Diagnostic Utility of Novel Stem Cell Markers SALL4, OCT4, NANOG, SOX2, UTF1, and TCL1 in Primary Mediastinal Germ Cell Tumors

Higher expression of SALL4-A isoform is correlated with worse outcomes and progression of the disease in subtype of testicular germ cell tumours

BACKGROUND

The transcription factor SALL4 is associated with embryonic pluripotency and has proposed as a novel immunohistochemistry (IHC) marker for diagnosing germ cell tumours. SALL4 comprises three isoforms, and SALL4-A being the full-length isoform. Studying its isoforms could revolutionize testicular cancer prognosis and subtype differentiation.

METHODS

The expression and clinical significance of isoform 'A' of SALL4 was evaluated in 124 testicular germ cell tumours (TGCTs) subtypes, adjacent 67 normal tissues and 22 benign tumours, using immunohistochemistry on tissue microarrays (TMA).

RESULTS

A statistically significant higher expression of nuclear and cytoplasmic SALL4-A was detected in TGCTs histological subtypes and benign tumours compared to the normal tissues. Seminoma and yolk sac tumours had the highest nuclear and cytoplasmic expression of SALL4-A. A significant correlation was detected between the higher nuclear expression of SALL4-A and increased pT stages (P = 0.026) in seminomas. Whereas in embryonal carcinomas, cytoplasmic expression of SALL4-A was associated with the tumour recurrence (P = 0.04) and invasion of the epididymis (P = 0.011).

CONCLUSIONS

SALL4-A isoform expression in the cytoplasm and nucleus of TGCTs may be associated with histological differentiation. In the seminoma subtype of TGCTs, higher expression of SALL4-A may be used as a predictive indicator of poorer outcomes and prognosis.

Non-gestational choriocarcinoma: unraveling the similarities and distinctions from its gestational counterpart

Choriocarcinoma is a highly vascular and invasive tumor of anaplastic trophoblast, predominantly made up of cytotrophoblasts and syncytiotrophoblasts without villi. Based on its origin, choriocarcinoma can be either gestational or non-gestational. Non-gestational choriocarcinoma can be of germ cell origin, or can be seen in association with a somatic high-grade malignancy. It is difficult to differentiate gestational from non-gestational choriocarcinoma, especially in the reproductive age group. It is important to distinguish between the two, for accurate staging and prognostication, deciding the primary treatment modality, (ie, surgery or chemotherapy), and tailoring follow-up timeframes after diagnosis. An extensive literature search was performed regarding all cases of non-gestational choriocarcinoma, published before March 2023. A note was made of whether the origin of choriocarcinoma was ascertained and how gestational choriocarcinoma was differentiated from non-gestational choriocarcinoma. The keywords used for literature search were "non-gestational choriocarcinoma", "primary choriocarcinoma", "ovarian choriocarcinoma", "ovarian germ cell tumors", or "choriocarcinomatous differentiation". This review aims to summarize the similarities and differences in the epidemiology, pathogenesis, clinical presentation, and management guidelines between gestational and non-gestational choriocarcinoma, which can form an important educational resource for clinicians and laboratory physicians dealing with such cases.

Primary mediastinal seminoma with azoospermia: case report and review of the literature

Introduction

Since the first report, primary mediastinal seminoma has a low incidence in the population, and it mainly affects young and middle-aged men, is clinically rare, and accounts for a very small proportion of mediastinal tumors. In this study, we describe the first case of primary mediastinal seminoma with azoospermia and hypothesize that the coexistence of the two disorders may not be a coincidence.

Case report

A 16-year-old man presented with chest tightness and chest pain, a mediastinal mass on chest CT, and abnormal 18F-fluoro-deoxyglucose uptake on a PET-CT scan. By biopsy of the mass, the pathological diagnosis was a primary mediastinal seminoma. Because chemotherapy is included in the treatment of the tumor, the patient underwent sperm freezing before treatment, considering that chemotherapy can affect fertility, but the patient was diagnosed with azoospermia. Finally, the patient underwent tumor resection and postoperative chemotherapy. No tumor recurrence was observed at the current follow-up.

Conclusion

Primary mediastinal seminoma is mainly confirmed by histopathological examination, and surgery and chemoradiotherapy are the current treatments. In patients with mediastinal seminoma or azoospermia, doctors should be aware that the two disorders may coexist, especially in men who have fertility requirements or long-term infertility, and that examination of the mediastinum and semen may lead to unexpected findings in the diagnosis and treatment. For mediastinal germ cell tumors, genetic testing is of great value in the treatment of tumors and the prediction of associated diseases. Future studies exploring the potential correlation between mediastinal seminoma and azoospermia will be prospective.

New insights on testicular cancer prevalence with novel diagnostic biomarkers and therapeutic approaches

BACKGROUND

Testicular cancer (TC), comprising merely 1% of male neoplasms, holds the distinction of being the most commonly encountered neoplasm among young males.

RECENT FINDINGS

Most cases of testicular neoplasms can be classified into two main groups, namely germ cell tumors representing approximately 95% of the cases, and sex cord-stromal tumors accounting for about 5% of the cases. Moreover, its prevalence is on the rise across the globe. TC is a neoplastic condition characterized by a favorable prognosis. The advent of cisplatin-based chemotherapeutic agents in the latter part of the 1970s has led to a significant enhancement in the 5-year survival rate, which presently surpasses 95%. Given that TC is commonly detected before reaching the age of 40, it can be anticipated that these individuals will enjoy an additional 40-50 years of life following successful treatment. The potential causes of TC are multifactorial and related to different pathologies. Accurate identification is imperative to guarantee the utmost efficacious and suitable therapy. To a certain degree, this can be accomplished through the utilization of blood examinations for neoplastic indicators; nonetheless, an unequivocal diagnosis necessitates an evaluation of the histological composition of a specimen via a pathologist.

CONCLUSION

TC is multifactorial and has various pathologies, therefore this review aimed to revise the prenatal and postnatal causes as well as novel diagnostic biomarkers and the therapeutic strategies of TC.

Primary germ cell tumours of the mediastinum: A review with emphasis on diagnostic challenges

This article will review current aspects of the histopathological, immunohistochemical and molecular analysis of primary mediastinal germ cell tumours (PMGCTs) as well as their aetiological, epidemiological, clinical and therapeutic features. PMGCTs represent an important differential diagnosis in the spectrum of mediastinal tumours, and their diagnosis is usually made on small tissue samples from core needle biopsies in combination with diagnostic imaging and serum tumour markers. As in lymphomas, a small biopsy is often the only viable tumour sample available from these patients, as they receive chemotherapy prior to eventual surgical resection. Pathologists therefore need to apply an efficient combination of immunohistochemical markers to confirm the diagnosis of a PMGCT and to exclude morphological mimics.

Clinical Significance of Overexpression of Oct4 in Advanced Stage Gallbladder Carcinoma

BACKGROUND

Oct4 has critical role in maintaining pluripotency, proliferative potential, and self-renewal capacity in embryonic stem and germ cells. Although Oct4 has been shown to be upregulated in many cancers, its clinical significance in gallbladder carcinoma is poorly understood.

METHODS

We studied the expression profile of Oct4 in 61 GBC and 30 chronic cholecystitis (as control) using real time RT-PCR, western blotting, and immunohistochemistry. The expression data was correlated with clinico-pathological parameters. The diagnostic utility was assessed through ROC curve, and prognostic value was analyzed by Kaplan-Meier method.

RESULTS

Oct4 was significantly upregulated at mRNA as well as protein levels. The higher mRNA expression shows significant association with late stage, late T stage, and higher grade of tumor. A significant positive correlation was also observed with stage, T stage, and tumor grade. Sum score analysis of protein expression shows positive correlation with stage and the presence or absence of gallstone in tumor samples. The ROC curve analysis revealed the moderate diagnostic potential of Oct4. Kaplan-Meier analysis showed that patients having higher expression of Oct4 were having low mean survival compared with the patients with lower Oct4 expression.

CONCLUSION

In conclusion, our data suggests that higher expression of Oct4 may serve as potential biological indicator for tumor aggressiveness and poor prognosis of GBC.

miR-203 drives breast cancer cell differentiation

A hallmark of many malignant tumors is dedifferentiated (immature) cells bearing slight or no resemblance to the normal cells from which the cancer originated. Tumor dedifferentiated cells exhibit a higher capacity to survive to chemo and radiotherapies and have the ability to incite tumor relapse. Inducing cancer cell differentiation would abolish their self-renewal and invasive capacity and could be combined with the current standard of care, especially in poorly differentiated and aggressive tumors (with worst prognosis). However, differentiation therapy is still in its early stages and the intrinsic complexity of solid tumor heterogeneity demands innovative approaches in order to be efficiently translated into the clinic. We demonstrate here that microRNA 203, a potent driver of differentiation in pluripotent stem cells (ESCs and iPSCs), promotes the differentiation of mammary gland tumor cells. Combining mouse in vivo approaches and both mouse and human-derived tridimensional organoid cultures, we report that miR-203 influences the self-renewal capacity, plasticity and differentiation potential of breast cancer cells and prevents tumor cell growth in vivo. Our work sheds light on differentiation-based antitumor therapies and offers miR-203 as a promising tool for directly confronting the tumor-maintaining and regeneration capability of cancer cells.

Testicular Germ Cell Tumor Tissue Biomarker Analysis: A Comparison of Human Protein Atlas and Individual Testicular Germ Cell Tumor Component Immunohistochemistry

The accurate management of testicular germ cell tumors (TGCTs) depends on identifying the individual histological tumor components. Currently available data on protein expression in TGCTs are limited. The human protein atlas (HPA) is a comprehensive resource presenting the expression and localization of proteins across tissue types and diseases. In this study, we have compared the data from the HPA with our in-house immunohistochemistry on core TGCT diagnostic genes to test reliability and potential biomarker genes. We have compared the protein expression of 15 genes in TGCT patients and non-neoplastic testicles with the data from the HPA. Protein expression was converted into diagnostic positivity. Our study discovered discrepancies in three of the six core TGCT diagnostic genes, POU5F1, KIT and SOX17 in HPA. DPPA3, CALCA and TDGF1 were presented as potential novel TGCT biomarkers. MGMT was confirmed while RASSF1 and PRSS21 were identified as biomarkers of healthy testicular tissue. Finally, SALL4, SOX17, RASSF1 and PRSS21 dysregulation in the surrounding testicular tissue with complete preserved spermatogenesis of TGCT patients was detected, a potential early sign of neoplastic transformation. We highlight the importance of a multidisciplinary collaborative approach to fully understand the protein landscape of human testis and its pathologies.

An update on diagnostic tissue-based biomarkers in testicular tumors

Testicular cancer is rare overall but comprises the most common solid malignancy diagnosed in young men aged ∼20-40 years. Most testicular neoplasms generally fall into 2 broad categories: germ cell tumors (GCTs; ∼95%) and sex cord-stromal tumors (SCSTs ∼5%). Given the relative rarity of these tumors, diagnostic biomarkers are highly relevant for their diagnosis. Over the past several decades, diagnostic biomarkers have improved dramatically through targeted immunohistochemical and molecular characterization. Despite these recent advances, most markers are not perfectly sensitive or entirely specific. Therefore, they need to be used in combination and interpreted in context. In this review, we summarize tissue-based biomarkers relevant to the pathologist, with a focus on practical diagnostic issues that relate to testicular GCT and SCST.

Primary mediastinal germ cell tumors

Mediastinal germ cell tumors share similar histopathological, immunohistochemical, and molecular features with their counterparts in the gonads. Therefore, proper clinical and radiological evaluation of patients with an anterior mediastinal mass becomes essential in the final interpretation of these tumors. The gold standard for the diagnosis of these tumors remains histopathological evaluation. However, immunohistochemical stains and molecular studies also provide an aid in cases in which the histology is not typical. It is also important to keep in mind that a small mediastinoscopic biopsy may not be representative of the entire neoplasm. In this review, we will provide our perspective regarding histopathological diagnosis, staging, immunohistochemical and molecular profile, and briefly family of tumors address pertinent epidemiological, clinical and treatment options. However, the main emphasis is to review the process of pathological assessment in pre and post-treated tumors. Knowledge of the different growth patterns and histological associations is important, mainly when confronted with mediastinoscopic biopsies, which ultimately will determine treatment options.

Immune-related mechanisms and immunotherapy in extragonadal germ cell tumors

Purpose of review

Extragonadal germ cell tumors (EGCTs) are relatively rare tumors, accounting for 1%-5% of all GCTs. In this review, we summarize the current research progress regarding the pathogenesis, diagnosis, and treatment of EGCTs from an immunology perspective.

Recent findings

The histological origin of EGCTs is related to a gonadal origin, but they are located outside the gonad. They show great variation in morphology and can occur in the cranium, mediastinum, sacrococcygeal bone, and other areas. The pathogenesis of EGCTs is poorly understood, and their differential diagnosis is extensive and challenging. EGCT behavior varies greatly according to patient age, histological subtype, and clinical stage.

Summary

This review provides ideas for the future application of immunology in the fight against such diseases, which is a hot topic currently.

Selective elimination of pluripotent stem cells by PIKfyve specific inhibitors

Inhibition of PIKfyve phosphoinositide kinase selectively kills autophagy-dependent cancer cells by disrupting lysosome homeostasis. Here, we show that PIKfyve inhibitors can also selectively eliminate pluripotent embryonal carcinoma cells (ECCs), embryonic stem cells, and induced pluripotent stem cells under conditions where differentiated cells remain viable. PIKfyve inhibitors prevented lysosome fission, induced autophagosome accumulation, and reduced cell proliferation in both pluripotent and differentiated cells, but they induced death only in pluripotent cells. The ability of PIKfyve inhibitors to distinguish between pluripotent and differentiated cells was confirmed with xenografts derived from ECCs. Pretreatment of ECCs with the PIKfyve specific inhibitor WX8 suppressed their ability to form teratocarcinomas in mice, and intraperitoneal injections of WX8 into mice harboring teratocarcinoma xenografts selectively eliminated pluripotent cells. Differentiated cells continued to proliferate, but at a reduced rate. These results provide a proof of principle that PIKfyve specific inhibitors can selectively eliminate pluripotent stem cells in vivo as well as in vitro.

Urachal yolk sac tumor penetrating the bladder as a diagnostic challenge: a case report and review of the literature

Background

Yolk sac tumor (YST) is a germ cell tumor. It is primarily located in the gonads but can also occur extragonadally (extragonadal yolk sac tumor - EGYST), most commonly in the pelvis, retroperitoneum or mediastinum. Only a few YSTs of the urachus have been described.

Case report

We present a rare case report of a 37-year-old male with episodes of macroscopic hematuria. The histological specimen obtained by transurethral resection showed a solid, and in some parts papillary infiltrative, high-grade tumor with numerous areas of marked nuclear atypia and clear invasion between the detrusor bundles. Glandular pattern has been observed in only minority of the tumor. Immunohistochemistry showed significant positivity for GPC3, SALL4 and cytokeratins AE1/AE3, while KRT7 and GATA3 were negative. We concluded that the biopsy findings were consistent with urothelial carcinoma with infrequent YST differentiation. In definitive surgical specimens we found a malignant epithelial, glandular and cystically arranged tumor of germinal appearance arising from urachus. The surrounding urothelium was free of invasive or in situ tumor changes. We reclassified the tumor as a urachal YST.

Conclusion

EGYST was suspected because glandular and hepatoid structures were found, but the presence of these structures should be verified by immunohistochemistry.

Role of SALL4 and Nodal in the prognosis and tamoxifen resistance of estrogen receptor-positive breast cancer

Despite the discovery of a number of different mechanisms underlying tamoxifen resistance, its molecular pathway is not completely clear. The upregulation of SALL4 and Nodal has been reported in breast cancer. Nevertheless, their role in tamoxifen resistance has not been investigated. In the present study, we compared Nodal and SALL4 expression in 72 tamoxifen sensitive (TAMS) and tamoxifen-resistant (TAMR) patients. Afterward, the correlation of expression data with clinicopathological features and survival of patients was studied. Results showed that both SALL4 and Nodal were significantly upregulated in TAMR compared to TAMS patients. Besides, there was a positive association between Nodal and SALL4 expression. Furthermore, we evaluated their correlation with the expression of Oct4, Nanog and Sox2 stemness markers. The results demonstrated that in most tissue samples there was a positive correlation between Nodal and SALL4 expression with these stemness markers. Besides, the overexpression of SALL4 and Nodal significantly correlated with the N stage. Moreover, the overexpression of SALL4 was associated with extracapsular invasion and lymphatic invasion. High level expressions of SALL4 and Nodal had a significant association with worse disease-free survival (DFS) rates. In addition, increased level of Nodal expression provides a superior predictor factor for DFS. The multivariate Cox regression analysis also revealed that for DFS, perineural invasion (PNI) was independently an unfavorable prognostic value. These findings suggest that the high expression of SALL4 and Nodal could contribute to tamoxifen resistance and worse survival rates in tamoxifen-treated ER⁺ breast cancer patients.

Mediastinal Germ Cell Tumors: A Review and Update on Pathologic, Clinical, and Molecular Features

Mediastinal germ cell tumors (MGCTs) are the most common extragonadal germ cell tumors (GCTs) and most often arise in the anterior mediastinum with a male predilection. MGCTs also have a predilection for patients with Klinefelter syndrome and possibly other genetic conditions. MGCTs, as GCTs at other extragonadal sites, are thought to arise from germ cells improperly retained during migration along the midline during embryogenesis. Similar to their counterparts in the testes, MGCTs are classified into seminomatous and nonseminomatous GCTs. Seminomatous MGCT represents pure seminoma, whereas nonseminomatous MGCTs encompass pure yolk sac tumors, embryonal carcinoma, choriocarcinoma, mature or immature teratoma, and mixed GCTs with any combination of GCT types, including seminoma. Somatic-type or hematologic malignancies can also occur in association with a primary MGCT. MGCTs share molecular findings with GCTs at other sites, most commonly the presence of chromosome 12p gains and isochromosome i(12p). Treatment includes neoadjuvant chemotherapy followed by surgical resection of residual tumor, with the exception of benign teratomas, which require only surgical resection without chemotherapy. In this review, we highlight and provide an update on pathologic, clinical, and molecular features of MGCTs. Immunohistochemical profiles of each tumor type, as well as differential diagnostic considerations, are discussed.

Pattern of placental alkaline phosphatase (PLAP) expression in human tumors: a tissue microarray study on 12,381 tumors

Placental alkaline phosphatase (PLAP) is commonly expressed at high levels in testicular germ cell tumors. PLAP immunohistochemistry (IHC) is thus often used to confirm this diagnosis, especially in cases of putative metastasis. However, other tumors can also express PLAP. To comprehensively determine PLAP expression in normal and tumor tissue, a tissue microarray containing 16,166 samples from 131 different tumor types and subtypes as well as 608 samples from 76 different normal tissue types was analyzed by IHC. Moderate to strong PLAP positivity was found in 27 (21%) of 131 different tumor types including seminoma (96%), embryonal carcinoma (85%), and yolk sac tumors of the testis (56%); endometrioid carcinoma of the endometrium (28%) and the ovary (20%); gastric adenocarcinoma (22%); serous carcinoma (not otherwise specified) of the ovary (17%) and the uterus (11%); adenocarcinoma of the ampulla of Vater (15%); carcinosarcoma of the ovary (11%) and the uterus (8%); esophageal adenocarcinoma (10%); invasive urothelial carcinoma (4%); cholangiocarcinoma (2%); and adenocarcinoma of the lung (1%). Low‐level PLAP immunostaining, often involving only a small fraction of tumor cells, was seen in 21 additional tumor entities. The clinical significance of PLAP expression may vary between tumor types as high PLAP expression was linked to advanced pathological tumor stage (p = 0.0086), nodal metastasis (p = 0.0085), and lymphatic (p = 0.0007) and blood vessel invasion (p = 0.0222) in colorectal cancer, but to low pathological tumor stage in endometrial cancer (p = 0.0043). In conclusion, our data identify several tumor entities that can show PLAP expression at comparable levels to testicular germ cell tumors. These tumor entities need to be considered in cases of PLAP‐positive metastasis. Low‐level PLAP expression can be found in various other tumor entities and should generally not be viewed as a strong argument for germ cell neoplasia.

Multilocular thymic cyst (MTC) and other tumors with MTC features: Pitfalls in diagnosis

Cystic lesions of the anterior mediastinum represent a well-known group of benign lesions that are relatively common in the general practice, namely in the pediatric age group. In the adult population, multilocular thymic cyst (MTC) plays an important role in occurrence as it presents as a cystic anterior mediastinal mass that clinically may mimic another anterior mediastinal tumor. In general, MTC is of rather unusual occurrence and its histopathological features have been well described in the literature. However, similar histopathological features may also be associated with a gamut of other tumoral conditions that although unrelated may be encountered growing along the walls of these cystic structures. Herein a presentation of the classical MTC and the classical histopathological features of such entity in association with other tumoral conditions will be discussed. It is highly important to underscore that the final interpretation of some of these tumors is based on a thorough evaluation of the cystic lesion and a reasonable sampling for histological evaluation so that the proper interpretation can be reached. Needless to say, the radiological and clinical information of the patients with cystic anterior mediastinal lesions is very important in the final analysis of these cases.

Phase II trial of brentuximab vedotin in relapsed/refractory germ cell tumors

Background CD-30 is highly expressed in some patients with non-seminomatous germ-cell tumors. Brentuximab vedotin is an antibody-drug conjugate directed to CD-30. We report a phase 2 trial of brentuximab vedotin in patients with chemo-refractory GCT. Patients and methods This is a single arm, two cohort phase 2 trial investigating brentuximab vedotin 1.8 mg/kg IV every 3 weeks until disease progression or intolerable toxicities in patients with relapsed GCT who have no curative options. Patients with mGCT who progressed after first line cisplatin-based chemotherapy and after at least 1 salvage regimen (high-dose or standard-dose chemotherapy) were eligible. CD30 expression was assessed and two cohorts defined: CD30 positive and CD30 negative/unknown. Results 18 patients were enrolled. Median age 34.7 (range, 23-56). All patients had non-seminoma. Median AFP 4.9 (range, 1-219,345) and hCG 282 (range, 0.6-172,064). Five patients had late relapse (> 2 years). Median number of previous chemotherapy regimens was 3 (range, 2-7). Ten patients received prior high-dose chemotherapy. Seven patients had positive CD30 staining. There were two grade 3 treatment-related adverse events. No partial or complete responses were observed. 6 patients achieved radiographic stable disease (range, 9-14.9 weeks), 5 had elevated AFP or hCG at trial entry and all 5 had transient > 50% decline in baseline AFP/hCG: 4 had CD30 -ve and 2 had CD30 + ve staining; 10 patients had progression of disease as their best response; 2 were not evaluable for response. Conclusion Brentuximab vedotin does not appear to have clinically meaningful single-agent activity in patients with refractory GCT.

An Insight into the Role of UTF1 in Development, Stem Cells, and Cancer

The curiosity to understand the mechanisms regulating transcription in pluripotent cells resulted in identifying a unique transcription factor named Undifferentiated embryonic cell transcription factor 1 (UTF1). This proline-rich, nuclear protein is highly conserved among placental mammals with prominent expression observed in pluripotent, germ, and cancer cells. In pluripotent and germ cells, its role has been implicated primarily in proper cell differentiation, whereas in cancer, it shows tissue-specific function, either as an oncogene or a tumor suppressor gene. Furthermore, UTF1 is crucial for germ cell development, spermatogenesis, and maintaining male fertility in mice. In addition, recent studies have demonstrated the importance of UTF1 in the generation of high quality induced Pluripotent Stem Cells (iPSCs) and as an excellent biomarker to identify bona fide iPSCs. Functionally, UTF1 aids in establishing a favorable chromatin state in embryonic stem cells, reducing "transcriptional noise" and possibly functions similarly in re-establishing this state in differentiated cells upon their reprogramming to generate mature iPSCs. This review highlights the multifaceted roles of UTF1 and its implication in development, spermatogenesis, stem, and cancer cells.

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.

Evolving Role of RING1 and YY1 Binding Protein in the Regulation of Germ-Cell-Specific Transcription

Separation of germline cells from somatic lineages is one of the earliest decisions of embryogenesis. Genes expressed in germline cells include apoptotic and meiotic factors, which are not transcribed in the soma normally, but a number of testis-specific genes are active in numerous cancer types. During germ cell development, germ-cell-specific genes can be regulated by specific transcription factors, retinoic acid signaling and multimeric protein complexes. Non-canonical polycomb repressive complexes, like ncPRC1.6, play a critical role in the regulation of the activity of germ-cell-specific genes. RING1 and YY1 binding protein (RYBP) is one of the core members of the ncPRC1.6. Surprisingly, the role of Rybp in germ cell differentiation has not been defined yet. This review is focusing on the possible role of Rybp in this process. By analyzing whole-genome transcriptome alterations of the Rybp^-/- embryonic stem (ES) cells and correlating this data with experimentally identified binding sites of ncPRC1.6 subunits and retinoic acid receptors in ES cells, we propose a model how germ-cell-specific transcription can be governed by an RYBP centered regulatory network, underlining the possible role of RYBP in germ cell differentiation and tumorigenesis.

Practical Application of Lineage-Specific Immunohistochemistry Markers: Transcription Factors (Sometimes) Behaving Badly

CONTEXT.—

Transcription factors (TFs) are proteins that regulate gene expression and control RNA transcription from DNA. Lineage-specific TFs have increasingly been used by pathologists to determine tumor lineage, especially in the setting of metastatic tumors of unknown primary, among other uses. With experience gathered from its daily application and increasing pitfalls reported from immunohistochemical studies, these often-touted highly specific TFs are not as reliable as once thought.

OBJECTIVES.—

To summarize the established roles of many of the commonly used TFs in clinical practice and to discuss known and potential sources for error (eg, false-positivity from cross-reactivity, aberrant, and overlap "lineage-specific" expression) in their application and interpretation.

DATA SOURCES.—

Literature review and the authors' personal practice experience were used. Several examples selected from the University Health Network (Toronto, Ontario, Canada) are illustrated.

CONCLUSIONS.—

The application of TF diagnostic immunohistochemistry has enabled pathologists to better assess the lineage/origin of primary and metastatic tumors. However, the awareness of potential pitfalls is essential to avoid misdiagnosis.

Generation of pulmonary neuroendocrine cells and SCLC-like tumors from human embryonic stem cells

By blocking an important signaling pathway (called NOTCH) and interfering with expression of two tumor suppressor genes in cells derived from human embryonic stem cells, Chen et al. have developed a model for studying small cell lung cancers.

Cancer models based on cells derived from human embryonic stem cells (hESCs) may reveal why certain constellations of genetic changes drive carcinogenesis in specialized lineages. Here we demonstrate that inhibition of NOTCH signaling induces up to 10% of lung progenitor cells to form pulmonary neuroendocrine cells (PNECs), putative precursors to small cell lung cancers (SCLCs), and we can increase PNECs by reducing levels of retinoblastoma (RB) proteins with inhibitory RNA. Reducing levels of TP53 protein or expressing mutant KRAS or EGFR genes did not induce or expand PNECs, but tumors resembling early-stage SCLC grew in immunodeficient mice after subcutaneous injection of PNEC-containing cultures in which expression of both RB and TP53 was blocked. Single-cell RNA profiles of PNECs are heterogeneous; when RB levels are reduced, the profiles resemble those from early-stage SCLC; and when both RB and TP53 levels are reduced, the transcriptome is enriched with cell cycle–specific RNAs. Our findings suggest that genetic manipulation of hESC-derived pulmonary cells will enable studies of this recalcitrant cancer.

Knockdown of sal-like 4 expression by small interfering RNA induces apoptosis in breast cancer cells

Breast cancer is the most prevalent cancers worldwide and causes a significant amount of deaths annually. Spalt-like transcription factor 4 is known as a transcription factor, which has an important role in the proliferation of cancerous cells. Small interfering RNA (siRNA) is a short-chain molecule of 20 to 25 nucleotides that protrude on two sides of the 3', two nucleotides. In this study, using a specific sequence of siRNA against the sequence of this gene, its activity is investigated in the cell line of breast cancer. The breast cancer cells (MCF-7) were cultured and then, using a specific anti-sal-like 4 (SALL4) siRNA, their toxic doses were determined. Then, the gene is transfected into the cell. Proliferation and expression of the SALL4 and BCL-2 gene were measured using the real-time polymerase chain reaction method. The specific concentration of siRNA IC₅₀ of the SALL4 gene was 40.35 nmole. Gene expression results indicated that the expression of the Bcl-2 gene in the siRNA group was significantly reduced ( P < 0.05). SiRNA can increase the apoptosis of breast cancer cells by reducing the gene expression of SALL4 gene and Bcl-2; it can be used as a novel targeted therapy. This strategy, in addition to increasing the specificity of the drug, also reduces the side effects when compared with conventional chemotherapy.

Expression of RNA-binding protein LIN28 in classic gastric hepatoid carcinomas, gastric fetal type gastrointestinal adenocarcinomas, and hepatocellular carcinomas: An immunohistochemical study with comparison to SALL4, alpha-fetoprotein, glypican-3, and Hep Par1

INTRODUCTION

Gastric hepatoid carcinomas (GHCs) include type I (classic) and type II (fetal type gastrointestinal adenocarcinoma). The classic type shows overlapping morphologic features with those of hepatocellular carcinoma (HCC). The aim of this study is to investigate expression of LIN28 in GHCs and explore its utility to distinguish classic GHC from HCC.

METHODS

We investigated immunohistochemical expression of LIN28 in 93 primary GHCs (47 type I, 46 type II) and 60 HCCs with comparison to SALL4, AFP, glypican-3, Hep Par1, p-CEA and CK7. We also stained LIN28 and SALL4 in 52 conventional gastric adenocarcinomas to assess their specificity in gastric carcinomas.

RESULTS

Classic GHCs and fetal type gastrointestinal adenocarcinomas showed positive LIN28 in 21/47 (45%) and 10/46 (22%), SALL4 in 41/47 (87%) and 36/46 (78%), AFP in 30/46 (65%) and 33/46 (72%), glypican-3 in 31/41 (76%) and 24/38 (63%), Hep Par1 in 27/41 (66%) and 28/37 (76%), and CK7 in 15/40 (38%) and 25/38 (66%), respectively. p-CEA staining was seen in 19/44 (43%) classic GHCs. Among HCCs, LIN28, SALL4, AFP, glypican-3, Hep Par1, p-CEA and CK7 was seen in 1/60 (2%), 0/60 (0%), 6/30 (20%), 23/30 (77%), 29/30 (97%), 28/30 (93%) and 21/30 (70%) cases, respectively. LIN28 and SALL4 staining was seen in 2/52 (4%) and 14/52 (27%) gastric conventional adenocarcinomas, respectively. The sensitivity and specificity of distinguishing classic GHCs from HCCs was 45% and 98% for LIN28, 87% and 100% for SALL4, 65% and 80% for AFP, 76% and 30% for glypican-3, 66% and 3% for Hep Par1, 43% and 7% for p-CEA, and 38% and 30% for CK7, respectively. Combining LIN28 and SALL4 increased the sensitivity to 96% with 98% specificity to distinguish classic GHCs from HCCs.

CONCLUSIONS

LIN28 is a very specific marker (98% specificity) for distinguishing classic GHCs from HCCs though it is not as sensitive as SALL4. AFP, glypican-3, Hep Par1 and p-CEA are not useful in distinguishing classic GHCs from HCCs. Combining LIN28 and SALL4 increased the sensitivity to distinguish classic PHCs from HCCs.

Diallyl Trisulfide inhibits breast cancer stem cells via suppression of Wnt/β-catenin pathway

Cancer stem cells (CSCs) play a central role in the development of breast cancer. The canonical Wnt/β-catenin signal pathway is critical for maintaining CSCs characteristics. Diallyl trisulfide (DATS), a natural organosulfur compound from the garlic, exhibits effective antitumor properties. However, the role of DATS in regulating breast CSCs activity and the underlying molecular mechanisms remain obscure. In the present study, we reported that DATS efficiently inhibited the viability of breast CSCs as evidenced by reducing turmorspheres formation, decreasing the expression of breast CSCs markers (CD44, ALDH1A1, Nanog, and Oct4), as well as inhibiting proliferation and inducing apoptosis. Furthermore, we showed that DATS downregulated the activity of Wnt/β-catenin pathway, while LiCl-triggered Wnt/β-catenin activation diminished DATS inhibition on breast CSCs. Taken together, our results illustrated that DATS suppressed breast CSCs through inhibiting Wnt/β-catenin pathway activation. These novel findings could provide new insights into the molecular mechanisms of breast CSCs regulation as well as its target intervention and might provide new strategies for preventing and treating breast cancers.

Infrarenal high intra-abdominal testis: fusion of T2-weighted and diffusion-weighted magnetic resonance images and pathological findings

BACKGROUND

Several recent reports have demonstrated that the preoperative sensitivity and accuracy of identifying and locating non-palpable testes increases with the use of conventional MRI, in addition to diffusion-weighted imaging (DWI). Therefore, pre-operative prediction of the presence and location of testes using imaging techniques may guide management of intra-abdominal testis. Fowler-Stephens orchiopexy is effective for treating patients with intra-abdominal testis; however, long-term testicular function after this procedure has not been clarified. We present a case of a high intra-abdominal testis located below the kidney, and discuss the usefulness of fusion view with T2-weighted and DWI images to make a diagnosis of high intra-abdominal testis and the pathological findings to predict future fertility potential.

CASE PRESENTATION

A 10-month-old boy was referred to the urology department for the management of non-palpable testis. We employed not only conventional MRI, but also DWI, to improve the diagnostic accuracy of non-palpable testes by MRI examination. The high-intensity mass-like structure below the kidney on the T2-weighted image and the markedly high signal intensity mass on the DWI image completely matched, which suggested that the mass below the kidney was the right testis. The patient underwent diagnostic and therapeutic laparoscopy. A testis was found under the ascending colon, 1 cm below the right kidney. We performed 2-stage Fowler-Stephens orchiopexy. The testis could be delivered to the scrotum without any tension. We examined expression patterns of the stem cell marker, undifferentiated embryonic cell transcription factor 1 (UTF1) in the testicular biopsy sample, and demonstrated that the UTF1-positive Ad spermatogonia / negative Ad spermatogonia ratio was lower in this patient than in boys his age with descended and inguinal undescended testes, indicating that spermatogonial stem cell activity may decrease remarkably in this boy.

CONCLUSIONS

Fusion view with T2-weighted and DWI images may be a useful diagnostic modality for high intra-abdominal testes. Fowler-Stephens orchiopexy may provide blood supply to the testis but that might not be enough to achieve spermatogenesis.

Expression of OCT4 and SALL4 in Diffuse Large B-cell Lymphoma: An Analysis of 145 Consecutive Cases and Testicular Lymphomas

OCT4 and SALL4 are transcription factors within a complex network that functions to maintain pluripotency in primitive stem cells and germ cells. Nuclear expression of OCT4 is widely cited as sensitive and specific for primary and metastatic germ cell tumors and is commonly used in the diagnosis of central nervous system (CNS) germinomas. Studies have failed to systematically examine the expression of OCT4 or SALL4 in diffuse large B-cell lymphoma (DLBCL), although this entity enters the morphologic differential diagnosis of some germ cell tumors. A retrospective review was conducted on 145 consecutive cases of DLBCL and testicular lymphoma to evaluate the prevalence of OCT4 and SALL4 expression. Nuclear OCT4 expression was present in 2/11 (18%) testicular DLBCLs and 6/134 (4.5%) nontesticular DLBCLs. Most OCT4 cases demonstrated moderate to strong expression in >50% of neoplastic cells. Rare, weak nuclear SALL4 expression was detected in only 3 nontesticular DLBCLs. Within the extratesticular DLBCL group, 2/6 (33%) primary CNS DLBCLs expressed nuclear OCT4. In addition, OCT4 DLBCL showed an overall predilection toward non-germinal center B-cell phenotype (7/8; 88%) and had a higher than expected rate of CD5 coexpression (4/8, 50%). These results are cautionary against using OCT4 as a sole marker of germ cell differentiation in testicular and extratesticular sites, especially in the CNS. The apparent associations of OCT4 expression with primary CNS DLBCL, non-germinal center B-cell phenotype, and CD5 coexpression raise the question of whether OCT4 expression in DLBCL may reflect more aggressive biology.

Clinicopathological and molecular characterization of SMARCA4-deficient thoracic sarcomas with comparison to potentially related entities

A growing number of studies suggest critical tumor suppressor roles of the SWI/SNF chromatin remodeling complex in a variety of human cancers. The recent discovery of SMARCA4-deficient thoracic sarcomas has added to the list of tumor groups with the SMARCA4 inactivating mutation. To better characterize these tumors and establish their nosological status, we undertook a clinicopathological and molecular analysis of 12 SMARCA4-deficient thoracic sarcomas and compared them with three potentially related disease entities. Eleven men and one woman with SMARCA4-deficient thoracic sarcomas (aged 27-82 years, median 39 years) were included in the study. Most of the patients had heavy smoking exposure and pulmonary emphysema/bullae. The primary tumors were large and involved the thoracic region in all cases and simultaneously affected the abdominal cavity in 3 cases. The patients followed a rapid course, with a median survival of 7 months. Histologically, all tumors showed diffuse sheets of mildly dyscohesive, relatively monotonous, and undifferentiated epithelioid cells with prominent nucleoli. Immunohistochemically, all tumors demonstrated a complete absence (8 cases) or diffuse severe reduction (4 cases) of SMARCA4 expression. Cytokeratin, CD34, SOX2, SALL4, and p53 were expressed in 6/12, 10/12, 10/12, 10/12, and 7/10 cases, respectively. SMARCA2 expression was deficient in 11/12 cases, and none (0/8) expressed claudin-4. Targeted sequencing was performed in 5 cases and demonstrated the inactivating SMARCA4 mutation in each case and uncovered alterations in TP53 (5/5), NF1 (2/5), CDKN2A (2/5), KRAS (1/5), and KEAP1 (1/5), among others. Comparative analysis supported the distinctiveness of SMARCA4-deficient thoracic sarcomas as they were distinguishable from 13 malignant rhabdoid tumors, 15 epithelioid sarcomas, and 12 SMARCA4-deficient lung carcinomas based on clinicopathological and immunohistochemical grounds. SMARCA4-deficient thoracic sarcomas constitute a unique, highly lethal entity that requires full recognition and differentiation from other epithelioid malignancies involving the thoracic region.

Pineal germ cell tumors: Two cases with review of histopathologies and biomarkers

Pineal germ cell tumors (GCTs) are primarily seen in pediatric and Asian populations. These tumors are divided into germinomatous and non-germinomatous GCTs (NGGCTs). GCTs are thought to arise by misplacement of totipotent stem cells en route to gonads during embryogenesis. Intracranial GCTs display an affinity to develop along the pineal-suprasellar axis and have variable manifestations dependent upon the location of the tumor. Management and outcomes are driven by histopathologies. In this study, we highlight two cases of pineal GCTs and present a review of the literature with an emphasis on histopathologies and biomarkers.

Mediastinal seminoma associated with multilocular thymic cyst

An asymptomatic 26-year-old man received an annual medical check-up, and chest X-ray showed a protrusion of the aortopulmonary window. Chest computed tomography (CT) revealed an anterior mediastinal tumor and cysts with thin wall and septum enhancement. The preoperative diagnosis was cystic thymoma or malignant lymphoma. We performed total resection of the tumor through a median sternotomy. The pathological findings revealed seminoma, positive for c-kit stain, and multilocular thymic cysts. Cysts were lined by normal squamous epithelium and no seminoma cells were located on their surface. So, cysts were probably secondary changes caused by seminoma cells themselves or inflammatory stimulations. No invasion to adjacent structures was seen. After the surgery, testicular ultrasound imaging and abdominal, pelvic, and cerebral CT showed no apparent tumor or enlarged lymph nodes; however, an abnormal uptake in the right mesenteric lymph node was pointed out by ¹⁸F-fluorodeoxyglucose-positron emission tomography (FDG-PET) scan. The patient received four courses of bleomycin, etoposide, and cisplatin (BEP) as adjuvant chemotherapy. Follow-up PET scan revealed no uptake in the right mesenteric lymph node. To date, no recurrence or metastasis has been identified for 16 months.

SALL4 expression in gestational trophoblastic tumors: a useful tool to distinguish choriocarcinoma from placental site trophoblastic tumor and epithelioid trophoblastic tumor

SALL4 has important functions in embryonic stem cells. The aim of this study was to investigate SALL4 expression in gestational trophoblastic neoplasia. We hypothesized that it could help to distinguish choriocarcinoma, the presumed most primitive form of gestational trophoblastic neoplasia, from placental site trophoblastic tumor and epithelioid trophoblastic tumor, which would be more differentiated variants. This study included 31 gestational trophoblastic neoplasias: 19 choriocarcinomas, 9 placental site trophoblastic tumors, 1 epithelioid trophoblastic tumor, and 2 mixed tumors comprising a placental site trophoblastic tumor and an epithelioid trophoblastic tumor. Unlike usual markers of gestational trophoblastic neoplasia (p63, human chorionic gonadotrophin and human placental lactogen), SALL4 was expressed in 100% of choriocarcinomas and it was not detected in any placental site trophoblastic tumor and epithelioid trophoblastic tumor. However, the proportion of positive cells varied in a wide range, from 10% to 70%, reflecting the fact that SALL4 was specifically present in mononuclear cells consistent with neoplastic cytotrophoblast. So, SALL4 may be helpful in the differential diagnosis of gestational trophoblastic neoplasias.

Histatin-1 Expression in Human Lacrimal Epithelium

Background

Study of human lacrimal cell biology is limited by poor access to tissue samples, heterogeneous cell composition of tissue and a lack of established lacrimal epithelial markers. In order to further our understanding of lacrimal cell biology, we sought to find a better marker for human lacrimal epithelial cells, compared to what has been reported in the literature.

Methods

We utilized human Muller’s muscle conjunctival resection (MMCR) specimens containing accessory lacrimal gland (ALG) and cadaveric main lacrimal gland (MLG) as sources of lacrimal tissue. Candidate markers were sought using human ALG tissue from MMCR specimens, isolated by laser capture microdissection (LCM). Affymetrix® analysis was performed on total RNA isolated from FFPE samples to profile transcription in ALG. MMCR tissue sections were assessed by immunofluorescence using antibodies for histatin-1, lactoferrin, E-cadherin (E-cad) and alpha-smooth muscle actin (ASMA). Reverse transcriptase polymerase chain reaction (RT-PCR) analysis was performed to analyze the expression of histatin-1, E-cad and lactoferrin from cadaveric MLG.

Results

Histatin-1 is expressed in ALG and MLG, localizes to lacrimal epithelium, and to a greater degree than do other putative lacrimal epithelial markers.

Conclusions

Histatin-1 is a good marker for human lacrimal epithelium in ALG and MLG and can be used to identify lacrimal cells in future studies.

The zinc-finger transcription factor SALL4 is frequently expressed in human cancers: association with clinical outcome in squamous cell carcinoma but not in adenocarcinoma of the esophagus

SALL4 is a transcription factor originally identified as a homeotic gene essential for organ development. Early studies suggested that SALL4 is a useful marker to identify testicular and ovarian germ cell tumors. The aim of the study was to evaluate the diagnostic potential of SALL4 immunohistochemistry. Immunohistochemical staining was performed on a tissue microarray (TMA) with 3966 samples from 94 different tumor types and on a further TMA with 492 esophagus carcinomas. SALL4 immunostaining was by far most prevalent and most intensive in testicular tumors with a positivity rate of 93.1% in seminomas, 80% in mixed germ cell tumors (embryonic carcinomas/yolk sac tumors), and 18.5% in teratomas, respectively. However, SALL4 expression is not specific to germ cell tumors. We observed SALL4 positivity in non-germ cell tumors as carcinomas of the kidney (28.9% of chromophobe, 34.4% of clear cell carcinoma), in intestinal type adenocarcinoma of the stomach (10.9%), in adenocarcinoma (10.5%) and squamous cell carcinoma (7.2%) of the esophagus, and in malignant melanoma (8.1%) and invasive urothelial bladder carcinoma (20%). SALL4 expression was not found in lymphomas, in soft tissue tumors or breast tumors. At analysis of esophagus carcinoma TMA, no significant association was seen between SALL4 expression and overall survival in adenocarcinoma. However, SALL4 expression was strongly associated with worse overall survival in squamous cell carcinoma. SALL4 expression can be found at relevant frequencies in various tumors of different primary sites. SALL4 expression in squamous cell carcinoma of the esophagus may constitute a sign of dedifferentiation leading to poor patient prognosis.

Medulloepithelioma with peculiar clinical presentation, stem cell phenotype and aberrant DNA-methylation profile

We present a 21-year-old male with a neck mass diagnosed as medulloepithelioma. Despite aggressive chemo- and radio-therapy, the tumor metastasized and proved fatal after seventeen months. The tumor demonstrated robust immunohistochemical expression of multiple markers of embryonic/neural stem cells and embryogenesis from the paraffin embedded tissue. The tumor, expressing LIN28A but negative for the 19q13.42 amplicon, also lacked the characteristic methylation profile for medulloepithelioma and other tumors with similar morphology. The expression of embryonic markers may explain its unresponsiveness to therapy and poor prognosis. Therapies targeted at embryonic cell phenotypes may hold the key for successfully treating cancers with embryonal phenotypes or tumors harboring cells with embryonal phenotypes.

The embryonic stem cell factor UTF1 serves as a reliable diagnostic marker for germinomas

The transcription factor OCT4 is an established diagnostic marker for central nervous system (CNS) germinoma. However, no data are available to date concerning the expression of its downstream target undifferentiated embryonic cell transcription factor 1 (UTF1) in CNS germ cell tumours. We examined 21 CNS germinomas and two mixed CNS germ cell tumours for UTF1 and the post-transcriptional regulator LIN28 immunohistochemical expression. We compared the profile to established diagnostic germinoma markers and to the expression in six testicular and four metastatic germ cell tumours as well as 150 CNS tumours of various backgrounds. We found UTF1 expression in 23 of 23 and LIN28 in 20 of 23 CNS germ cell tumours. The established germinoma markers cKIT (23/23), OCT4 (21/23) and placental alkaline phosphatase (PLAP) (19/21) were also frequently expressed in our cohort. In terms of signal intensity and frequency, UTF1 showed similar results as cKIT but staining was superior to OCT4, PLAP and LIN28. OCT4 was absent in all CNS metastases and haemangioblastomas, while UTF1 was weakly observed in two metastases.With a sensitivity of 100% and a specificity of 97% in the detection of CNS germinomas, UTF1 serves as a new reliable alternative in the diagnostic setting of CNS germ cell tumours.

Primary mediastinal seminomas: a comprehensive immunohistochemical study with a focus on novel markers

Primary mediastinal seminomas are unusual tumors that can present in a pure form or as part of a mixed germ cell tumor. Contrary to testicular seminomas, little is known about the expression of novel immunohistochemical markers in mediastinal seminomas. This study investigates the immunohistochemical features of these tumors with a focus on novel markers. Thirty-two cases of primary mediastinal seminomas were reviewed; and representative whole-tissue sections were selected for immunohistochemical studies using antibodies directed against high molecular weight cytokeratin 5/6 (CK5/6), low molecular weight cytokeratin (CAM5.2), octamer-binding transcription factor 3/4 (OCT3/4), spalt-like transcription factor 4 (SALL4), GATA binding protein 3 (GATA-3), sry-related HMG box 2 (SOX2), SOX17, human T cell leukemia/lymphoma 1 (TCL1), glypican 3, melanoma associated antigen C2 (MAGEC2), and paired box gene 8 (Pax8). The percentage of positive tumor cells as well as the intensity of staining was evaluated and scored. Thirty-one cases (97%) expressed SOX17, whereas 29 cases (91%) were positive for OCT3/4 and SALL4, respectively. Twenty-eight cases (88%) expressed MAGEC2 and CAM5.2, respectively. Two cases (6%) were positive for Pax8, and a single case (3%) was positive for TCL1. None of the cases stained with CK5/6, GATA-3, SOX2, or glypican 3. Similar to testicular seminomas, mediastinal seminomas show consistent expression of OCT3/4, SALL4, SOX17, and MAGEC2 and are negative for SOX2, glypican 3, GATA-3, and CK5/6. Pax8 positivity is only inconsistently identified in mediastinal seminomas. Contrary to their testicular counterparts, mediastinal tumors show diffuse expression of low-molecular-weight cytokeratin in up to 90% of cases and are commonly negative for TCL1. Although there is some immunohistochemical overlap between testicular and mediastinal seminomas, considerable differences also exist and should be acknowledged when dealing with these tumors.

Immunohistochemistry in undifferentiated neoplasm/tumor of uncertain origin

CONTEXT

Immunohistochemistry has become an indispensable ancillary study in the identification and classification of undifferentiated neoplasms/tumors of uncertain origin. The diagnostic accuracy has significantly improved because of the continuous discoveries of tissue-specific biomarkers and the development of effective immunohistochemical panels.

OBJECTIVES

To identify and classify undifferentiated neoplasms/tumors of uncertain origin by immunohistochemistry.

DATA SOURCES

Literature review and authors' research data and personal practice experience were used.

CONCLUSIONS

To better guide therapeutic decisions and predict prognostic outcomes, it is crucial to differentiate the specific lineage of an undifferentiated neoplasm. Application of appropriate immunohistochemical panels enables the accurate classification of most undifferentiated neoplasms. Knowing the utilities and pitfalls of each tissue-specific biomarker is essential for avoiding potential diagnostic errors because an absolutely tissue-specific biomarker is exceptionally rare. We review frequently used tissue-specific biomarkers, provide effective panels, and recommend diagnostic algorithms as a standard approach to undifferentiated neoplasms.

The Utility of Immunohistochemistry in the Differential Diagnosis of Gynecologic Disorders

Context

Immunohistochemistry has assumed an increasing role in the identification and characterization of gynecologic disorders including lesions with deceptively bland morphology, uncommon and underdiagnosed neoplasms, and neoplasms with specific genetic alterations associated with overexpression or loss of expression of specific proteins. The diagnostic accuracy has been significantly improved owing to the discovery and increasing experience with the tumor-associated biomarkers, and the increasing demand for precise tumor classification to assess suitability for the expanding therapeutic modalities including clinical trials.

Objective

To differentiate lesions of the gynecologic tract through the use of effective immunohistochemical panels.

Data Sources

Literature review and authors' personal practice experience.

Conclusions

The application of diagnostic and prognostic immunohistochemical panels has enabled pathologists to better guide therapeutic decisions and to better predict the clinical outcome. It is now well established that the use of ancillary testing, including immunohistochemistry, has a significant power in the identification, differentiation, and classification of reactive, premalignant, and malignant gynecologic disorders. This article discusses the utilities and pitfalls of the commonly used immunohistochemical markers in the context of overlapping morphologic features encountered in the uterus, ovaries, and fallopian tubes.

Expression of undifferentiated embryonic cell transcription factor-1 (UTF1) in breast cancers and their matched normal tissues

Objectives

Undifferentiated embryonic cell transcription factor-1 (UTF1) plays a critical role in the developmental timing during embryonic development. However, there is little paper dealing with UTF1 expressed in adult tissues. In the present study, we evaluate the expression of UTF1 in breast cancer and its correlation with clinicopathological parameters.

Methods

Real-time polymerase chain reaction (real-time PCR) was applied to detect the expression of UTF1 mRNA in the 55 pairs of samples of breast cancer tissues and match normal tissues. △△CT method was used to evaluate the relative quantity of target mRNA expression.

Results

Among the 55 pairs of samples of breast cancer tissues and match normal tissues adjacent to the tumor, the UTF1 mRNA levels in normal tissues were significantly higher than those observed in breast cancer tissues (p < 0.001). UTF1 mRNA levels expression correlated with lymph node metastasis (p = 0.002) and tumor size (p < 0.001).

Conclusions

Expression of UTF1 in breast cancer tissues were confirmed in this study. Decreased expression of UTF1 mRNA in breast cancer tissues was maybe one of the factors impact on tumorigenes in breast cancer patients.

Discovery and diagnostic value of a novel oncofetal protein: glypican 3

Glypican 3 is a membrane-bound heparan sulfate proteoglycan, which has recently been identified as a marker for liver cancer and germ cell malignancies. Individuals with loss-of-function mutations for the glypican 3 gene exhibit Simpson-Golabi-Behmel syndrome, a rare X-linked overgrowth disorder. Expression of glypican 3 mRNA and protein is normally silenced in most adult organs and may reappear during malignant transformation. In the past few years, immunohistochemical and molecular characteristics of glypican 3 in hepatocellular carcinoma have been elucidated. More recently, glypican 3 has been emerging as a new diagnostic marker for germ cell tumors and especially testicular and ovarian yolk sac tumors. However, in other tumors such as renal cell carcinomas, squamous cell carcinomas, and melanomas, studies disagree on the level of glypican 3 expression. Finally, there is the controversial notion of glypican 3 as a tumor suppressor gene. In this review article, we update current knowledge on glypican 3 expression in normal and neoplastic tissues, evaluate its utility as a tumor marker in clinical practice, and explore its role as a novel oncofetal protein with clinical implications. Our focus is on the diagnostic value of glypican 3 in germ cell tumors and other neoplasms in addition to hepatocellular carcinoma. In conclusion, glypican 3 has been proven to be a useful immunohistochemical marker in distinguishing yolk sac tumors, choriocarcinomas, and Wilms tumors from other malignancies histologically mimicking these primitive tumors. Clinically, we recommend that glypican 3 be used as part of a panel of markers in subtyping testicular germ cell tumors.