Metastatic trophoblastic disease after an initial diagnosis of partial hydatidiform mole: genotyping and chromosome in situ hybridization analysis

Morphology combined with HER2 D-DISH ploidy analysis to diagnose partial hydatidiform mole: an evaluation audit using molecular genotyping

AIMS

A hydatidiform mole (HM) is classified as complete (CHM) or partial (PHM) based on its morphology and genomic composition. Ancillary techniques are often required to confirm a morphologically suspected PHM diagnosis. This study sought to evaluate the clinical accuracy of PHM diagnosis using morphological assessment supported by HER2 dual-colour dual-hapten in situ hybridisation (D-DISH) ploidy determination.

METHODS

Over a 2-year period, our unit examined 1265 products of conception (POCs) from which 103 atypical POCs were diagnosed as PHM or non-molar conceptuses with the assistance of HER2 D-DISH ploidy analysis. We retrospectively audited a sample of 40 of these atypical POCs using short tandem repeat genotyping. DNA extracted from formalin-fixed paraffin-embedded tissue was genotyped using 24 polymorphic loci. Parental alleles in placental villi were identified by comparison to those in maternal decidua. To identify triploid PHM cases, we sought three alleles of equal peak height or two alleles with one allele peak twice the height of the other at each locus.

RESULTS

Thirty-six of the 40 cases (19 PHM and 17 non-molar) were successfully genotyped and demonstrated complete concordance with the original diagnosis. All PHMs were diandric triploid of dispermic origin. In two non-molar diploid cases, we identified suspected trisomies (13 and 18), which potentially explains the pregnancy loss in these cases.

CONCLUSIONS

This study validates the use of HER2 D-DISH ploidy analysis to support the diagnosis of a morphologically suspected PHM in our practice.

Novel scoring system provides high separation of diploidy and triploidy to aid partial hydatidiform mole diagnosis: an adaption of HER2 D-DISH for ploidy analysis

AIMS

Diagnosis of hydatidiform mole or molar pregnancy based on morphology alone can be challenging, particularly in early gestation, necessitating the use of ancillary techniques for accurate diagnosis. We sought to adapt the VENTANA HER2 dual-colour dual-hapten in-situ hybridisation (D-DISH) assay by using the internal chromosome 17 enumeration probe to determine ploidy status.

METHODS

We selected 25 products of conception, consisting of molar and non-molar cases, to validate the HER2 D-DISH assay. These cases had prior morphological assessment by a perinatal pathologist and ploidy analysis using molecular cytogenetics. Three independent observers, blinded to the original histopathological and genetic diagnosis, scored 10 representative areas on each slide. Interobserver variability was assessed by comparing the total scores of each observer using analysis of variance (ANOVA) and the kappa statistic.

RESULTS

Our ploidy scoring system accurately determined the correct number of diploid and triploid conceptuses, demonstrating complete concordance with pre-existing ploidy status and the initial diagnosis. Interobserver agreement between three independent scorers was robust: ANOVA (p=0.36) and kappa statistic (0.812, p<0.001). We achieved clear separation of average nuclear signals for diploid and triploid conceptuses, which was statistically significant (p<0.05). Employing our innovative scoring system, known as the 'rule of 5', we established ploidy decision thresholds for all 25 cases.

CONCLUSIONS

Our modified HER2 D-DISH ploidy assay simplifies the process of ploidy determination and improves the accuracy of morphological diagnosis of molar pregnancy. The HER2 D-DISH assay was selected for ploidy analysis due to the widespread availability of in-situ hybridisation in pathology laboratories.

When to Consult a Geneticist Specialising in Gestational Trophoblastic Disease

BACKGROUND

Gestational trophoblastic disease comprises hydatidiform moles and a rare group of malignancies that derive from trophoblasts. Although there are typical morphological features that may distinguish hydatidiform moles from non-molar products of conception, such features are not always present, especially at early stages of pregnancy. Furthermore, mosaic/chimeric pregnancies and twin pregnancies make pathological diagnosis challenging while trophoblastic tumours can also pose diagnostic problems in terms of their gestational or non-gestational origin.

OBJECTIVES

The aim of this study was to show that ancillary genetic testing can be used to aid diagnosis and clinical management of GTD.

METHODS

Each author identified cases where genetic testing, including short tandem repeat (STR) genotyping, ploidy analysis, next-generation sequencing, and immunostaining for p57, the product of the imprinted gene CDKN1C, facilitated accurate diagnosis and improved patient management. Representative cases were chosen to illustrate the value of ancillary genetic testing in different scenarios.

OUTCOME

Genetic analysis of placental tissue can aid in determining the risk of developing gestational trophoblastic neoplasia, facilitating discrimination between low risk triploid (partial) and high risk androgenetic (complete) moles, discriminating between a hydatidiform mole twinned with a normal conceptus and a triploid conception and identification of androgenetic/biparental diploid mosaicism/chimerism. STR genotyping of placental tissue and targeted gene sequencing of patients can identify women with an inherited predisposition to recurrent molar pregnancies. Genotyping can distinguish gestational from non-gestational trophoblastic tumours using tissue or circulating tumour DNA and can also identify the causative pregnancy which is the key prognostic factor for placental site and epithelioid trophoblastic tumours.

CONCLUSIONS AND OUTLOOK

STR genotyping and p57 immunostaining have been invaluable to the management of gestational trophoblastic disease in many situations. The use of next-generation sequencing and of liquid biopsies is opening up new pathways for GTD diagnostics. Development of these techniques has the potential to identify novel biomarkers of GTD and further refine diagnosis.

Short tandem repeat analysis to identify the causative pregnancy of high-risk gestational trophoblastic neoplasia: Molar versus nonmolar pregnancy and its relation to the outcome

INTRODUCTION

Gestational trophoblastic neoplasia (GTN) include a group of malignant neoplasms that originate from the trophoblasts of placental tissue in molar or nonmolar pregnancy. Currently, it is unclear whether the prognosis of high-risk GTN or gestational choriocarcinoma succeeding molar pregnancy or that following a nonmolar one is better. Comparison of the genetic short tandem repeat (STR) patterns of the DNA extracted from the tumor, patient, and her partner allows the genetic origins of the choriocarcinoma to be distinguished - whether it is gestational or non-gestational and whether it is derived from a molar or nonmolar pregnancy in the event it is gestational. This study aimed to investigate the causative pregnancy of patients with high-risk GTN, especially those with poor outcomes, and assess the impact of the causative pregnancy on patient outcome.

METHODS

We evaluated 24 patients who were diagnosed with high-risk GTN between January 2000 and October 2019, including 15 cases of pathologically proven gestational choriocarcinomas and the causative pregnancy was investigated by STR analysis in which tumor DNA could be extracted.

RESULTS

In high-risk GTN without history of anteceding molar pregnancies, nonmolar pregnancy was the causative pregnancy, which was confirmed in three cases. Molar pregnancy appeared be the causative pregnancy of high-risk GTN in patients with a history of antecedent molar pregnancies either with or without interruption by subsequent nonmolar pregnancies prior to developing high-risk GTN. High-risk GTN in most of the evaluated deceased cases (three of four) was due to nonmolar pregnancy, while all but one case with molar pregnancy as the causative pregnancy survived.

DISCUSSION

STR analysis can distinguish the causative pregnancy of high-risk GTN, and nonmolar pregnancy as the causative pregnancy might have negative effects on the outcome of the disease.

Maternal complications in molecularly confirmed diandric and digynic triploid pregnancies: single institution experience and literature review

Objectives

Assessment of the maternal complications in molecularly confirmed diandric and digynic triploid pregnancies.

Methods

Sonographic features, biochemical results, and clinical presentation were analyzed. Beta-hCG level was controlled after diandric triploidy.

Results

The study included nine diandric and twelve digynic triploid pregnancies at the mean gestational age at diagnosis of 14.9 and 18.0 weeks, respectively (p = 0.0391). Mean value of total-hCG was 979 703.6 U/ml in diandric cases and 5 455.4 U/ml in digynic ones (p < 0.000). Maternal complications occurred in 88.9% of diandric triploid pregnancies, including: thecalutein cysts (44.4%), hyperemesis gravidarum (44.4%), symptomatic hyperthyreosis (33.3%), early onset gestational hypertension (22.2%) and vaginal bleeding (11.1%). No case of proteinuria, preeclampsia or HELLP syndrome was observed. Only maternal complication observed in digynic triploidy was vaginal bleeding (50.0%). The mean time of beta-hCG normalization after diandric triploid pregnancies was 84 days (range 11–142 days). No case of gestational trophoblastic neoplasia (GTN) was observed.

Conclusions

Maternal complications (except for vaginal bleeding) are associated with diandric triploidy. The relatively low incidence of hypertensive maternal complications and their less severe course in our cohort may be attributed to the earlier prenatal diagnosis. The frequency of GTN after diandric triploidy may be lower than previously reported.

Hydatidiform Moles: Ancillary Techniques to Refine Diagnosis

Context.—

Distinction of hydatidiform moles from nonmolar specimens and subclassification of hydatidiform moles as complete hydatidiform mole versus partial hydatidiform mole are important for clinical practice and investigational studies. Risk of persistent gestational trophoblastic disease and clinical management differ for these entities. Diagnosis based on morphology is subject to interobserver variability and remains problematic, even for experienced gynecologic pathologists.

Objectives.—

To explain how ancillary techniques target the unique genetic features of hydatidiform moles to establish diagnostic truth, highlight the issue of diagnostic reproducibility and importance of diagnostic accuracy, and illustrate use of p57 immunohistochemistry and polymerase chain reaction–based DNA genotyping for diagnosis.

Data Sources.—

Sources are the author's 10-year experience using ancillary techniques for the evaluation of potentially molar specimens in a large gynecologic pathology practice and the literature.

Conclusions.—

The unique genetics of complete hydatidiform moles (purely androgenetic), partial hydatidiform moles (diandric triploid), and nonmolar specimens (biparental, with allelic balance) allow for certain techniques, including immunohistochemical analysis of p57 expression (a paternally imprinted, maternally expressed gene) and genotyping, to refine diagnoses of hydatidiform moles. Although p57 immunostaining alone can identify complete hydatidiform moles, which lack p57 expression because of a lack of maternal DNA, this analysis does not distinguish partial hydatidiform moles from nonmolar specimens because both express p57 because of the presence of maternal DNA. Genotyping, which compares villous and decidual DNA patterns to determine the parental source and ratios of polymorphic alleles, distinguishes purely androgenetic complete hydatidiform moles from diandric triploid partial hydatidiform moles, and both of these from biparental nonmolar specimens. An algorithmic approach to diagnosis using these techniques is advocated.

Gestational Trophoblastic Neoplasia From Genetically Confirmed Hydatidiform Moles: Prospective Observational Cohort Study

Objective

The aim of this study was to evaluate the incidence and risk factors of gestational trophoblastic neoplasia (GTN) from hydatidiform moles (HMs) cytogenetically diagnosed in a prospective cohort setting.

Methods

The prospective observational cohort study included cases of cytogenetically defined molar pregnancies, which were diagnosed by a multiplex short tandem repeat polymorphism analysis. Cases were classified as androgenetic complete HMs (CHMs), diandric monogynic triploid partial HMs (PHMs), or biparental abortion. Gestational trophoblastic neoplasia was diagnosed according to the International Federation of Gynecology and Obstetrics 2000 criteria. Incidences for each category, that is, CHM, PHMs, and biparental abortion, were calculated. Clinical variables (age, partner age, gravidity, parity, height, weight, BMI, and gestational age) and laboratory data (serum human chorionic gonadotropin [hCG], white blood cell count, hemoglobin, and platelet count) were compared between spontaneous remission cases and GTN cases in androgenetic CHMs.

Results

Among 401 cases, 380 were classified as follows: 232 androgenetic CHMs, 60 diandric monogynic PHMs, and 88 biparental abortions. A total of 35 cases (15.1%) of CHMs, but only 1 case of PHM (1.7%) and no biparental abortions, exhibited progression to GTN. The hCG value before evacuation was significantly higher in GTN cases than in spontaneous remission cases (P = 0.001, Kruskal-Wallis test). Patient age was also significantly higher in GTN cases than in spontaneous remission cases (P = 0.002, Student t test).

Conclusions

Under the cohort cytogenetic diagnosis setting, the traditional risk factors for GTN after molar pregnancy, hCG value before evacuation and age, were confirmed in androgenetic CHMs. The risk of GTN was lower for PHMs than for CHMs. However, 1 patient with cytogenetic PHMs developed into GTN.

A Molar Pregnancy within the Fallopian Tube

Background. Discussion of the incidence of molar pregnancy and ectopic pregnancy. Role of salpingostomy and special considerations for postoperative care. Case. The patient is a 29-year-old G7P4 who presented with vaginal bleeding in the first trimester and was initially thought to have a spontaneous abortion. Ultrasound was performed due to ongoing symptoms and an adnexal mass was noted. She underwent uncomplicated salpingostomy and was later found to have a partial molar ectopic pregnancy. Conclusion. This case illustrates the rare occurrence of a molar ectopic pregnancy. There was no indication of molar pregnancy preoperatively and this case highlights the importance of submitting and reviewing pathological specimens.

Utilization of Chromogenic In Situ Hybridization to Assess Ploidy in the Diagnosis of Hydatidiform Mole

OBJECTIVES

Ploidy assessment is often required for the diagnosis of partial molar pregnancy. While fluorescence in situ hybridization has been shown to be effective, it is not available in many laboratories. We validated chromogenic in situ hybridization (CISH) for this purpose.

METHODS

CISH using probes to chromosomes 17 and 10 was performed on 20 POC cases with known cytogenetics to establish a reference percentage. This was then used to classify a randomized set of abnormal and normal cases.

RESULTS

An abnormal CISH cutoff of greater than 7% was established. All abnormal cases (six triploid and three tetraploid), 11 "normal" (46, XX or XY or undetectable abnormalities), and one trisomy 10 were all correctly classified by the assay.

CONCLUSIONS

CISH is a useful ancillary technique for the diagnosis of molar pregnancy. Its greater accessibility and ability to score even rare placental tissue in a background of maternal tissue offer advantages over other methods.

FBI-1 Is Overexpressed in Gestational Trophoblastic Disease and Promotes Tumor Growth and Cell Aggressiveness of Choriocarcinoma via PI3K/Akt Signaling

Human placental trophoblasts can be considered pseudomalignant, with tightly controlled proliferation, apoptosis, and invasiveness. Gestational trophoblastic disease (GTD) represents a family of heterogeneous trophoblastic lesions with aberrant apoptotic and proliferative activities and dysregulation of cell signaling pathways. We characterize the oncogenic effects of factor that binds to the inducer of short transcripts of HIV-1 [FBI-1, alias POZ and Krüppel erythroid myeloid ontogenic factor (POKEMON)/ZBTB7A] in GTD and its role in promoting cell aggressiveness in vitro and tumor growth in vivo. IHC studies showed increased nuclear expression of FBI-1, including hydatidiform moles, choriocarcinoma (CCA), and placental site trophoblastic tumor, in GTD. In JAR and JEG-3 CCA cells, ectopic FBI-1 expression opposed apoptosis through repression of proapoptotic genes (eg, BAK1, FAS, and CASP8). FBI-1 overexpression also promoted Akt activation, as indicated by Akt-pS473 phosphorylation. FBI-1 overexpression promoted mobility and invasiveness of JEG-3 and JAR, but not in the presence of the phosphoinositide 3-kinase inhibitor LY294002. These findings suggest that FBI-1 could promote cell migration and invasion via phosphoinositide 3-kinase/Akt signaling. In vivo, nude mice injected with CCA cells with stable FBI-1 knockdown demonstrated reduced tumor growth compared with that in control groups. These findings suggest that FBI-1 is clinically associated with the progression of, and may be a therapeutic target in, GTD, owing to its diverse oncogenic effects on dysregulated trophoblasts.

Triploidy--Observations in 154 Diandric Cases

Hydatidiform moles (HMs) are abnormal human pregnancies with vesicular chorionic villi, imposing two clinical challenges; miscarriage and a risk of gestational trophoblastic neoplasia (GTN). The parental type of most HMs are either diandric diploid (PP) or diandric triploid (PPM). We consecutively collected 154 triploid or near-triploid samples from conceptuses with vesicular chorionic villi. We used analysis of DNA markers and/or methylation sensitive-MLPA and collected data from registries and patients records. We performed whole genome SNP analysis of one case of twinning (PP+PM).In all 154 triploids or near-triploids we found two different paternal contributions to the genome (P1P2M). The ratios between the sex chromosomal constitutions XXX, XXY, and XYY were 5.7: 6.9: 1.0. No cases of GTN were observed. Our results corroborate that all triploid human conceptuses with vesicular chorionic villi have the parental type P1P2M. The sex chromosomal ratios suggest approximately equal frequencies of meiosis I and meiosis II errors with selection against the XYY conceptuses or a combination of dispermy, non-disjunction in meiosis I and meiosis II and selection against XYY conceptuses. Although single cases of GTN after a triploid HM have been reported, the results of this study combined with data from previous prospective studies estimate the risk of GTN after a triploid mole to 0% (95% CI: 0–1,4%).

Characteristics of hydatidiform moles: analysis of a prospective series with p57 immunohistochemistry and molecular genotyping

Immunohistochemical analysis of cyclin-dependent kinase inhibitor 1C (CDKN1C, p57, Kip2) expression and molecular genotyping accurately classify hydatidiform moles into complete and partial types and distinguish these from non-molar specimens. Characteristics of a prospective series of all potentially molar specimens encountered in a large gynecologic pathology practice are summarized. Initially, all specimens were subjected to both analyses; this was later modified to triage cases for genotyping based on p57 results: p57-negative cases diagnosed as complete hydatidiform moles without genotyping; all p57-positive cases genotyped. Of the 678 cases, 645 were definitively classified as complete hydatidiform mole (201), partial hydatidiform mole (158), non-molar (272), and androgenetic/biparental mosaic (14); 33 were unsatisfactory, complex, or problematic. Of the 201 complete hydatidiform moles, 104 were p57-negative androgenetic and an additional 95 were p57-negative (no genotyping), 1 was p57-positive (retained maternal chromosome 11) androgenetic, and 1 was p57-non-reactive androgenetic; 90 (85%) of the 106 genotyped complete hydatidiform moles were monospermic and 16 were dispermic. Of the 158 partial hydatidiform moles, 155 were diandric triploid, with 154 p57-positive, 1 p57-negative (loss of maternal chromosome 11), and 1 p57-non-reactive; 3 were triandric tetraploid, with 2 p57-positive and 1 p57-negative (loss of maternal chromosome 11). Of 155 diandric triploid partial hydatidiform moles, 153 (99%) were dispermic and 2 were monospermic. Of the 272 non-molar specimens, 259 were p57-positive biparental diploid, 5 were p57-positive digynic triploid, 2 were p57-negative biparental diploid (no morphological features of biparental hydatidiform mole), and 6 were p57-non-reactive biparental diploid. Of the 14 androgenetic/biparental mosaics with discordant p57 expression, 6 were uniformly mosaic and 8 had a p57-negative androgenetic molar component. p57 expression is highly correlated with genotyping, serves as a reliable marker for diagnosis of complete hydatidiform moles, and identifies androgenetic cell lines in mosaic conceptions. Cases with aberrant and discordant p57 expression can be correctly classified by genotyping.

Downregulation of ASPP2 in choriocarcinoma contributes to increased migratory potential through Src signaling pathway activation

Gestational choriocarcinoma is a malignant tumor derived from placental trophoblast and the most aggressive member of gestational trophoblastic disease (GTD). Apoptosis-stimulating protein of p53-2 (ASPP2) is a member of ASPP family that transactivates p53 and thereby functions as a tumor suppressor. In this study, the expression profile of ASPP2 in choriocarcinoma was examined in comparison with normal placentas and hydatidiform moles, the latter being a type of GTD that carries malignant potential. Downregulation of ASPP2 messenger RNA and protein was demonstrated in choriocarcinoma by quantitative PCR and immunohistochemistry. ASPP2-transfected choriocarcinoma cells (JEG-3 and JAR) showed an increase in apoptosis and a decrease in cell migration as detected by TdT-mediated dUTP nick end labeling and wound healing assays, respectively, illustrating the complex action of ASPP2 on cell functions other than programmed cell death. Activated Src is known to be important in tumor progression. Transfection of ASPP2 but not ASPP1, another tumor-suppressive ASPP, was found to be related to subsequent decreased Src-pY416 phosphorylation, suggesting an inactivating effect of ASPP2 on Src. Moreover, this ASPP2-mediated inactivation of Src could be abolished by RNA interference with C-terminal Src kinase (Csk), a kinase that can inhibit Src activation. Our findings suggested that the ability of ASPP2 to attenuate Src activation was specific to ASPP2 in a Csk-dependent manner. Taken together, we demonstrated a loss of tumor-suppressive ASPP2 in choriocarcinoma with effects on cell migration and apoptosis. We also unveiled a possible mechanistic link between ASPP2 and Csk/Src signaling pathway, implicating the multiple cellular functions of ASPP2.

Diagnostic reproducibility of hydatidiform moles: ancillary techniques (p57 immunohistochemistry and molecular genotyping) improve morphologic diagnosis for both recently trained and experienced gynecologic pathologists

Distinction of hydatidiform moles from nonmolar specimens (NMs) and subclassification of hydatidiform moles as complete hydatidiform mole (CHM) and partial hydatidiform mole (PHM) are important for clinical practice and investigational studies; however, diagnosis based solely on morphology is affected by interobserver variability. Molecular genotyping can distinguish these entities by discerning androgenetic diploidy, diandric triploidy, and biparental diploidy to diagnose CHMs, PHMs, and NMs, respectively. Eighty genotyped cases (27 CHMs, 27 PHMs, 26 NMs) were selected from a series of 200 potentially molar specimens previously diagnosed using p57 immunohistochemistry and genotyping. Cases were classified by 6 pathologists (3 faculty level gynecologic pathologists and 3 fellows) on the basis of morphology, masked to p57 immunostaining and genotyping results, into 1 of 3 categories (CHM, PHM, or NM) during 2 diagnostic rounds; a third round incorporating p57 immunostaining results was also conducted. Consensus diagnoses (those rendered by 2 of 3 pathologists in each group) were also determined. Performance of experienced gynecologic pathologists versus fellow pathologists was compared, using genotyping results as the gold standard. Correct classification of CHMs ranged from 59% to 100%; there were no statistically significant differences in performance of faculty versus fellows in any round (P-values of 0.13, 0.67, and 0.54 for rounds 1 to 3, respectively). Correct classification of PHMs ranged from 26% to 93%, with statistically significantly better performance of faculty versus fellows in each round (P-values of 0.04, <0.01, and <0.01 for rounds 1 to 3, respectively). Correct classification of NMs ranged from 31% to 92%, with statistically significantly better performance of faculty only in round 2 (P-values of 1.0, <0.01, and 0.61 for rounds 1 to 3, respectively). Correct classification of all cases combined ranged from 51% to 75% by morphology and 70% to 80% with p57, with statistically significantly better performance of faculty only in round 2 (P-values of 0.69, <0.01, and 0.15 for rounds 1 to 3, respectively). p57 immunostaining significantly improved recognition of CHMs (P<0.01) and had high reproducibility (κ=0.93 to 0.96) but had no impact on distinction of PHMs and NMs. Genotyping provides a definitive diagnosis for the ∼25% to 50% of cases that are misclassified by morphology, especially those that are also unresolved by p57 immunostaining.

Diagnostic reproducibility of hydatidiform moles: ancillary techniques (p57 immunohistochemistry and molecular genotyping) improve morphologic diagnosis

Distinction of hydatidiform moles (HMs) from nonmolar specimens (NMs) and subclassification of HMs as complete hydatidiform moles (CHMs) and partial hydatidiform moles (PHMs) are important for clinical practice and investigational studies; yet, diagnosis based solely on morphology is affected by interobserver variability. Molecular genotyping can distinguish these entities by discerning androgenetic diploidy, diandric triploidy, and biparental diploidy to diagnose CHMs, PHMs, and NMs, respectively. Eighty genotyped cases (27 CHMs, 27 PHMs, and 26 NMs) were selected from a series of 200 potentially molar specimens previously diagnosed using p57 immunostaining and genotyping. Cases were classified by 3 gynecologic pathologists on the basis of H&E slides (masked to p57 immunostaining and genotyping results) into 1 of 3 categories (CHM, PHM, or NM) during 2 diagnostic rounds; a third round incorporating p57 immunostaining results was also conducted. Consensus diagnoses (those rendered by 2 of 3 pathologists) were determined. Genotyping results were used as the gold standard for assessing diagnostic performance. Sensitivity of a diagnosis of CHM ranged from 59% to 100% for individual pathologists and from 70% to 81% by consensus; specificity ranged from 91% to 96% for individuals and from 94% to 98% by consensus. Sensitivity of a diagnosis of PHM ranged from 56% to 93% for individual pathologists and from 70% to 78% by consensus; specificity ranged from 58% to 92% for individuals and from 74% to 85% by consensus. The percentage of correct classification of all cases by morphology ranged from 55% to 75% for individual pathologists and from 70% to 75% by consensus. The κ values for interobserver agreement ranged from 0.59 to 0.73 (moderate to good) for a diagnosis of CHM, from 0.15 to 0.43 (poor to moderate) for PHM, and from 0.13 to 0.42 (poor to moderate) for NM. The κ values for intraobserver agreement ranged from 0.44 to 0.67 (moderate to good). Addition of the p57 immunostain improved sensitivity of a diagnosis of CHM to a range of 93% to 96% for individual pathologists and 96% by consensus; specificity was improved from a range of 96% to 98% for individual pathologists and 96% by consensus; there was no substantial impact on diagnosis of PHMs and NMs. Interobserver agreement for interpretation of the p57 immunostain was 0.96 (almost perfect). Even with morphologic assessment by gynecologic pathologists and p57 immunohistochemistry, 20% to 30% of cases will be misclassified, and, in particular, distinction of PHMs and NMs will remain problematic.

Downregulation of ASPP1 in gestational trophoblastic disease: correlation with hypermethylation, apoptotic activity and clinical outcome

Gestational trophoblastic disease encompasses a spectrum of trophoblastic lesions including true neoplasms such as choriocarcinomas and the potentially malignant hydatidiform moles, which may develop persistent disease requiring chemotherapy. ASPP1, a member of apoptosis-stimulating proteins of p53 (ASPPs), is a proapoptotic protein that can stimulate apoptosis through its interaction with p53. We evaluated the promoter methylation and expression profiles of ASPP1 in different trophoblastic tissues and its in vitro functional effect on two choriocarcinoma cell lines, namely JEG-3 and JAR. Significant downregulation of ASPP1 mRNA and protein levels was demonstrated in hydatidiform moles and choriocarcinomas, when compared with normal placentas by quantitative-PCR and immunohistochemistry. The ASPP1 mRNA level was significantly correlated with its hypermethylation status, evaluated with methylation-specific PCR, in placenta and gestational trophoblastic disease samples (P=0.024). Moreover, lower ASPP1 immunoreactivity was shown in hydatidiform moles that progressed to persistent gestational trophoblastic neoplasms than in those that regressed (P=0.045). A significant correlation was also found between expression of ASPP1 and proliferative indices (assessed by Ki67 and MCM7), apoptotic activity (M30 CytoDeath antibody), p53 and caspase-8 immunoreactivities. An in vitro study showed that ectopic expression of ASPP1 could trigger apoptosis through intrinsic and extrinsic pathways as indicated by an increase in cleaved caspase-9 and Fas ligand protein expression. The latter suggests a hitherto unreported novel link between ASPP1 and the extrinsic pathway of apoptosis. Our findings suggest that downregulation of ASPP1 by hypermethylation may be involved in the pathogenesis and progress of gestational trophoblastic disease, probably through its effect on apoptosis.

p21-Activated kinase-1 promotes aggressive phenotype, cell proliferation, and invasion in gestational trophoblastic disease

Gestational trophoblastic disease (GTD) includes hydatidiform mole (HM), which can develop persistent gestational trophoblastic neoplasia requiring chemotherapy; choriocarcinoma, which is a frankly malignant tumor; placental site trophoblastic tumor; and epithelioid trophoblastic tumor. p21-Activated kinases (PAKs) promote malignant tumor progression. Therefore, this study investigated PAK1, PAK2, and p-PAK2 Ser(20) in the pathogenesis of GTD. By real-time PCR, PAK1 mRNA was significantly higher in HMs, particularly metastatic HMs (P = 0.046) and HMs that developed persistent disease (P = 0.011), when compared with normal placentas. By immunohistochemistry, significantly increased cytoplasmic PAK1 immunoreactivity in cytotrophoblasts was also detected in HMs (P = 0.042) and choriocarcinomas (P = 0.003). In addition, HMs that developed persistent disease displayed higher PAK1 immunoreactivity than those that regressed (P = 0.016), and elevated PAK1 immunoreactivity was observed in placental site trophoblastic tumors. Indeed, there was significant positive correlation between PAK1 expression and the proliferative indices Ki-67 (P = 0.016) and MCM7 (P = 0.026). Moreover, higher PAK1 mRNA and protein expression was confirmed in the choriocarcinoma cell-lines JEG-3 and JAR; however, PAK2 mRNA and p-PAK2 immunoreactivity showed a similar expression pattern in normal first trimester placentas and GTD. Knockdown of PAK1 in JEG-3 and JAR reduced cell proliferation, migration, and invasion ability, up-regulated p16, and down-regulated vascular endothelial growth factor and MT1-MMP expression. This is the first report revealing the involvement of PAK1 in the pathogenesis and clinical progress of GTD.

Activated Stat3 expression in gestational trophoblastic disease: correlation with clinicopathological parameters and apoptotic indices

AIMS

To assess the expression profile of the activated form of signal transducer and activator of transcription (Stat)3 in gestational trophoblastic disease (GTD) and correlate the findings with clinicopathological parameters.

METHODS AND RESULTS

By immunohistochemistry, both cytoplasmic and nuclear expression of p-Stat3-Ser(727) was demonstrated in 88 trophoblastic tissues, including placentas and GTD. Nuclear immunoreactivity of p-Stat3-Ser(727) was significantly higher in hydatidiform mole (HM) (P < 0.001) and choriocarcinoma (P = 0.009) when compared with normal placentas. Placental site trophoblastic tumours (PSTT) and epithelioid trophoblastic tumours (ETT) also demonstrated higher nuclear p-Stat3-Ser(727) expression than their normal trophoblast counterparts. Higher p-Stat3-Ser(727) expression was confirmed in choriocarcinoma cell lines, JEG-3 and JAR, than in a normal trophoblast cell line, with both nuclear and cytoplasmic fractions demonstrated by immunoblotting. Spontaneously regressed HM showed significantly increased nuclear and cytoplasmic p-Stat3-Ser(727) immunoreactivity over those that developed gestational trophoblastic neoplasia (GTN) (P = 0.013, P = 0.039). There was a significant positive and inverse correlation between nuclear p-Stat3-Ser(727) immunoreactivity and apoptotic indices [terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick end labelling and M30 CytoDeath antibody] (P = 0.001, P < 0.001, Spearman's rho test) and Bcl-2 expression (P = 0.034), respectively.

CONCLUSIONS

p-Stat3-Ser(727) plays a role in the pathogenesis of GTD, probably through the regulation of apoptosis. p-Stat3-Ser(727) immunoreactivity is a potential marker in predicting GTN in HM.

Overexpression of NANOG in gestational trophoblastic diseases: effect on apoptosis, cell invasion, and clinical outcome

Gestational trophoblastic disease includes choriocarcinoma, a frankly malignant tumor, and hydatidiform mole (HM), which often leads to the development of persistent gestational trophoblastic neoplasia and requires chemotherapy. NANOG is an important transcription factor that is crucial for maintaining embryonic stem cell self-renewal and pluripotency. We postulated that NANOG is involved in the pathogenesis of gestational trophoblastic disease. In this study, significantly higher NANOG mRNA and protein expression levels, by quantitative PCR and immunoblotting, respectively, were demonstrated in HMs, particularly those that developed persistent disease, when compared with normal placentas. In addition, significantly increased nuclear NANOG immunoreactivity was found by immunohistochemistry in HMs (P < 0.001) and choriocarcinoma (P = 0.002). Higher NANOG expression levels were demonstrated in HMs that developed persistent disease, as compared with those that regressed (P = 0.025). Nuclear localization of NANOG was confirmed by confocal microscopy and immunoblotting in choriocarcinoma cell lines. There was a significant inverse correlation between NANOG immunoreactivity and apoptotic index assessed by M30 CytoDeath antibody (P = 0.012). After stable knockdown of NANOG in the choriocarcinoma cell line JEG-3 by an shRNA approach, increased apoptosis was observed in relation to with enhanced caspases and poly(ADP-ribose) polymerase activities. NANOG knockdown was also associated with decreased mobility and invasion of JEG-3 and down-regulation of matrix metalloproteases 2 and 9. These findings suggest that NANOG is involved in the pathogenesis and clinical progress of gestational trophoblastic disease, likely through its effect on apoptosis, cell migration, and invasion.

Morphological, immunohistochemical and chromosome in situ hybridization in the differential diagnosis of Hydatidiform Mole and Hydropic Abortion

OBJECTIVE

To explore the utility of histological, immunohistochemical and chromosome in situ hybridization (CISH) test in the differential diagnosis of Complete Hydatidiform Mole (CHM), Partial Hydatidiform Mole (PHM) and Hydropic Abortion (HA).

STUDY DESIGN

We analyzed the histological characteristics, p57kip2 and Factor VIII expression and CISH test in 38 cases with some diagnostic concerns, comprising 13 CHM, 14 PHM and 11 HA.

RESULTS

Our results indicate that p57kip2 expression and the ploidy assessed by CISH were essential for the reclassification of 2 cases, one from CHM to PHM and another from PHM to HA, as well as for confirming the previous diagnosis in cases where there were conflicting features. p57kip2 expression is diagnostic if no cells at all present it (CHM) or when there are over 10% of cells expressing it (PHM and HA).

CONCLUSIONS

We concluded that there is no single criterion for the distinction of CHM, PHM and HA. So p57kip2 expression and CISH test can be used in association with the histological findings for the differential diagnosis of the three conditions in cases presenting some concern for definitive diagnosis.

Melanin as a potential target for radionuclide therapy of metastatic melanoma

Melanoma is diagnosed in approximately 100,000 patients worldwide and for those with metastatic disease, the 5-year survival is extremely poor at just 6%, because there are no satisfactory treatments. Targeted radionuclide therapy is currently gaining momentum and has evolved into an efficient modality for the treatment of patients with malignancies such as non-Hodgkins lymphoma in whom standard antineoplastic therapies are not effective. Melanoma is named after the pigment melanin, which in turn is derived from the Greek word for black. Most melanomas are pigmented by the presence of melanin, some of which is extracellular as a result of cellular turnover. Thus, melanin presents a promising target for the drugs carrying a cytotoxic payload of radiation provided such therapies spare other melanotic tissues. There are a variety of substances that could potentially serve as delivery vehicles of radionuclides for the treatment of melanoma. These substances can be divided into melanin binders, melanin precursors and binders to melanogenesis-related proteins. The authors are optimistic that therapeutic agents targeting melanin to deliver radionuclide therapy could appear in the clinic within a decade.

Predictors of Low Risk of Persistent Trophoblastic Disease in Molar Pregnancies

OBJECTIVE

To search for predictive factors for low risk of persistent trophoblastic disease in patients with molar pregnancies.

METHODS

A total of 270 consecutively collected, histologically confirmed hydatidiform moles were classified by ploidy using karyotyping and flow cytometry. The parental origin of the genome was determined by analysis of microsatellite polymorphisms. Data on clinical features and pathology reports were collected for each patient.

RESULTS

The observed frequency of persistent trophoblastic disease in patients with triploid moles was 0 of 105, (95% confidence interval 0-2.8%), whereas 28 of 162 patients with diploid molar pregnancies developed persistent trophoblastic disease (P < .001). Patients with a diploid mole and an initial hCG level lower than 49,000 units per liter did not develop persistent trophoblastic disease (P = .03).

CONCLUSION

The risk of persistent trophoblastic disease after a triploid mole is very low. By combining the present data with data from published studies with valid ploidy assessment, the frequency of persistent trophoblastic disease in patients with triploid moles is 0 of 196 (95% confidence interval 0-1.5%). We suggest that the surveillance program for patients with triploid molar pregnancies is shortened. Initial hCG less than 49,000 units per liter is a possible predictor of low risk of persistent trophoblastic disease in women with diploid molar pregnancies, but this observation needs confirmation in larger studies.

Differential Gene Expression Identified in Complete Hydatidiform Mole by Combining Suppression Subtractive Hybridization and cDNA Microarray

Complete hydatidiform mole (CHM) is a type of gestational trophoblastic disease with pure paternal chromosome contribution and unpredictable malignant potential. As an attempt to assess the molecular pathogenesis of CHM, suppression subtractive hybridization (SSH) combined with cDNA microarray was used to compare the gene expression pattern of CHM compared with normal first-trimester placenta of similar gestational ages. cDNA microarray analysis using tissue-specific chips constructed with subtracted cDNA libraries identified 13 differentially expressed gene transcripts. Quantitative real-time polymerase chain reaction (PCR) confirmed up-regulation of human chorionic gonadotropin beta subunit (CGB) (P=0.0008) and KIAA1200 (P=0.0005), a G-protein regulator, as well as down-regulation of osteopontin (SPP1) (P<0.0001) in 14 genotyped CHM when compared with 15 normal placentas. These candidate genes may contribute toward understanding the mechanism involved with the development and progression of CHM.

Caspase activity is downregulated in choriocarcinoma: a cDNA array differential expression study

BACKGROUND

Placental trophoblast can be considered to be pseudomalignant tissue and the pathogenesis of gestational trophoblastic diseases remains to be clarified.

AIMS

To examine the role of caspases 8 and 10, identified by differential expression, on trophoblast tumorigenesis.

METHODS

cDNA array hybridisation was used to compare gene expression profiles in choriocarcinoma cell lines (JAR, JEG, and BeWo) and normal first trimester human placentas, followed by confirmation with quantitative real time polymerase chain reaction and immunohistochemistry. Caspase 10 and its closely related family member caspase 8 were analysed.

RESULTS

Downregulation of caspase 10 in choriocarcinoma was detected by both Atlastrade mark human cDNA expression array and Atlastrade mark human 1.2 array. Caspase 10 mRNA expression was significantly lower in hydatidiform mole (p = 0.035) and chorioarcinoma (p = 0.002) compared with normal placenta. The caspase 8 and 10 proteins were expressed predominantly in the cytotrophoblast and syncytiotrophoblast, respectively, with significantly lower expression in choriocarcinomas than other trophoblastic tissues (p < 0.05). Immunoreactivity for both caspase 8 and 10 correlated with the apoptotic index previously assessed by terminal deoxynucleotidyl transferase mediated dUTP nick end labelling (p = 0.02 and p = 0.04, respectively) and M30 (p < 0.001 and p = 0.003, respectively) approaches.

CONCLUSIONS

These results suggest that the downregulation of capases 8 and 10 might contribute to the pathogenesis of choriocarcinoma.

Choriocarcinoma and gestational trophoblastic disease

Gestational trophoblastic disease (GTD) encompasses a unique group of uncommon but interrelated conditions derived from placental trophoblasts. For the purposes of discussion GTD is the appropriate collective name for hydatidiform mole, whereas the term gestational trophoblastic neoplasia (GTN) is reserved for cases with persistent human chorionic gonadotropin (hCG) titer elevation after evacuation of hydatidiform mole, metastatic disease, or choriocarcinoma. Although the pathology and clinical behavior of CM and PM are different, the initial management of both conditions is surgical evacuation by suction curettage, determination of the baseline, and follow-up with (hCG) titers. There are guidelines for risk-factor scoring and a staging system that classifies untreated patients into distinct prognostic categories so that treatment outcomes can be objectively compared. The rates of GTN and choriocarcinoma are decreasing and survival has dramatically improved.

Analysis of chromosome 7 in adult and pediatric ependymomas using chromogenic in situ hybridization

Few studies have yielded reliable data that distinguish between ependymal neoplasms based on molecular genetic attributes. The present study utilizes chromogenic in situ hybridization (CISH), a relatively recent hybridization technique, to retrospectively examine chromosome 7-copy number in pediatric and adult ependymomas. Of the 27 hybridizations, polysomy of chromosome 7 was detected in 10 out of 15 (66%) adult ependymomas, and in only three out of 12 (25%) pediatric lesions. All myxopapillary ependymomas showed polysomy. The remaining tumors were diploid. The authors conclude that (1) there are distinct genetic subsets of ependymoma, in particular, increases in copy number of chromosome 7 are almost exclusively found in myxopapillary ependymoma, and that (2) CISH is a rapid and sensitive method of stratifying morphological variants of ependymoma and potentially other central nervous system (CNS) tumors. These results encourage further investigations with CISH on a larger scale to determine its merit as an ancillary diagnostic and prognostic tool.

Gestational trophoblastic diseases: recent advances in histopathologic diagnosis and related genetic aspects

Gestational trophoblastic disease refers to a spectrum of proliferative disorders of the placental trophoblast, with a wide range of histologic appearances and clinical behaviors. This review discusses the more recent developments in the diagnosis of these entities. Changes in criteria for the histologic diagnosis of these lesions due to earlier clinical diagnosis are reviewed, and the ability to make more accurate diagnoses due to the introduction of newer antibodies such as p57 is highlighted. A discussion of epithelioid trophoblastic tumor, a newly introduced tumor subtype, with its differential diagnosis from placental-site trophoblastic tumor and squamous cell carcinoma is also presented. Last, a brief discussion on the role of genetic studies and the future direction of research in elucidating the nature of this intriguing group of lesions is presented.

Differential expression of insulin-like growth factor binding protein 1 and ferritin light polypeptide in gestational trophoblastic neoplasia

BACKGROUND

Hydatidiform mole (HM), the most common type of gestational trophoblastic diseases, can be considered as placenta with abnormal chromosome composition with potential of malignant transformation. Few biologic markers can predict subsequent development of persistent gestational trophoblastic neoplasia (GTN) requiring chemotherapy.

METHODS

Suppression subtractive hybridization (SSH) combined with cDNA microarray was used to compare the differential expression pattern of HM that spontaneously regressed and that subsequently developed metastatic GTN. Tissue-specific chips were constructed from the subtracted cDNA libraries, followed by cDNA microarray analysis. Verification by quantitative RNA analysis by real-time polymerase chain reaction (PCR) and immunohistochemical analysis was performed in 23 genotyped complete HM.

RESULTS

Sixteen differentially expressed transcripts were identified. Quantitative RNA analysis confirmed down-regulation of ferritin light polypeptide (FTL) (P = 0.037) and insulin-like growth factor binding protein 1 (IGFBP1) (P = 0.037) in HM that subsequently developed GTN when compared with those HM that regressed. Immunohistochemical analysis further confirmed reduced IGFBP1 protein (P = 0.03) expression in HM that developed GTN.

CONCLUSIONS

Findings showed that reduced expression of genes related to cell invasion and immunosuppression, especially FTL and IGFBP1, were associated with development of GTN, and this finding may provide a better understanding of the pathogenesis of GTN. The potential application of FTL and IGFBP1 in management of patients with HM should be explored.

Mcl-1 expression in gestational trophoblastic disease correlates with clinical outcome

BACKGROUND

Hydatidiform moles (HMs) are abnormal pregnancies with a propensity for developing persistent disease in the form of gestational trophoblastic neoplasia (GTN), which requires chemotherapy. In previous studies, the authors demonstrated that low apoptotic activity was correlated with the progression of HM to GTN, and they hypothesized that some apoptosis-related genes may determine this progression.

METHODS

The differential expression of apoptotic genes in HMs that subsequently developed into GTN was compared with the same expression in HMs that spontaneously regressed using a human apoptosis array; then, the expression was evaluated with real-time quantitative polymerase chain reaction analysis and immunohistochemistry using 54 clinical samples from patients with HMs who had follow-up data available.

RESULTS

Using an apoptosis array, greater expression of Mcl-1, which is an antiapoptotic gene, was detected in HMs that subsequently developed into GTN. It was confirmed that the levels of Mcl-1 RNA expression (P = 0.017) and Mcl-1 protein expression (P < 0.001) in HMs that developed into persistent disease and required chemotherapy were significantly greater compared with the levels in HMs that regressed. Moreover, Mcl-1 immunoreactivity, which was detected predominantly in cytotrophoblasts, was correlated with the apoptotic index, as assessed with M30 cytoDeath immunohistochemistry, which is a good indicator of apoptotic events in the early-stage disease.

CONCLUSIONS

The current results demonstrated that Mcl-1, as identified by a cyclic DNA array, may play a role in the pathogenesis of HMs and may have potential as a useful marker for predicting the clinical behavior of HMs.