists or centers with extensive experience with this rare and serious disease.

Circulating and disseminated tumor cells from breast cancer patient-derived xenograft-bearing mice as a novel model to study metastasis

Introduction

Real-time monitoring of biologic changes in tumors may be possible by investigating the transitional cells such as circulating tumor cells (CTCs) and disseminated tumor cells in bone marrow (BM-DTCs). However, the small numbers of CTCs and the limited access to bone marrow aspirates in cancer patients pose major hurdles. The goal of this study was to determine whether breast cancer (BC) patient-derived xenograft (PDX) mice could provide a constant and renewable source of CTCs and BM-DTCs, thereby representing a unique system for the study of metastatic processes.

Methods

CTCs and BM-DTCs, isolated from BC PDX-bearing mice, were identified by immunostaining for human pan-cytokeratin and nuclear counterstaining of red blood cell-lysed blood and bone marrow fractions, respectively. The rate of lung metastases (LM) was previously reported in these lines. Associations between the presence of CTCs, BM-DTCs, and LM were assessed by the Fisher’s Exact and Cochran-Mantel-Haenszel tests. Two separate genetic signatures associated with the presence of CTC clusters and with lung metastatic potential were computed by using the expression arrays of primary tumors from different PDX lines and subsequently overlapped to identify common genes.

Results

In total, 18 BC PDX lines were evaluated. CTCs and BM-DTCs, present as either single cells or clusters, were detected in 83% (15 of 18) and 62.5% (10 to16) of the lines, respectively. A positive association was noted between the presence of CTCs and BM-DTCs within the same mice. LM was previously found in 9 of 18 (50%) lines, of which all nine had detectable CTCs. The presence of LM was strongly associated with the detection of CTC clusters but not with individual cells or detection of BM-DTCs. Overlapping of the two genetic signatures of the primary PDX tumors associated with the presence of CTC clusters and with lung metastatic potential identified four genes (HLA-DP1A, GJA1, PEG3, and XIST). This four-gene profile predicted distant metastases-free survival in publicly available datasets of early BC patients.

Conclusion

This study suggests that CTCs and BM-DTCs detected in BC PDX-bearing mice may represent a valuable and unique preclinical model for investigating the role of these rare cells in tumor metastases.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-014-0508-5) contains supplementary material, which is available to authorized users.

RNA-seq reveals aurora kinase-driven mTOR pathway activation in patients with sarcomatoid metastatic renal cell carcinoma

Sarcomatoid metastatic renal cell carcinoma (mRCC) is associated with a poor prognosis, and the biology of the disease has been inadequately characterized. RNA sequencing (RNA-seq) was performed on adjacent benign, clear cell, and sarcomatoid components from clinical specimens with sarcomatoid mRCC. M phase and cell-cycle pathways were enriched in sarcomatoid versus adjacent clear cell components, suggesting greater cell proliferation. The expression of aurora kinase A (AURKA) was increased as part of these pathways, and its increased expression was validated by quantitative PCR (qPCR). Immunohistochemical (IHC) analysis revealed that AURKA levels were increased in sarcomatoid tissue compared with their benign or clear cell parts. The increase in AURKA correlated with increased mTOR pathway activity, as evidenced by increased expression of phosphorylated mTOR (S2448) and ribosomal protein S6K (T389). When AURKA was stably expressed in a RCC cell line (Renca), it resulted in increased expression and activity of mTOR, suggesting that overexpression of AURKA can activate the mTOR pathway. These results warrant the analysis of a larger clinical cohort and suggest that targeting AURKA and/or mTOR in patients with sarcomatoid mRCC should be explored.

IMPLICATIONS

Comparative RNA-seq of adjacent sarcomatoid and clear cell histology of RCC indicates a proliferative phenotype and increased AURKA-dependent activation of mTOR signaling in sarcomatoid RCC, which could be targeted by available agents.

Sarcomatoid carcinoma represents a complete phenotype with various pathways of epithelial mesenchymal transition

AIMS

Sarcomatoid carcinoma (SC) is considered to be a result of the sarcomatoid change of epithelial carcinoma. However, epithelial-mesenchymal transition (EMT) in SC has been insufficiently studied.

METHODS

We evaluated the expression patterns of EMT-related phenotypic markers with transcription factors in 27 SCs originating from various organs, and we investigated the phenotypic characteristics of SCs classified as complete, incomplete or wild-type. We further analysed correlations between EMT-related phenotype markers and transcription factors.

RESULTS

Epithelial markers (E-cadherin, claudin-3 and claudin-4) were consistently down-regulated, whereas mesenchymal markers (S100A4, α-smooth muscle actin (SMA), vimentin, PDGFRα and β-catenin) were variously expressed except for vimentin. EMT-related transcription factors (SIP1, Snail1, Slug, Twist1, ZEP1 and Oct-4) also showed various expression patterns. The expression patterns of phenotypic markers showed that most SCs (22/27, 81.5%, 95% CI 65.8 to 97.1%) had complete EMT phenotypes, whereas the remaining 5 (18.5%, 95% CI 2.8 to 24.1%) were of incomplete type. Unsupervised hierarchical clustering analysis revealed that SCs were clustered into several subgroups by EMT-related protein expression pattern. Twist1 positivity was significantly concordant with α-SMA positivity (κ value: 0.908; 95% CI 0.73 to 1.00, p<0.001, adjusted p<0.001). The EMT phenotypes of SC were simple, with complete phenotype being the predominant form, and the morphological changes of the SCs were also relevant in terms of EMT.

CONCLUSIONS

SC seems to be an irreversible, permanent change in the EMT phenomenon, with complete EMT phenotypes and various EMT-related pathways being involved in SC.

Epithelial-to-mesenchymal(-like) transition as a relevant molecular event in malignant gliomas

Tumor dissemination and metastatic behavior account for the vast majority of cancer associated mortality. Epithelial tumors achieve this progressive state via epithelial-to-mesenchymal transition (EMT); however, the importance of this process in the neuroepithelial context is currently very controversially discussed. The review describes the current research status concerning EMT-like changes in malignant gliomas including the role of TWIST1, ZEB1/ZEB2 and SNAIl1/SNAIl2 as inducers for cell-invasiveness in GBMs. Furthermore, WNT/β-catenin signaling with its key-component FRIZZLED4 activating an EMT-like program in malignant gliomas and its relationship to the stem-like phenotype as well as discoveries on micro-RNA-level regulating the EMT-like process are discussed.

Nuclear p63 expression in osteoblastic tumors

Expression of the p63 tumor suppressor protein has been reported in the mononuclear stromal cells of giant cell tumor of the bone, which may represent osteoblast-precursor cells. Only a limited number of osteoblastic tumors have been studied for p63 expression thus far. We therefore examined whether p63 may serve as a marker for osteoblastic differentiation in osteosarcomas or as a differential diagnostic marker to distinguish osteoblastoma from osteosarcoma. Immunohistochemical stains for p63 were performed on a tissue microarray containing 71 chemotherapy naïve biopsy samples of osteosarcoma, 21 whole sections of osteosarcoma, and 8 osteoblastomas. Nuclear p63 was detected in seven of eight osteoblastomas but was restricted to stromal cells within primitive, immature-appearing areas of osteoid deposition. Although only 7 of 71 (10 %) biopsy samples of osteosarcoma represented on the tissue microarray were positive for p63, 7 of 21 (33 %) osteosarcomas were positive when whole tissue sections were evaluated. Although p63 is detected in most osteoblastomas, it is also observed in a significant subset of osteosarcomas, severely limiting its utility in distinguishing between benign and malignant osteoblastic tumors. The relatively low prevalence of p63 expression in osteosarcoma would also seem to preclude its use as a marker of osteoblastic differentiation in skeletal sarcomas.

Myeloma as a model for the process of metastasis: implications for therapy

Multiple myeloma (MM) is a plasma cell dyscrasia characterized by the presence of multiple myelomatous "omas" throughout the skeleton, indicating that there is continuous trafficking of tumor cells to multiple areas in the bone marrow niches. MM may therefore represent one of the best models to study cell trafficking or cell metastasis. The process of cell metastasis is described as a multistep process, the invasion-metastasis cascade. This involves cell invasion, intravasation into nearby blood vessels, passage into the circulation, followed by homing into predetermined distant tissues, the formation of new foci of micrometastases, and finally the growth of micrometastasis into macroscopic tumors. This review discusses the significant advances that have been discovered in the complex process of invasion-metastasis in epithelial carcinomas and cell trafficking in hematopoietic stem cells and how this process relates to progression in MM. This progression is mediated by clonal intrinsic factors that mediate tumor invasiveness as well as factors present in the tumor microenvironment that are permissive to oncogenic proliferation. Therapeutic agents that target the different steps of cell dissemination and progression are discussed. Despite the significant advances in the treatment of MM, better therapeutic agents that target this metastatic cascade are urgently needed.

Epithelial-mesenchymal transition in malignant mesothelioma

Epithelial-mesenchymal transition is a physiopathological process by which epithelial cells acquire mesenchymal shape and properties. Malignant mesothelioma is histologically characterized by the concomitant presence of epithelioid and sarcomatoid features, the latter being associated to worse prognosis, thus suggesting a role of epithelial-mesenchymal transition in this dual phenotype. We studied 109 malignant mesotheliomas (58 epithelioid, 26 sarcomatoid, and 25 biphasic) by immunohistochemistry and qRT-PCR analysis, and demonstrated a substantial switch from epithelial markers (E-cadherin, β-catenin, and cytokeratins 5/6) to mesenchymal markers (N-cadherin, vimentin, α-smooth muscle actin, Snail, Slug, Twist, ZEB1, ZEB2, S100A4, MMP2, and MMP9) through epithelioid to biphasic and sarcomatoid histotypes. In agreement with these findings, the ectopic expression of miR-205 (a repressor of ZEB1 and ZEB2 expression) in MeT-5A (mesothelial cell line), H2452 (an epithelioid malignant mesothelioma cell line) and MSTO-211H (a biphasic malignant mesothelioma cell line) not only induced a significant reduction of ZEB1 and ZEB2 and a consequent up-regulation of E-cadherin gene expression, but also inhibited migration and invasion. Moreover, miR-205 was significantly down-regulated in biphasic and sarcomatoid histotypes (qRT-PCR and in situ hybridization analyses). Collectively, our findings indicate that epithelial-mesenchymal transition has a significant part in the morphological features of malignant mesothelioma. In particular, miR-205 down-regulation correlated significantly with both a mesenchymal phenotype and a more aggressive behavior.

Sarcomatoid conversion of clear cell renal cell carcinoma in relation to epithelial-to-mesenchymal transition

Approximately 8% of clear cell renal cell carcinoma cases contain regions of radically different morphology, demonstrating a mesenchymal appearance histologically resembling sarcomas. These biphasic neoplasms are called sarcomatoid clear cell renal cell carcinoma. Patients diagnosed with sarcomatoid clear cell renal cell carcinoma face a considerably worse prognosis due to an increased propensity for metastasis. In the present study we investigate whether the sarcomatoid conversion of clear cell renal cell carcinoma could be interpreted as linked to the process of epithelial-mesenchymal transition. Using 6 biphasic clear cell renal cell carcinoma cases we show that sarcomatoid clear cell renal cell carcinoma shares characteristic markers associated with loss of von Hippel-Lindau tumor suppressor with conventional clear cell renal cell carcinoma and also exhibits a markedly higher proliferative index. Furthermore the sarcomatoid elements demonstrate an enhanced expression of epithelial-mesenchymal transition related mesenchymal markers as compared with the clear cell renal cell carcinoma counterparts. We further selected a representative case, clinically demonstrating direct overgrowth of the sarcomatoid component into the liver and colon, for extended immunohistochemical characterization, resulting in a further set of positive and negative epithelial-mesenchymal transition markers as well as pronounced transforming growth factor β positivity, indicating that sarcomatoid clear cell renal cell carcinoma may be associated to epithelial-mesenchymal transition. Transforming growth factor β1 exposure of in vitro cultured primary clear cell renal cell carcinoma cells resulted in cells adopting a mesenchymal morphology similar to sarcomatoid clear cell renal cell carcinoma. Corresponding changes in RNA levels for key epithelial-mesenchymal transition markers were also seen. We therefore suggest that sarcomatoid clear cell renal cell carcinoma morphologically and immunohistochemically may represent a completed epithelial-mesenchymal transition and that transforming growth factor β1 could be an important driving force during the sarcomatoid transdifferentiation of clear cell renal cell carcinoma.

p63 is a suppressor of tumorigenesis and metastasis interacting with mutant p53

p53 mutations, occurring in two-thirds of all human cancers, confer a gain of function phenotype, including the ability to form metastasis, the determining feature in the prognosis of most human cancer. This effect seems mediated at least partially by its ability to physically interact with p63, thus affecting a cell invasion pathway, and accordingly, p63 is deregulated in human cancers. In addition, p63, as an 'epithelial organizer', directly impinges on epidermal mesenchimal transition, stemness, senescence, cell death and cell cycle arrest, all determinant in cancer, and thus p63 affects chemosensitivity and chemoresistance. This demonstrates an important role for p63 in cancer development and its progression, and the aim of this review is to set this new evidence that links p63 to metastasis within the context of the long conserved other functions of p63.

TWISTing an embryonic transcription factor into an oncoprotein

Over the past decade, the reactivation of TWIST embryonic transcription factors has been described as a frequent event and a marker of poor prognosis in an impressive array of human cancers. Growing evidence now supports the premise that these cancers hijack TWIST's embryonic functions, granting oncogenic and metastatic properties. In this review, we report on the history and recent breakthroughs in understanding TWIST protein functions and the emerging role of the associated epithelial-mesenchymal transition (EMT) in tumorigenesis. We then broaden the discussion to address the general contribution of reactivating embryonic programs in cancerogenesis.

Clinicopathological and immunohistochemical features of oral spindle cell carcinoma

BACKGROUND

Oral spindle cell carcinoma (SpCC) is a rare variant of oral squamous cell carcinoma (SCC). The aims of this study were to compare the clinicopathologic and immunohistochemical features of oral SpCC with conventional oral SCC.

METHODS

Five cases of oral SpCC and 10 cases of oral SCC (five well-differentiated and five poorly differentiated) were evaluated through conventional hematoxylin and eosin staining and immunohistochemical reactions to cytokeratins (CK), vimentin, desmin, smooth muscle actin, muscle-specific actin, S-100 protein, epithelial membrane antigen (EMA), p53, and ki-67.

RESULTS

Oral SpCC showed predilection for males on their sixth decade of life, presenting clinically as painful infiltrative ulcers or ulcerated exophytic polypoid masses, preferably located on the alveolar mucosa. Mesenchymal markers were expressed in the spindle cell but not in the carcinomatous component of SpCC, and it was negative in all SCC. CKs AE1/AE3, 6, 14, and EMA were positive on both carcinomatous and spindle cell components of most SpCCs. These tumors also presented higher p53 and ki-67 expression and no CK 1 expression in contrast to well-differentiated SCC.

CONCLUSION

Oral SpCC presented a different clinical profile than conventional SCC and histopathologic features and p53 and ki-67 expression closer to poorly differentiated SCC. Besides mesenchymal markers, CK AE1/AE3, 6, 14, and EMA expression on spindle cells may be useful as an adjunct on microscopical differential diagnosis of SpCC.

Use of Myoepithelial Cell Markers in the Differential Diagnosis of Benign, In situ, and Invasive Lesions of the Breast

Immunohistochemical markers for myoepithelial cells are commonly used to distinguish invasive from noninvasive lesions in the breast. The approach takes advantage of the fact that conventional invasive carcinomas lack surrounding myoepithelial cells, whereas nearly all benign lesions and in situ carcinomas retain their myoepithelial cell layer. Although conceptually straightforward, the interpretation of myoepithelial cell markers can be complicated by misleading patterns of reactivity (such as stromal or tumor cell staining) or lack of reactivity (due to reduced numbers of myoepithelial cells or variable antigenicity). In this article, we discuss the advantages and disadvantages of commonly used myoepithelial cell markers, their general utility in distinguishing invasive from noninvasive processes, and pitfalls in their interpretation. We also examine whether the detection of myoepithelial cells is helpful in the evaluation of papillary lesions, another common application. Myoepithelial cell markers can be diagnostically useful in the distinction of many benign, in situ, and invasive lesions, but they must be interpreted in conjunction with careful morphologic analysis.

Utility of p63 in the differential diagnosis of atypical fibroxanthoma and spindle cell squamous cell carcinoma

Atypical fibroxanthoma (AFX), spindle cell squamous cell carcinoma (SCSCC) and spindle cell melanoma are the primary entities in the differential diagnosis of a cytologically atypical spindle cell tumor arising on sun-damaged skin. AFX is generally regarded as a diagnosis of exclusion in this context: in the absence of S100 or keratin reactivity, a diagnosis of AFX is favored. However, keratin reactivity may be focal or even absent in SCSCC, and although numerous positive markers of AFX have been proposed, none has shown sufficient sensitivity and specificity for routine diagnostic use. We evaluated 20 AFX and 10 SCSCC with a panel of cytokeratins and p63 to assess the utility of the latter antibody in this differential diagnosis. All 10 SCSCC showed strong expression of p63, whereas all 20 AFX were p63 negative. Two additional cases (excluded from the study) were negative for keratins and S100 on initial shave biopsies, resulting in a favored diagnosis of AFX, but p63 stains performed retrospectively were positive. However, review of the excision specimens in both cases revealed deep subcutaneous extension, excluding AFX. p63 reactivity argues against the diagnosis of AFX and is therefore a useful addition to the standard immunohistochemical panel for cutaneous spindle cell neoplasms.

Epithelial-mesenchymal transition markers in pancreatic ductal adenocarcinoma

OBJECTIVES

Expression of transcription factors that mediate epithelial-mesenchymal transition (EMT), such as Twist and Slug, is correlated with poor prognosis in many tumor types. Selected EMT markers were studied in a series of pancreatic ductal adenocarcinomas (PDAs) and benign pancreatic tissues to determine whether expression levels correlated with diagnosis, histologic grade, or patient outcome.

METHODS

Immunohistochemical stains for Twist, Slug, and N-cadherin were performed using a tissue microarray containing 68 PDAs and 38 samples of normal pancreas or chronic pancreatitis tissues.

RESULTS

Twist and Slug were identified in both the nucleus and cytoplasm of benign pancreatic ductal epithelium, chronic pancreatitis, and PDA. Compared with normal ductal epithelium, nuclear levels of Twist are decreased in PDA. None of the other EMT markers showed significant differences in staining indices among the diagnostic groups. There were no correlations between EMT marker expression and histologic grade. Epithelial-mesenchymal transition marker expression was not associated with N-cadherin expression, patient outcome, or duration of survival.

CONCLUSIONS

Decreased expression of nuclear Twist is observed in malignant pancreatic epithelium. However, use of Twist as a diagnostic marker is precluded because decreased expression is also seen in chronic pancreatitis. None of the markers studied were predictive of patient outcome.