GATA3 expression in gestational trophoblastic tissues and tumours

Can immunohistochemistry improve the pathological diagnosis of placenta accreta spectrum (PAS) disorders?

PURPOSE

The term of placenta accreta spectrum (PAS) disorder includes all grades of abnormal placentation. It is crucial for pathologist provide standardized diagnostic assessment to evaluate the outcome of management strategies. Moreover, a correct and safe diagnosis is useful in the medico-legal field when it becomes difficult for the gynecologist to demonstrate the suitability and legitimacy of demolitive treatment. The purposes of our study were: (1) to assess histopathologic features according to the recent guidelines; (2) to determine if immunohistochemistry can be useful to identify extravillous trophoblast (EVT) and to measure the depth of infiltration into the myometrium to improve the diagnosis of PAS.

METHODS

The retrospective study was conducted on 30 cases of gravid hysterectomy with histopathologic diagnosis of PAS. To identify the depth of EVT, immunohistochemical stainings were performed using anti MNF116 (cytokeratins 5, 6, 8, 17, 19), actin-SM, HPL (Human Placental Lactogen), vimentin and GATA3 antibodies.

RESULTS

Our cases were graded based on the degree of invasion of the myometrium. Ten were grade 1 (33.3%), 12 grade 2 (40%) and 8 grade 3A (26.7%). EVT invasion was best seen and evident by double immunostainings with actin-SM and cytokeratins, actin-SM and HPL, actin-SM and GATA3.

CONCLUSION

The role of pathologist is decisive to determine the different grades of PAS. A better understanding of the depth of myometrial invasion can be achieved by the use of immunohistochemistry affording an important tool to obtain reproducible grading of PAS. This purpose is crucial in the setting of postoperative quality reviews and particularly in the forensic medicine field.

GATA3 and TGF-β in normal placenta and pre-eclampsia

GATA3 plays critical roles in the development and function of various tissues and organs throughout the body. Likewise, TGF-β signaling is critical for placental development and can interact with GATA3. We aimed to investigate the involvement of the multifunctional cytokine and transcription factor in trophoblast development. By using immunohistochemistry, we evaluated the localization and expression level of GATA3 and TGF-β in placentas at term of normal pregnancy and with pre-eclampsia. Up-regulation of both GATA3 and TGF-β was observed in pathological placentas, with localization in the villus epithelium (syncytiotrophoblast) stroma and decidua. Our data show altered expression of TGF-β and GATA3, which downstream could lead to a cascade of events that negatively influence trophoblast development and contribute to the pathogenesis of pre-eclampsia.

Controlling placental spheroid growth and phenotype using engineered synthetic hydrogel matrices

The human placenta is a complex organ comprised of multiple trophoblast subtypes, and inadequate models to study the human placenta in vitro limit the current understanding of human placental behavior and development. Common in vitro placental models rely on two-dimensional culture of cell lines and primary cells, which do not replicate the native tissue microenvironment, or poorly defined three-dimensional hydrogel matrices such as Matrigel™ that provide limited environmental control and suffer from high batch-to-batch variability. Here, we employ a highly defined, synthetic poly(ethylene glycol)-based hydrogel system with tunable degradability and presentation of extracellular matrix-derived adhesive ligands native to the placenta microenvironment to generate placental spheroids. We evaluate the capacity of a hydrogel library to support the viability, function, and phenotypic protein expression of three human trophoblast cell lines modeling varied trophoblast phenotypes and find that degradable synthetic hydrogels support the greatest degree of placental spheroid viability, proliferation, and function relative to standard Matrigel controls. Finally, we show that trophoblast culture conditions modulate cell functional phenotype as measured by proteomics analysis and functional secretion assays. Engineering precise control of placental spheroid development in vitro may provide an important new tool for the study of early placental behavior and development.

Trophoblast stem cell-based organoid models of the human placental barrier

Human placental villi have essential roles in producing hormones, mediating nutrient and waste exchange, and protecting the fetus from exposure to xenobiotics. Human trophoblast organoids that recapitulate the structure of villi could provide an important in vitro tool to understand placental development and the transplacental passage of xenobiotics. However, such organoids do not currently exist. Here we describe the generation of trophoblast organoids using human trophoblast stem (TS) cells. Following treatment with three kinds of culture medium, TS cells form spherical organoids with a single outer layer of syncytiotrophoblast (ST) cells that display a barrier function. Furthermore, we develop a column-type ST barrier model based on the culture condition of the trophoblast organoids. The bottom membrane of the column is almost entirely covered with syndecan 1-positive ST cells. The barrier integrity and maturation levels of the model are confirmed by measuring transepithelial/transendothelial electrical resistance (TEER) and the amount of human chorionic gonadotropin. Further analysis reveals that the model can be used to derive the apparent permeability coefficients of model compounds. In addition to providing a suite of tools for the study of placental development, our trophoblast models allow the evaluation of compound transfer and toxicity, which will facilitate drug development.

Gene of the month: GATA3

GATA binding protein 3 (GATA3) is a zinc-finger pioneer transcription factor involved in diverse processes. GATA3 regulates gene expression through binding nucleosomal DNA and facilitating chromatin remodelling. Post-translational modifications modulate its activity. During development, GATA3 plays a key role in cell differentiation. Mutations in GATA3 are linked to breast and bladder cancer. GATA3 expression is a feature of the luminal subtype of bladder cancer and has implications for immune status and therapeutic response. It also has clinical relevance in squamous cell carcinomas and soft tissue sarcomas. This paper reviews the structure and function of GATA3, its role in cancer and its use and pitfalls as an immunohistochemical marker.

Diagnostic Utility of TSSC3 and RB1 Immunohistochemistry in Hydatidiform Mole

The general notion of complete hydatidiform moles is that most of them consist entirely of paternal DNA; hence, they do not express p57, a paternally imprinted gene. This forms the basis for the diagnosis of hydatidiform moles. There are about 38 paternally imprinted genes. The aim of this study is to determine whether other paternally imprinted genes could also assist in the diagnostic approach of hydatidiform moles. This study comprised of 29 complete moles, 15 partial moles and 17 non-molar abortuses. Immunohistochemical study using the antibodies of paternal-imprinted (RB1, TSSC3 and DOG1) and maternal-imprinted (DNMT1 and GATA3) genes were performed. The antibodies' immunoreactivity was evaluated on various placental cell types, namely cytotrophoblasts, syncytiotrophoblasts, villous stromal cells, extravillous intermediate trophoblasts and decidual cells. TSSC3 and RB1 expression were observed in all cases of partial moles and non-molar abortuses. In contrast, their expression in complete moles was identified in 31% (TSSC3) and 10.3% (RB1), respectively (p < 0.0001). DOG1 was consistently negative in all cell types in all cases. The expressions of maternally imprinted genes were seen in all cases, except for one case of complete mole where GATA3 was negative. Both TSSC3 and RB1 could serve as a useful adjunct to p57 for the discrimination of complete moles from partial moles and non-molar abortuses, especially in laboratories that lack comprehensive molecular service and in cases where p57 staining is equivocal.

Expression of type VI collagen α3 chain in canine mammary carcinomas

This study aimed to investigate the expression of type VI collagen α3 chain (COL6a3) in neoplastic cells of canine mammary gland carcinomas (CMGCs) using immunohistochemistry (IHC) and to evaluate the association between COL6a3 expression and tumor histological features, histological grades, and the differentiation status of neoplastic epithelial cells. COL6a3 expression in carcinoma cells was significantly associated with histologically low malignancy and low mitotic indices. In addition, COL6a3+ carcinoma cells were more frequently detected in simple carcinomas (tubular and tubulopapillary types) than in solid carcinomas. These findings indicate that reduced expression of COL6a3 in carcinoma cells contributes to the malignant phenotype in CMGCs. We also showed that COL6a3 expression in the carcinoma cells was more frequently detected in CK19+/CD49f + and/or CK19+/CK5+ tumors. In addition, COL6a3+/CK19+/CD49f + and COL6a3+/CK19+/CK5+ tumors consisted of CK19+/CD49f + and CK19+/CD49f- cells, and CK19+/CK5+ and CK19+/CK5- cells, respectively. Most of these tumors more frequently expressed GATA3, but not Notch1. These results indicate that COL6a3 is expressed in CMGCs containing both luminal progenitor-like and mature luminal-like cells and showing differentiation ability into mature luminal cells. It is possible that COL6 may be involved in the differentiation of luminal progenitor-like carcinoma cells into mature luminal-like carcinoma cells in CMGCs, which may suppresses the development of malignant phenotypes in CMGCs.

GATA3 Expression in Human Tumors: A Tissue Microarray Study on 16,557 Tumors

INTRODUCTION

GATA3 is a transcription factor involved in epithelial cell differentiation. GATA3 immunostaining is used as a diagnostic marker for breast and urothelial cancer but can also occur in other neoplasms.

METHODS

To evaluate GATA3 in normal and tumor tissues, a tissue microarray containing 16,557 samples from 131 different tumor types and subtypes and 608 samples of 76 different normal tissue types was analyzed by immunohistochemistry.

RESULTS

GATA3 positivity was found in 69 different tumor types including 23 types (18%) with at least one strongly positive tumor. Highest positivity rates occurred in noninvasive papillary urothelial carcinoma (92-99%), lobular carcinoma (98%), carcinoma of no special type of the breast (92%), basal cell carcinoma of the skin (97%), invasive urothelial carcinoma (73%), T-cell lymphoma (23%), adenocarcinoma of the salivary gland (16%), squamous cell carcinoma of the skin (16%), and colorectal neuroendocrine carcinoma (12%). In breast cancer, low GATA3 staining was linked to high pT stage (p = 0.03), high BRE grade (p < 0.0001), HER2 overexpression (p = 0.0085), estrogen and progesterone receptor negativity (p < 0.0001 each), and reduced survival (p = 0.03).

CONCLUSION

Our data demonstrate that GATA3 positivity can occur in various tumor entities. Low levels of GATA3 reflect cancer progression and poor patient prognosis in breast cancer.

Expression of receptor-type tumour endothelial marker 8 in carcinoma cells showing luminal progenitor-like phenotypes in canine mammary gland carcinomas

This study aimed to investigate the expression of receptor-type tumour endothelial marker 8 (TEM8RT) in canine mammary gland carcinomas (CMGCs) using immunohistochemistry and to evaluate the association between carcinoma cell TEM8RT expression and tumour histological features, histological grades and the differentiation status of neoplastic epithelial cells. TEM8RT expression was more frequently detected in simple carcinomas (tubular and tubulopapillary) than in solid carcinomas, and it was significantly correlated with histological grade Ⅰ tumours and a low mitotic index. Additionally, TEM8RT⁺ carcinoma cells were more frequently found in CMGCs showing luminal progenitor-like phenotypes, such as Notch1⁺, CK19⁺/CK5⁺/CD49f⁺ and CK19⁺/CK5^-/CD49f⁺. Double-labelling immunofluorescence detection techniques confirmed that most TEM8RT⁺ carcinoma cells expressed CD49f, Notch1 and CK19. However, TEM8RT immunoreactivity was not found in carcinoma cells expressing GATA3, which upregulates mature luminal cell differentiation. Furthermore, TEM8RT⁺ carcinoma cells were detected in a few CMGCs showing basal/stem cell-like phenotypes such as CK19^-/CK5⁺/CD49f⁺ and CK19^-/CK5⁺/CD49f^-. These findings indicate that TEM8RT is expressed in luminal progenitor-like carcinoma cells in CMGCs. Since TEM8 enhances self-renewal in human mammary stem/progenitor cells, it also may be involved in maintenance of luminal progenitor-like carcinoma cells, resulting in prevention of their transition to basal/stem cell-like carcinoma cells and development of less malignant CMGCs. Therefore, TEM8RT may be useful for indicating prognostic outcomes and identifying the possible ontogeny of carcinoma cells in mammary gland tumours.

Clinicopathologic and Molecular Characteristics of and Diagnostic Dilemmas in Invasive Breast Carcinoma with Choriocarcinomatous Pattern apropos a New Case: A Literature Review with New Findings

BACKGROUND

Invasive breast carcinoma with a choriocarcinomatous pattern (IBC-CP) is extremely rare, and its molecular basis is yet unclear. The choriocarcinomatous pattern is characterized by the biphasic arrangement of multinucleated syncytiotrophoblast-like cells around clusters of monotypic tumor cells in a hemorrhagic background, along with β-human chorionic gonadotropin (β-hCG) expression. The differentiation of IBC-CP from metastatic choriocarcinoma of the breast (MC-B) is difficult due to the histologic similarity.

METHODS

Based on a literature review and our own case, the clinicopathologic differences between IBC-CP patients (n = 17) and MC-B patients (n = 8) were analyzed. Moreover, in our case of IBC-CP, next-generation sequencing (NGS) comparative analysis was conducted for both choriocarcinomatous and invasive breast carcinoma (IBC) components.

RESULTS

Compared to the MC-B patients, the IBC-CP patients were older (p < 0.001) and less frequently had past histories of gestational trophoblastic disease/pregnancy/abortion (p = 0.001) and distant metastases (p = 0.005). Our case, a 49-year-old female patient, presented with masses in the right breast and axilla. Following neoadjuvant chemotherapy, a radical mastectomy found an 8.5-cm-sized tumor. Microscopically, multinucleated syncytiotrophoblast-like cells were observed around mononuclear tumor cells with hemorrhage and necrosis. Some tumor cells showed β-hCG immunopositivity, which was compatible with IBC-CP. NGS results showed a missense mutation in exon 5 of the TP53 gene in both the choriocarcinomatous and IBC components. Meanwhile, copy number loss in the PTEN gene was only identified in the choriocarcinomatous components.

CONCLUSION

The present IBC-CP case is triple-negative breast cancer with TP53 mutation. The PTEN gene may be associated with choriocarcinomatous differentiation. Obtaining a medical history is mandatory to exclude metastatic lesions.

Gestational Trophoblastic Disease: Contemporary Diagnostic Approach

Pathologic diagnosis of gestational trophoblastic disease (GTD)-hydatidiform moles and gestational trophoblastic neoplasms-underwent a major shift in the past decade from morphology-based recognition to precise molecular genetic classification of entities, which also allows for prognostic stratification of molar gestations. This article highlights these recent advances and their integration into the routine pathology practice. The traditional gross and histomorphologic features of each entity are also reviewed with special focus on differential diagnoses and their clinical implications.

Role of GATA3 in tumor diagnosis: A review

GATA binding protein 3 (GATA3) belongs to a family of transcription factors comprising six members. These proteins identify G-A-T-A containing sequences in the target gene and bind to DNA target via two zinc-finger domains. The aim of this study was to evaluate the role of GATA3 in the diagnosis of tumors and its value as a prognostic marker. To perform this review, a comprehensive search was conducted through PubMed, Embase, Scopus, Cochrane and Google Scholar databases from 1985 to 2020. Articles were considered thoroughly by independent reviewers and data were extracted in predefined forms. Final synthesis was conducted by using appropriate data from included articles in each topic. Studies have shown that GATA3 has a critical role in the development of epithelial structures in both embryonic and adult tissues. The majority of studies regarding GATA3 expression in tumor evaluation focused on breast and urothelial neoplasms, whether primary or metastatic. Its sensitivity in these neoplasms has been reported to be high and made this marker more valuable than other available immunohistochemistry markers. However, GATA3 expression was not restricted to these tumors. Studies have shown that GATA3 immunostaining could be a useful tool in various tumors in kidney, salivary gland, endocrine system, hematopoietic system, and skin. GATA3 can also be used as a useful prognostic tool. Although GATA3 is a multi-specific immunohistochemical stain, it is a valuable marker in the panel for confirming many epithelial or mesenchymal neoplasms as both a diagnostic and prognostic tool.

Aerobic Vaginitis Induced by Escherichia coli Infection During Pregnancy Can Result in Adverse Pregnancy Outcomes Through the IL-4/JAK-1/STAT-6 Pathway

Aerobic vaginitis (AV) can occur if normal vaginal microflora are dominated by aerobic bacteria, seriously affects not only female health, but also fetal health while they are pregnant. Besides, pregnant status also aggravates the symptoms and consequences of the infection. Here, we infected pregnant BALB/c mice with Escherichia coli on embryonic day 4.5 (E4.5) (study group), and administered an equivalent volume of phosphate-buffered saline in another cohort of pregnant mice (control group). We recorded the weight of pregnant mice and their fetuses. The maternal and fetal weight of the study group decreased in comparison with that of the control group, whereas the weight of placenta increased in the study group. Then, five genes with significant upregulation and 15 genes with downregulation were screened. Expression of interleukin 4 (IL-4) mRNA in the study group decreased to 18.5%. Enzyme-linked immunosorbent assay results showed IL-4 expression in mouse plasma declined in the study group at E11.5 and E18.5. mRNA expression of chemokine (c-c motif) ligand (CCL)-17, CCL-22, CCL-24, IL-4, Janus Kinase (JAK)-1, signal transducer and activator of transcription (STAT)-6, and GATA-3 showed significant downregulation in placental and uterine tissues. Flow cytometry of primary decidual macrophages (DMs) revealed more M1-like macrophages in the study group. And after addition of IL-4 to DMs, more M1 macrophages polarized to M2 type macrophages. We did not discover bacteria existed in mouse placentas. Our study affords a feasible method for exploring and managing AV during pregnancy.

Distinct microRNA profiles for complete hydatidiform moles at risk of malignant progression

BACKGROUND

MicroRNAs are small noncoding RNAs with important regulatory functions. Although well-studied in cancer, little is known about the role of microRNAs in premalignant disease. Complete hydatidiform moles are benign forms of gestational trophoblastic disease that progress to gestational trophoblastic neoplasia in up to 20% of cases; however, there is no well-established biomarker that can predict the development of gestational trophoblastic neoplasia.

OBJECTIVE

This study aimed to investigate possible differences in microRNA expression between complete moles progressing to gestational trophoblastic neoplasia and those regressing after surgical evacuation.

STUDY DESIGN

Total RNA was extracted from fresh frozen tissues from 39 complete moles collected at the time of uterine evacuation in Brazil. In the study, 39 cases achieved human chorionic gonadotropin normalization without further therapy, and 9 cases developed gestational trophoblastic neoplasia requiring chemotherapy. Total RNA was also extracted from 2 choriocarcinoma cell lines, JEG-3 and JAR, and an immortalized normal placenta cell line, 3A-subE. MicroRNA expression in all samples was quantified using microRNA sequencing. Hits from the sequencing data were validated using a quantitative probe-based assay. Significantly altered microRNAs were then subjected to target prediction and gene ontology analyses to search for alterations in key signaling pathways. Expression of potential microRNA targets was assessed by quantitative real-time polymerase chain reaction and western blot. Finally, potential prognostic protein biomarkers were validated in an independent set of formalin-fixed paraffin-embedded patient samples from the United States (15 complete moles progressing to gestational trophoblastic neoplasia and 12 that spontaneously regressed) using quantitative immunohistochemistry.

RESULTS

In total, 462 microRNAs were identified in all samples at a threshold of <1 tag per million. MicroRNA sequencing revealed a distinct set of microRNAs associated with gestational trophoblastic neoplasia. Gene ontology analysis of the most altered transcripts showed that the leading pathway was related to response to ischemia (P<.001). Here, 2 of the top 3 most significantly altered microRNAs were mir-181b-5p (1.65-fold; adjusted P=.014) and mir-181d-5p (1.85-fold; adjusted P=.014), both of which have been shown to regulate expression of BCL2. By quantitative real-time polymerase chain reaction, BCL2 messenger RNA expression was significantly lower in the complete moles progressing to gestational trophoblastic neoplasia than the regressing complete moles (-4.69-fold; P=.018). Reduced expression of BCL2 was confirmed in tissue samples by western blot. Immunohistochemistry in the independent patient samples revealed significantly lower cytoplasmic expression of BCL2 in the villous trophoblasts from cases destined for progression to gestational trophoblastic neoplasia compared with those that regressed, both with respect to staining intensity (optic density 0.110±0.102 vs 0.212±0.036; P<.001) and to the percentage of positive cells (16%±28% vs 49.4%±28.05%; P=.003).

CONCLUSION

Complete moles progressing to gestational trophoblastic neoplasia are associated with a distinct microRNA profile. miR-181 family members and BCL2 may be prognostic biomarkers for predicting gestational trophoblastic neoplasia risk.

Clinical Applications of Immunohistochemistry in Germ Cell Tumors in Men

Germ cell tumors (GCT) in men comprise of tumor subtypes with distinct histomorphologies, genetic and genomic alterations, and clinical behavior. Immunohistochemical (IHC) markers, including many newly described nuclear transcription factors, are often applied in challenging cases to arrive at a correct diagnosis and classification, and to establish germ cell origin for metastatic tumors. However, there is no established role for IHC markers in prognosis and therapy response prediction in GCTs. This chapter briefly reviews the clinical utility of IHC in diagnosis and classification of GCTs, including technical aspects of performing IHC and clinical applications of commonly used IHC markers in the workup of common and clinically relevant diagnostic scenarios.

Epithelioid Trophoblastic Tumor: Expanding the Clinicopathologic Spectrum of a Rare Malignancy

Epithelioid trophoblastic tumor is a malignancy derived from the chorionic laeve-type intermediate trophoblast with sufficient rarity that the vast majority of literature on the topic exists in the form of case reports and small series. Classically, it is regarded as a well-circumscribed tumor with an expansile growth pattern that occurs in reproductive-aged women, usually after a normal pregnancy. However, we recently encountered a case of epithelioid trophoblastic tumor with aggressive spread throughout the abdomen and pelvis in a 68-yr-old female presenting 30 yr after her last delivery. Although to our knowledge this is the first report in a postmenopausal patient to be confirmed by molecular analysis of short tandem repeats, there are multiple similar case reports spanning a variety of clinical settings that deviate from the original description. We therefore sought to synthesize the clinicopathologic data among the available reports in the English literature, with emphasis on pathologic findings. While the overarching themes are largely unchanged, this series of 77 patients reveals a broader spectrum of disease and highlights frequent misdiagnosis. Here we present a clinicopathologic update on this rare entity, with emphasis on a practical approach to diagnosis.

A Comprehensive Review of Biomarker Use in the Gynecologic Tract Including Differential Diagnoses and Diagnostic Pitfalls

Morphologic (ie, hematoxylin and eosin) evaluation of the Mullerian tract remains the gold standard for diagnostic evaluation; nevertheless, ancillary/biomarker studies are increasingly utilized in daily practice to assist in the subclassification of gynecologic lesions and tumors. The most frequently utilized "biomarker" technique is immunohistochemistry; however, in situ hybridization (chromogenic and fluorescence), chromosomal evaluation, and molecular analysis can also be utilized to aid in diagnosis. This review focuses on the use of immunohistochemistry in the Mullerian tract, and discusses common antibody panels, sensitivity and specificity of specific antibodies, and points out potential diagnostic pitfalls when using such antibodies.

Ectopic Non-gestational Pure Choriocarcinoma of the Urinary Bladder in a Young Nulliparous Female: A Diagnostic Challenge

Choriocarcinoma can occur at ectopic extragenital locations such as lungs, mediastinum, retroperitoneum, and even in the brain (nongestational choriocarcinoma). Choriocarcinoma arising in the urinary bladder is extremely uncommon with only a few cases reported worldwide. It is important to recognize and give comprehensive diagnosis of this entity, as it has poorer prognosis as compared to the conventional gestational choriocarcinoma and requires stepped-up chemotherapy. Here, we present such a case in a 19-year-old girl and the diagnostic conundrum associated with it.

GATA3 Expression in Common Gynecologic Carcinomas: A Potential Pitfall

GATA binding protein 3 (GATA3) immunohistochemistry is primarily used as a marker of breast and urothelial differentiation, particularly in metastatic settings. In the gynecologic tract it also serves a robust marker for mesonephric and trophoblastic tumors. However, expression has also been described in more common malignancies of gynecologic tract including ovarian, endometrial, and cervical carcinomas. Data on the distribution of GATA3 expression in gynecologic malignancies is somewhat limited, particularly across different histologic subtypes of ovarian, endometrial, and cervical carcinomas. To assess the rates of GATA3 expression among common gynecologic cancers of various histologic types, 100 ovarian carcinomas, 64 endometrial carcinomas/atypical hyperplasias, 16 cervical squamous cell carcinomas (SCCs), and 14 endocervical adenocarcinomas were evaluated by immunohistochemistry for GATA3 positivity. Eight percent of endometrial carcinomas expressed GATA3, including 2 serous carcinomas, 1 carcinosarcoma, and 1 case of atypical hyperplasia. Six percent of ovarian carcinomas were GATA3-positive including 2 clear cell carcinomas, 2 mucinous adenocarcinomas, and 2 high-grade serous carcinomas. Thirty-eight percent of cervical SCCs showed weak to moderate staining in up to 50% of tumor cells. All endocervical adenocarcinomas were entirely negative for GATA3. In summary, GATA3 shows focal weak to moderate expression in a subset of endometrial and ovarian carcinomas. In contrast, usual-type endocervical adenocarcinomas are typically negative for GATA3, which can be helpful in differentiating them from mesonephric proliferations or carcinomas. A larger proportion of cervical SCCs express GATA3, therefore caution should be exercised when using this stain in the setting of a lower genitourinary carcinomas.

Development of the human placenta

The placenta is essential for normal in utero development in mammals. In humans, defective placental formation underpins common pregnancy disorders such as pre-eclampsia and fetal growth restriction. The great variation in placental types across mammals means that animal models have been of limited use in understanding human placental development. However, new tools for studying human placental development, including 3D organoids, stem cell culture systems and single cell RNA sequencing, have brought new insights into this field. Here, we review the morphological, molecular and functional aspects of human placental formation, with a focus on the defining cell of the placenta - the trophoblast.

A Comparison of GATA3, TTF1, CD10, and Calretinin in Identifying Mesonephric and Mesonephric-like Carcinomas of the Gynecologic Tract

Mesonephric carcinomas of the gynecologic tract are neoplasms that are often under-recognized due to their varied morphologic appearances. Recently, GATA3 and TTF1 have been reported to be useful immunohistochemical markers for distinguishing mesonephric carcinomas from its morphologic mimics. Herein, we compared the performance of GATA3 and TTF1 to the traditional markers used for mesonephric carcinomas, CD10 and calretinin. We studied 694 cases: 8 mesonephric carcinomas (7 cervical [includes 3 mesonephric carcinosarcomas], 1 vaginal), 5 mesonephric-like carcinomas (4 uterine corpus, 1 ovarian), 585 endometrial adenocarcinomas, and 96 cervical adenocarcinomas. Mesonephric-like carcinomas were defined as tumors exhibiting the classic morphologic features of mesonephric carcinoma, but occurring outside of the cervix and without convincing mesonephric remnants. GATA3 had the highest sensitivity and specificity (91% and 94%) compared with TTF1 (45% and 99%), CD10 (73% and 83%), and calretinin (36% and 89%). GATA3, however, also stained a substantial number of uterine carcinosarcomas (23/113, 20%). TTF1 was positive in 5/5 (100%) mesonephric-like carcinomas and only 1/8 (13%) mesonephric carcinomas. In 4/6 (67%) TTF1 positive cases, GATA3 exhibited an inverse staining pattern with TTF1. In summary, GATA3 was the best overall marker for mesonephric and mesonephric-like carcinomas, but cannot be used to distinguish mesonephric carcinosarcomas from Müllerian carcinosarcomas. The inverse staining pattern between GATA3 and TTF1, suggests that TTF1 may be useful when GATA3 is negative in small biopsies where mesonephric or mesonephric-like carcinoma is suspected. The greater TTF1 positivity in mesonephric-like carcinomas suggests they may be biologically different from prototypical mesonephric carcinomas.

A combination of GATA3 and SOX10 is useful for the diagnosis of metastatic triple-negative breast cancer

In metastatic breast cancer (MBC), it can be difficult to establish the origin if the primary tumor is triple negative or if there is a loss of biomarker expression. SOX10 expression has been reported in primary triple-negative breast cancer but is poorly studied in metastatic lesions. In this study, the diagnostic utility of a panel of SOX10, GATA3, and androgen receptor (AR) in MBC negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 was evaluated and compared with the expression of these markers in the matched primary breast cancer. In a series of 57 triple-negative MBCs, 82% were positive for GATA3, 58% for SOX10, and 25% for AR. Nearly all MBCs (95%) were positive for either GATA3 or SOX10, with 46% dual positive and 5% of cases negative for both markers. Most GATA3-negative MBC cases were SOX10 positive (70%). AR expression was only seen in GATA3-positive MBC (25%) and was significantly more frequent in SOX10-negative MBC (48%) versus SOX10-positive MBC (9%; P = .001). Concordance for GATA3, SOX10, and AR between the primary and metastasis was 89%, 88%, and 80%, respectively. Although GATA3 is a more sensitive lineage marker than SOX10 in MBC, SOX10 is a useful adjunct because it is positive in most GATA3-negative breast metastases. Using both GATA3 and SOX10 is recommended for confirming breast as the site of origin in metastases that lack estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 expression, whereas the addition of AR is not helpful.

GATA3 as a master regulator and therapeutic target in ovarian high-grade serous carcinoma stem cells

Ovarian high-grade serous carcinoma (HGSC) is the most lethal gynecological malignancy. Prevailing evidences suggest that drug resistance and recurrence of ovarian HGSC are caused by the presence of cancer stem cells. Therefore, targeting cancer stems is appealing, however, all attempts to date, have failed. To circumvent this limit, we analyzed differential transcriptomes at early differentiation of ovarian HGSC stem cells and identified the developmental transcription factor GATA3 as highly expressed in stem, compared to progenitor cells. GATA3 expression associates with poor prognosis of ovarian HGSC patients, and was found to recruit the histone H3, lysine 27 (H3K27) demethylase, UTX, activate stemness markers, and promote stem-like phenotypes in ovarian HGSC cell lines. Targeting UTX by its inhibitor, GSKJ4, impeded GATA3-driven stemness phenotypes, and enhanced apoptosis of GATA3-expressing cancer cells. Combinations of gemcitabine or paclitaxel with GSKJ4, resulted in a synergistic cytotoxic effect. Our findings provide evidence for a new role for GATA3 in ovarian HGSC stemness, and demonstrate that GATA3 may serve as a biomarker for precision epigenetic therapy in the future.

Use of GATA3 and TWIST1 Immunofluorescence Staining to Assess In Vitro Syncytial Fusion Index

In human placenta, the multinucleated syncytiotrophoblast (ST) allows all the exchanges between the maternal and fetal circulation and is also the site of placental hormonal functions. Absence or disturbances of ST formation are associated with a defect or pathologies of pregnancy such as preeclampsia (PE) and intrauterine growth retardation (IUGR). All along pregnancy, the ST is regenerated by fusion of underlying mononucleated villous cytotrophoblasts (VCT). The protocol described here provides details on how GATA3 or TWIST1 immunostaining and analysis can be used to easily assess the in vitro differentiation of human placental cytotrophoblast.

Immunohistochemistry in Gynecologic Pathology: An Example-Based Practical Update

CONTEXT

- Immunohistochemical stains are routinely applied in the pathology diagnostic workup of gynecologic lesions. The rapidly expanding repertoire of available markers helps in refining the diagnostic criteria for each disease entity; however, limitations and pitfalls exist.

OBJECTIVE

- To provide a practical, relevant update on the use of immunohistochemistry for commonly encountered differential diagnoses in gynecologic pathology.

DATA SOURCES

- Literature review and authors' diagnostic experience.

CONCLUSIONS

- Immunohistochemistry is a helpful adjunct tool in gynecologic pathology. Although the primary application is in the diagnostic workup, novel prognostic and predictive markers, and immunostains to screen for genetic cancer syndromes, have also been recently introduced in the field.

The World Health Organization 2016 classification of testicular germ cell tumours: a review and update from the International Society of Urological Pathology Testis Consultation Panel

Since the last World Health Organization (WHO) classification scheme for tumours of the urinary tract and male genital organs, there have been a number of advances in the understanding, classification, immunohistochemistry and genetics of testicular germ cell tumours. The updated 2016 draft classification was discussed at an International Society of Urological Pathology Consultation on Testicular and Penile Cancer. This review addresses the main updates to germ cell tumour classification. Major changes include a pathogenetically derived classification using germ cell neoplasia in situ (GCNIS) as a new name for the precursor lesion, and the distinction of prepubertal tumours (non-GCNIS-derived) from postpubertal-type tumours (GCNIS-derived), acknowledging the existence of rare benign prepubertal-type teratomas in the postpubertal testis. Spermatocytic tumour is adopted as a replacement for spermatocytic seminoma, to avoid potential confusion with the unrelated usual seminoma. The spectrum of trophoblastic tumours arising in the setting of testicular germ cell tumour continues to expand, to include epithelioid and placental site trophoblastic tumours analogous to those of the gynaecological tract. Currently, reporting of anaplasia (seminoma or spermatocytic tumour) or immaturity (teratoma) is not required, as these do not have demonstrable prognostic importance. In contrast, overgrowth of a teratomatous component (somatic-type malignancy) and sarcomatous change in spermatocytic tumour indicate more aggressive behaviour, and should be reported.

Markers of metastatic carcinoma of breast origin

This review summarizes the three major breast-associated markers that can be of assistance in evaluating metastatic carcinomas for which a breast primary diagnosis is entertained. These markers include gross cystic disease fluid protein-15 (GCDFP-15), mammaglobin, and GATA3. The first two are cytoplasmic markers that show comparable sensitivities for breast cancer, although relatively few of the published studies have employed the same antibodies against the target molecule, making direct comparisons challenging. GATA3 is a nuclear transcription factor that shows superior sensitivity to GCDFP-15 and mammaglobin. However, the specificity of GATA3 can pose challenges, inasmuch as carcinomas of the bladder and other sites can show significant levels of positivity. Determination of the optimal panel of antibodies employed in a given clinical setting will thus depend on the non-breast tumours included in the differential diagnosis.

GATA3 expression in clinically useful groups of breast carcinoma: a comparison with GCDFP15 and mammaglobin for identifying paired primary and metastatic tumors

GATA3 has been recognized as the novel marker for identifying primary and metastatic breast carcinomas, consistently showing that GATA3 was significantly more sensitive than traditional markers gross cystic disease fluid protein 15 (GCDFP15) and mammaglobin (MGB). However, clinically useful groups of breast carcinomas status were not identified, which were determining appropriate treatment strategy, affecting the prognosis. In this study, we undertook a comparative study of the marker GATA3 and GCDFP15 and MGB in clinically useful groups of paired primary and metastatic breast cancer. We retrieved 64 cases of matched primary and metastatic breast cancer from the surgical pathology archive at our institution. According to the emerging 2015 St. Gallen Consensus, the clinically useful groups were divided into ER and/or PR (+), HER2 (-), abbreviated as A; ER and/or PR (+), HER2 (+), abbreviated as B; ER and PR (-), HER2 (+), abbreviated as C; ER, PR and HER2 (-), abbreviated as D; each group contained 16 cases (n=16). Tissue microarrays were created, with three 1-mm punch specimens from each case. The tissue microarrays were cut at 4-μm thickness and stained with monoclonal antibodies to GATA3, GCDFP15, and MGB. Staining intensity (0-3+) and extent (0%-100%) were scored with an H-score calculated (range, 0-300). Sensitivities by varying H-score cutoffs (any; ≥50; ≥150) for a positive result in the clinically useful groups of matched primary or metastatic breast cancer among GATA3, GCDFP15, and MGB. GATA3 was significantly more sensitive than GCDFP15 and MGB A and B groups (P<.05) rather than C and D groups (P>.05). However, GATA3 in conjunction with GCDFP15 and MGB detection could improve the sensitivity of C group (P<.05) rather than D group (P>.05). Significantly, good coincidence was observed between primary and metastatic tumor GATA3 expression (κ value = 0.826 >0.75) as compared with the coincidence of GCDFP15 (κ value =0.492 <0.75) and MGB (κ value =0.593 <0.75) (both P<.05). In conclusion, GATA3 expression did not show the same sensitivity for the clinically useful groups of breast cancer. GATA3 expression is positively correlated with ER-positive, PR-positive, and HER2-positive carcinomas. In addition, the matched primary and metastatic tumor expression of GATA3 shows good coincidence. We propose the careful selection of GATA3 for identifying hormone receptor negativity of breast cancer, especially in the case of triple-negative breast cancer.

Tumors of the Testis: Morphologic Features and Molecular Alterations

This article reviews the most frequently encountered tumor of the testis; pure and mixed malignant testicular germ cell tumors (TGCT), with emphasis on adult (postpubertal) TGCTs and their differential diagnoses. We additionally review TGCT in the postchemotherapy setting, and findings to be integrated into the surgical pathology report, including staging of testicular tumors and other problematic issues. The clinical features, gross pathologic findings, key histologic features, common differential diagnoses, the use of immunohistochemistry, and molecular alterations in TGCTs are discussed.

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.