Trophoblastic cells expressing human chorionic gonadotropin genes in peripheral blood of patients with trophoblastic disease

We attempted to identify the cells expressing alpha and beta subunits of human chorionic gonadotropin (hCG) in the peripheral blood of patients with trophoblastic disease and normal pregnant women by using reverse transcriptase polymerase chain reaction (RT-PCR) and Southern blot. By this method, the mRNAs of hCG alpha and hCG beta were detected in the peripheral blood mononulear cells (PBMNC) from 3 of 7 hydatidiform mole (mole) and 1 of 4 choriocarcinoma patients as well as from normal pregnant women during the first trimester. None of the mRNAs of hCG subunits was detected in the PBMNC from healthy male and nonpregnant healthy women examined. The expression of hCG alpha and hCG beta in patients with trophoblastic disease and normal pregnant women almost correlated with their plasma levels of intact hCG. The present study indicates that the cells expressing hCG alpha and hCG beta, which virtually represent trophoblasts, are circulating in the peripheral blood of patients with trophoblastic disease as well as of normal pregnant women.

Recent advances in gestational trophoblastic disease

Advances in the last 20 years have led to a better understanding of the process of gestational trophoblastic disease (GTD), and consequently, to improved diagnosis, management, and prognosis. Patients with GTD should be registered at a trophoblastic disease center for follow-up, and those with persistent disease should receive chemotherapy, methotrexate, and folinic acid for low-risk disease, and EMACO (etoposide, actinomycin-D, methotrexate, vincristine, and cyclophosphamide) for high-risk disease, without loss of fertility. Most patients with relapsing or resistant disease can be treated effectively with surgery and/or cisplatin in EP/EMA (etoposide, platinum-etoposide, methotrexate, actinomycin-D) combination.

Studies of non-disjunction in trisomies 2, 7, 15, and 22: does the parental origin of trisomy influence placental morphology?

Recently, there have been several molecular studies of trisomic fetuses and liveborns which have examined the parent and meiotic stage of origin of nondisjunction. However, little is known about the possible phenotypic effects of the origin of trisomy. For trisomic spontaneous abortions, no distinct phenotype has been described, although some have been reported to have features, such as trophoblastic hyperplasia, similar to hydatidiform moles. In the present report, we describe molecular and histological studies of spontaneous abortions with trisomies 2, 7, 15, or 22, conditions occasionally linked to trophoblastic hyperplasia. Our results provide strong evidence for chromosome specific mechanisms of nondisjunction, with trisomy 2 having a high frequency of paternally derived cases and trisomy 7 typically originating postzygotically. In studies correlating parental origin of trisomy with phenotype, we found no difference in the proportion of cases with trophoblastic hyperplasia, fetal tissue, nucleated red blood cells, or hydropic villi among paternally or maternally derived trisomies 2, 7, 15, or 22. However, paternally derived trisomies tended to abort earlier than maternally derived trisomies. This suggests that parental origin might affect the developmental stage at which abortion occurs but not other features of placental phenotype.

DOC-2/hDab2, a candidate tumor suppressor gene involved in the development of gestational trophoblastic diseases

Gestational trophoblastic diseases comprise a spectrum of interrelated diseases including partial mole, complete mole and gestational choriocarcinoma. Using reverse transcriptase PCR (RT-PCR) analysis, we identified higher levels of DOC-2/hDab2 expression in the normal trophoblast cells in culture than in choriocarcinoma cell lines. Subsequent study using immunohistochemistry showed high levels of DOC-2/hDab2 protein expression in normal trophoblast tissues but significantly lower levels of expression in gestational trophoblastic disease tissues, particularly in complete mole and choriocarcinoma. When DOC-2/hDab2 was transfected into the choriocarcinoma cell lines, Jar, JEG and BeWo, the stable transfectants showed significantly reduced growth rate in culture. These data suggest that down regulation of DOC-2/hDab2 may play an important role in the development of gestational trophoblastic diseases.

Prevalence of the partial molar phenotype in triploidy of maternal and paternal origin

Triploid partial moles are at risk for trophoblastic neoplasia, yet the prevalence, parent of origin, and evolution of the partial molar phenotype amongst all triploids remains controversial. We determined parental origin by polymerase chain reaction (PCR) analysis, stage of development by gross and histological criteria, and partial molar status according to strict diagnostic criteria for all triploids identified amongst 1,054 consecutively karyotyped spontaneous abortions. Triploidy was detected in 64 of 832 successfully karyotyped specimens. Complete data were collected in 59 cases. Diandric origin was found in 39 specimens, and 20 of these fulfilled all four criteria for partial mole (trophoblast hyperplasia, dimorphic population of large and small villi, villous hydrops greater than 0.5 mm, and irregular villous contour). We separated the 19 diandric triploids not fulfilling all criteria for partial mole into four groups: specimens of early developmental stage, which we believed represented developing ("early") partial moles (n = 3), cases of late developmental stage, which we believed represented involuting ("ancient") partial moles (n = 4), cases showing some but not all criteria for partial mole (n = 7), and specimens with few if any criteria suggestive of partial mole (n = 5). In triploids of digynic origin (n = 20), developmental stage was significantly lower, fetal tissue was more frequently identified, and all specimens showed well-preserved fetal red blood cells. Digynic triploids occasionally showed irregular contour, dimorphic villi, and a mild form of trophoblast hyperplasia but never showed hydropic degeneration and were never suspicious for partial mole.

New concepts in trophoblastic growth and differentiation with practical application for the diagnosis of gestational trophoblastic disease

Human trophoblast in normal implantation and placentation appears to undergo two different pathways of differentiation resulting in the development of villous and extravillous trophoblast. Cytotrophoblast (CT) differentiates abruptly into syncytiotrophoblast (ST) on the villous surface as compared with the spectrum of differentiation exhibited by extravillous trophoblast where CT differentiates into intermediate trophoblast (IT) and then into multinucleated intermediate trophoblastic cells (MITC). The various types of gestational trophoblastic lesions can be defined and related to discrete pathologic aberrations occurring at different stages of trophoblastic differentiation. The rapid advance in the discovery of new trophoblastic markers has facilitated the molecular dissection of the lineage and differentiation stages of trophoblast and related these to various trophoblastic lesions. Furthermore, antibodies against these markers, especially those that are able to recognize formalin-resistant epitopes, have considerable value in the study and differential diagnosis of different types of gestational trophoblastic disease.

Gestational trophoblastic disease. Molecular and genetic studies

For a geneticist, the gestational trophoblastic diseases are a particularly interesting group of diseases. Hydatidiform moles were one of the first of a growing number of human disorders shown to result from the phenomenon of genomic imprinting, while gestational trophoblastic tumors are unusual neoplasms in that they derive not from the patients' own tissue but from a genetically distinct pregnancy. We review here the development of our understanding of the genetics of gestational trophoblastic disease and describe how modern molecular genetic techniques can be used to aid in the management of these conditions and further our understanding of their unusual biology.

A subset of gestational trophoblastic disease characterized by abnormal chromosome 8 copy number detected by fluorescence in situ hybridization

The present paper describes the results of research conducted to ascertain whether the report by Mark et al. [1], describing the concurrence of congenital trisomy 8 mosaicism and gestational trophoblastic disease (GTD) in a 42 year-old Gravida IV, Para IV patient was an isolated event. In contrast to other cases described in the literature, the patient described in Mark et al. [1] had no additional confounding chromosomal abnormalities other than trisomy 8. To the best of our knowledge, ours was the only reported case of constitutional trisomy 8 mosaicism associated with gestational trophoblastic disease, a rare gynecological disease entity. The question arises whether there exists a subset of patients with GTD characterized by an abnormal chromosome 8 copy number. The implicit hypothesis is that an abnormal number of chromosome 8 somehow predisposes to cancer. A pilot study of 10 cases of GTD was conducted using fluorescence in situ hybridization (FISH) and a commercial chromosome 8-specific alpha-satellite probe on formalin-fixed, paraffin-embedded patient tissues. Among eight informative cases successfully completed, two cases (25%) were found to be trisomic, when a cut-off point of 10% trisomic cells is adopted. Another two cases (25%) were found to be triploid. The results of our FISH study indicated that an abnormal chromosome 8 copy number found in Mark et al. [1] is unlikely to be an isolated event. Our data are consistent with the hypothesis that a subset of GTD indeed may exist which is characterized by more than two copies of chromosome 8. The present findings corroborate those recently found in breast, prostate, and other cancers.

Genetic aspects of gestational trophoblastic diseases: a general overview with emphasis on new approaches in determining genetic composition

All gestational trophoblastic tumors are derived from a fertilization event. In the hydatidiform moles, varying degrees of excess paternal DNA lead to varying histopathologic forms of these tumors. The placental site trophoblastic tumors and the choriocarcinomas may follow normal pregnancy, abortions and hydatidiform moles, and, thus evince a wide range of genetic compositions reflecting their gestation of origin. Advances in molecular biological diagnoses now allow for the determination of the gestational or non-gestational origin of trophoblastic tumors, and, may well provide fantastic new insights into the biology of these unusual tumors.

C-erbB-2 amplification and expression in gestational trophoblastic disease correlates with DNA content and karyotype

The subject of this retrospective study was to evaluate the potential benefit of the c-erbB-2 oncogene amplification and expression in 27 complete hydatidiform moles as well as in 9 cases of persistent gestational trophoblastic disease defined by elevated serum beta-human choriongonadotropin. The persistent cases were histopathologically classified as 5 complete hydatidiform moles, 3 invasive moles and 1 choriocarcinoma. In addition, we determined the DNA content and the karyotype of the sex chromosomes. The data were correlated with the histopathologic characteristics of gestational trophoblastic diseases. Cases with c-erbB-2 amplification and expression in combination with DNA hyperploidy showed higher proliferation and a more aggressive behavior (2 complete hydatidiform moles with lung and liver metastases, 2 invasive moles and 1 choriocarcinoma). XY karyotype was evident in the choriocarcinoma and in two complete hydatidiform moles with advanced stage and DNA hyperploidy.

Human chorionic gonadotrophin-beta gene sequences in women with disorders of HCG production

Women with recurrent abortion, primary unexplained infertility, and gestational trophoblastic neoplasia (GTN) manifest disordered human chorionic gonadotrophin (HCG) secretion. Mutations in the HCG beta/luteinizing hormone (LH) beta gene complex could cause aberrant HCG production in these disorders. The purpose of this study was to determine whether HCG beta gene deletions occur in women with recurrent abortion or primary unexplained infertility, and whether HCG beta gene duplications are present in women with GTN. DNA was extracted from 10 patients with unexplained recurrent abortion, 10 patients with unexplained primary infertility, 12 patients with GTN, three partners of women with GTN, and 30 controls. Southern blots were constructed and hybridized with DNA probes for HCG beta-5 and the LH beta gene. No gene deletions were identified in patients with recurrent abortion or primary unexplained infertility. Likewise, no gene duplications were identified in women with GTN. A previously described Mbol restriction fragment length polymorphism (RFLP) was identified in both patients and controls. A new Pstl RFLP was also characterized, but was present in patients and controls. Deletion/duplication mutations in the HCG beta/LH beta gene complex do not appear to be common causes of aberrant HCG production in humans with these disorders.

Intracytoplasmic sperm injection combined with preimplantation genetic diagnosis for the prevention of recurrent gestational trophoblastic disease

A strategy for the prevention of repeated molar pregnancies by using intracytoplasmic sperm injection (ICSI) coupled with preimplantation genetic diagnosis (PGD) with fluorescence in-situ hybridization (FISH) was developed. In this approach, complete moles which arise from dispermic fertilization are avoided by the use of ICSI. ICSI is followed by preimplantation selection against the transfer of 46,XX embryos, thus preventing complete moles resulting from a fertilization of an inactive oocyte, by a haploid X-bearing spermatozoon which subsequently duplicates. Triploid partial moles which arise mainly from dispermic fertilization may also be prevented by ICSI. The preimplantation confirmation of diploidy by FISH guards against triploid partial moles which may result from mechanisms other than dispermic fertilization. The employment of this strategy in an attempt to prevent a repeated event of molar pregnancy in a patient with a history of two previous episodes of gestational trophoblastic disease is reported.

Gestational trophoblastic disease following the evacuation of partial hydatidiform mole: a review of 66 cases

OBJECTIVE

The current study was undertaken in order to identify the clinical characteristics and natural history, as well as methods of investigation and available therapy, of persistent gestational trophoblastic disease (GTD) following the evacuation of partial hydatidiform mole (PM).

METHODS

Case reports of persistent GTD following the evacuation of partial mole, were searched using the Medline computerized retrieval system. There were 66 such cases (including 4 cases treated at our department), representing 2.9% of GTD following PM.

RESULTS

The mean age of the women at diagnosis was 28.4 years and mean gravidity was 2.99. The mean gestational age at diagnosis was 15.5 weeks and the mean uterine size was 13.6 weeks. The most common presenting symptom was vaginal bleeding. In the majority of the patients, the pre-evacuation diagnosis was incomplete or missed abortion.

CONCLUSIONS

Although the malignant potential of PM is low, persistent GTD may develop after PM and may even metastasize, it is usually responsive to single agent chemotherapy but may require combination chemotherapy. Therefore, after evacuation of PM, these women should be followed with serial serum b-hCG. Further research is needed to enable earlier identification of PM that eventually will develop persistent GTD.

Gestational trophoblastic disease

GTD occurs in fewer than 1 in 1200 pregnancies in the United States, but it is much more common in Asia and Latin America, where its incidence may be as high as 1 in 200 pregnancies. Risk factors for GTD include advanced or young maternal age, low socioeconomic status, and prior hydatidiform mole. Early diagnosis and prompt treatment are key to a favorable outcome, and thus recognition of the signs and symptoms of the disease is important for all physicians. Because these diseases have low incidences and occur after reproductive events, screening for them in the general population is not worthwhile. No chemopreventive agents have yet been studied in women at risk for GTD, but the oral contraceptive is a good candidate.

Placental site trophoblastic tumor: molecular analysis and clinical experience

Placental site trophoblastic tumor is a very rare variant of gestational trophoblastic disease which differs histologically and immunocytochemically from gestational choriocarcinoma. The English language literature includes only 74 reported cases. Seventeen patients have been managed at Charing Cross Hospital with this diagnosis. The median follow-up is 4.6 years, and the 5-year overall survival is 80% (95% confidence interval, 55-93%). Multivariate regression analysis identified an interval of >2 years since the preceding pregnancy as an independent adverse prognostic factor. Genotypic analysis by PCR allelotyping has confirmed the gestational origin of all 11 tumors successfully studied. More detailed molecular analysis has identified the causative pregnancy for eight tumors. Five were diploid biparental tumors following term pregnancies, and three were androgenetic tumors following monospermic complete hydatidiform moles.

Malignant trophoblastic neoplasms with different modes of origin

The genetic origin of 24 trophoblastic neoplasms was determined using PCR polymorphisms. Based on pregnancy history, these tumors included nine postmolar trophoblastic tumors, 12 tumors preceded by live birth or abortion, and three nongestational tumors. Androgenetic origin was defined in eight post-molar trophoblastic tumors, and the remaining one might have arisen from a normal fertilization. Six tumors retained genetic features carried by the homozygous complete mole. Two tumors showed PCR polymorphism compatible with that of the heterozygous complete mole. All 12 tumors in the second class had alleles of both paternal and maternal contribution. However, discordance of sex between the antecedent pregnancy product and the tumor was recognized in three choriocarcinomas. The absence of paternal contribution suggested a parthenogenetic origin of three nongestational choriocarcinomas. The findings that PCR polymorphisms were either homozygous in certain loci or heterozygous in others may mean that the tumor was derived from a germ cell after meiosis I. As a result, at least three subtypes with different modes of origin were demonstrated in the 24 trophoblastic tumors. These findings underscore the importance of precise genetic marker analyses in a large series to clearly identify clinical and biologic characteristics of each subset of tumors.

Gestational trophoblastic diseases: current trends and perspectives

Gestational trophoblastic diseases (GTD) include a spectrum of diseases from the potentially premalignant hydatidiform mole to the highly aggressive choriocarcinoma. Most complete moles have diploid chromosomes, nearly always of pure paternal origin, whereas most partial moles have triploid chromosomes, containing one haploid maternal set and two paternal sets. The first-line treatment of molar pregnancies is suction evacuation. In patients with persistent trophoblastic diseases or choriocarcinoma, single agent or multiagent chemotherapy is indicated, depending on the prognostic score of the individual patient. With careful follow-up and appropriate treatment, nearly all patients with gestational trophoblastic diseases can be cured. Although many advances have been made in the cytogenetics, molecular biology and immunobiology of GTD, the reasons for its unique curability remain unclear. Studies comparing induction of apoptosis and multidrug resistance gene expression, in normal trophoblasts and GTD, may elucidate the mechanism behind the good response of GTD to chemotherapy. This may give some innovative insight into chemoresistance.

Fluorescent in situ hybridization assessment of chromosome copy number in gestational trophoblastic disease

The concurrence of congenital trisomy 8 mosaicism and gestational trophoblastic disease in a forty-two-year-old Gravida IV, Para IV female has been described. In contrast to other cases in the literature, this patient had no additional confounding chromosomal abnormalities other than trisomy 8. To the best of our knowledge, this was the only reported case of constitutional trisomy 8 mosaicism associated with gestational trophoblastic disease, a rare gynecological disease entity in and by itself. The present report describes fluorescent in situ hybridization (FISH) studies for assessing chromosome 8 copy number on various patient tissues. The results of the FISH studies are compared with each other and with the original cytogenetic studies. It is concluded that the overall frequency of trisomy 8 cells is lower in the FISH studies using archival material than in the original conventional cytogenetic studies. This is true for the uterus and lung tissues with a metastatic tumor. The possible reasons for the somewhat different frequencies found between conventional cytogenetics via GTG-banding and interphase cytogenetics via FISH are discussed.

Ploidy analysis by flow cytometry and fluorescence in situ hybridization in hydropic placentas and gestational trophoblastic disease

Placentas with hydropic change may be hydropic degeneration (HD) or gestational trophoblastic disease (GTD), partial (PM) or complete (CM) hydatidiform mole. The separation of HD from PM and PM from CM by histological findings may be problematic in some cases and can be clarified with ploidy analysis. Fluorescence in situ hybridization (FISH) using a probe to chromosome 7 (D7Z1) was applied to tissue cut from paraffin blocks from 10 histologically representative cases each of HD, PM, and CM on which ploidy had been previously confirmed by flow cytometry from paraffin embedded tissue. Villous stromal cells and nonproliferative trophoblast were examined for number of signals/cell and percentage of cells/placenta with three hybridization signals. The mean number of hybridization signals/cell was HD 1.14; PM 1.79; and CM 1.17, with statistical significance between HD and PM (P < .0001), and PM and CM (P < .0001). The mean percentage of cells/placenta with three hybridization signals was HD 1.10%, PM 23.1%, and CM 2.11%, with statistical significance between HD and PM (P < .0001), and PM and CM (P < .0001). In addition, there was no overlap in the mean percentage of cells with three hybridization signals between HD and PM, and PM and CM. Chromosome 2 probe (D2Z1) was applied to tissues that had three chromosome 7 signals to exclude trisomy, and in all cases three signals were present confirming triploidy in PM. FISH can identify diploid and triploid hydropic placentas in paraffin-embedded tissue to assist in differentiating HD from PM, and PM from CM.

p53 expression in gestational trophoblastic disease

The p53 expression of normal trophoblasts (11 cases), partial moles (11 cases), complete moles (19 cases), and gestational choriocarcinoma (eight cases) were studied. We found that p53 is frequently expressed in gestational choriocarcinoma and in hydatidiform moles (mainly cytotrophoblasts), whereas syncytiotrophoblasts are generally spared. This finding supports the view that p53 expression is a reflection of proliferative capacity of cells rather than an indicator of neoplastic or malignant transformation. The greater p53 expression observed in complete moles as compared with partial moles is in keeping with the more pronounced trophoblastic hyperplasia and proliferative activity of complete moles. More interesting was the observation that p53 expression was also noted in normal trophoblasts, secretory endometrial glands, and decidual cells of the stroma. Therefore, it appears that the immunohistochemical expression of p53 can occur in a variety of situations, including neoplastic, proliferative, and nonproliferative conditions. Although p53 mutations are often the basis of excessive accumulation of mutant p53 protein in malignancies, other mechanisms may be involved in nonneoplastic conditions. These findings emphasize the need for caution in the interpretation of immunohistochemical expression of p53 protein.

Constitutional trisomy 8 mosaicism and gestational trophoblastic disease

Concurrence of congenital trisomy 8 mosaicism and gestational trophoblastic disease in a 42-year-old gravida IV, para IV female is described in the present report. In contrast to other cases described in the literature, our patient had no known additional confounding chromosomal abnormalities other than trisomy 8. The finding of trisomy 8 mosaicism in yet another type of cancer provides further support for the hypothesis of an increased predisposition to cancer in tissues with constitutional genomic imbalance, which can manifest itself as numerical chromosomal abnormalities (e.g., trisomies) or structural chromosomal abnormalities (e.g., translocations). To the best of our knowledge, this is the only report in the English literature of constitutional trisomy 8 mosaicism associated with gestational trophoblastic disease, a rare gynecologic disease entity in itself.

Paternally derived H19 is differentially expressed in malignant and nonmalignant trophoblast

The paternal allele of the H19 gene has been shown to be transcriptionally inactive in the developing human embryo. Using reverse transcription PCR and RNase protection assays, we demonstrate that expression of H19 is predominantly, but not exclusively, from the maternal allele in the human placenta. In situ hybridization analysis shows strong expression of the H19 gene in eight complete hydatidiform moles, hyperplastic tissues consisting of trophoblasts which contain only paternally derived genetic material, indicating that H19 is not functionally imprinted in this tissue. H19, a putative growth suppressor, is oppositely imprinted to the neighboring insulin-like growth factor II (IGF2) gene and an up-regulation of IGF2 expression has been linked previously to a down-regulation of H19 expression in the progression to Wilms' tumor. Two cases of complete hydatidiform mole which progressed to choriocarcinoma show high levels of expression of both H19 and IGF2. The choriocarcinomas which developed from these complete hydatidiform moles showed similar expression of IGF2 but a decreased number of H19-positive cells, which may reflect selection for cells expressing IGF2 and against those expressing H19 in this tissue.