Matrix metalloproteinases and their inhibitors in gestational trophoblastic diseases and normal placenta.

OBJECTIVE: Our purpose was to investigate the expression of matrix metalloproteinases (MMPs) in gestational trophoblastic diseases and normal first-trimester placenta. METHODS: Paraffin sections of 16 partial moles, 25 complete moles, 10 gestational choriocarcinomas, and 11 normal first-trimester placentas were studied immunohistochemically for expression of MMP-1, MMP-2, MMP-3, MMP-9, MMP-13, and tissue inhibitor of metalloproteinase-1 (TIMP-1). RESULTS: Nine (90.0%) of the choriocarcinoma cases showed strong intensity of staining for MMP-1. Choriocarcinoma exhibited significantly stronger staining for MMP-1 than syncytiotrophoblast in normal placenta (P < 0.01), partial mole (P < 0.01), and complete mole (P < 0.01). Choriocarcinoma also showed significantly stronger staining for MMP-1 than the extravillous trophoblast in placenta (P < 0.05). MMP-2 was expressed only in syncytio- and extravillous trophoblasts in normal placenta, partial mole, and complete mole. Choriocarcinoma and the extravillous trophoblast in partial mole and complete mole had significantly stronger staining for MMP-2 than the extravillous trophoblast in placenta (P < 0.05, P < 0.01, P < 0.01, respectively). Choriocarcinoma also exhibited significantly stronger staining for MMP-2 than syncytiotrophoblasts in placenta (P < 0.01), partial mole (P = 0.05), and complete mole (P < 0.01). The expression of MMP-3, MMP-9, and MMP-13 was similar in all four tissues with the predominance of syncytiotrophoblast for MMP-3 and MMP-13 and cytotrophoblast for MMP-9. While 8 (73.0%) placentas, 14 (87.5%) partial moles, and 19 (76.0%) complete moles showed strong immunoreactivity for TIMP-1 in syncytiotrophoblasts, no strong staining was found in choriocarcinomas (P < 0.01, P < 0.01, P < 0.01, respectively). CONCLUSION: The extravillous trophoblast of first-trimester placenta has significantly less expression of MMP-1 than choriocarcinoma and significantly less expression of MMP-2 than choriocarcinoma and extravillous trophoblast of partial and complete mole. The expression of TIMP-1 was significantly less in choriocarcinoma than the syncytiotrophoblast of normal placenta, partial mole, and complete mole. MMPs and their inhibitors may play a role in the pathogenesis of gestational trophoblastic diseases.     

Molecular biology of gestational trophoblastic neoplasia: a review

Gestational trophoblastic diseases are interrelated conditions characterized by abnormal growth of chorionic tissues with varying propensitiesfor local invasion and metastases. These diseases are characterized by altered expression of several growth regulatory factors and oncogenes. On the basis of the expression of various oncogenes and growth factors, partial mole appears to be more like normal placenta, while complete mole seems to be more like choriocarcinoma. These results may have both prognostic and therapeutic consequences and provide insight into the relationship between normal placenta and gestational trophoblastic diseases.     

The relationship between expression of c-ras,c-erbB-2, nm23, and p53 gene products and development of trophoblastic tumor and their predictive significance for the malignant transformation of complete hydatidiform mole

OBJECTIVE: The aims of this retrospective study by means of immunohistochemical staining were (1) to study the expression of c-ras, c-erbB-2, p53, and nm23 gene products in complete hydatidiform moles that progress to gestational trophoblastic tumor and in those that remit spontaneously after evacuation, and (2) to estimate the predictive value of the expression of these four gene products in malignant transformation of complete hydatidiform mole. METHODS: Clinical data of patients with complete hydatidiform mole were obtained by retrospective chart review. Formalin-fixed paraffin sections of 50 cases of complete mole that progressed to gestational tumor and 32 cases of complete mole that remitted spontaneously were studied immunohistochemically for c-ras, c-erbB-2, p53, and nm23 proteins. The prognostic value of the proteins for the malignant transformation of complete mole was analyzed by multiple logistic regression and stepwise logistic estimation. Sections of 30 cases of invasive mole and 19 cases of choriocarcinoma were also immunohistologically studied for expression of the proteins. RESULTS: Expression of c-erbB-2 and p53 gene products was significantly increased and expression of nm23 and c-ras products was remarkably decreased in complete hydatidiform moles that progressed into postmolar tumor compared with those that remitted spontaneously after evacuation. There was no significant difference in the expression of the four genes in invasive mole and in choriocarcinoma. A logistic estimation model for predicting malignant transformation of complete mole was established based on the expression of gene products. When the expression of four gene products was used, the predictive sensitivity of the regression model was 86.0%, and the specificity was 75.0%. The positive predictive value was 84.3%, the negative predictive value was 77.4%. Logistic stepwise regression analysis showed that the altered expression of c-erbB-2 and nm23 products had strong predictive value, while the expression of c-ras and p53 products had no significant predictive value for the malignant transformation of complete mole. CONCLUSION: The altered expression of c-ras, c-erbB-2, nm23, and p53 gene products may be important in the pathogenesis of gestational trophoblastic tumor. The decreased expression of nm23 protein and increased expression of c-erbB-2 protein are strong predictors for the malignant transformation of complete mole.     

葡萄胎表皮生长因子受体表达与滋养细胞增生和葡萄胎恶变的相关性研究

目的 探讨表皮生长因子受体（EGFR）表达、滋养细胞增生与葡萄胎恶变的关系。方法 检测石蜡包埋的135例葡萄胎和13例正常早孕绒毛标本,常规组织切片病理观察滋养细胞增生程度,免疫组化法检测EGFR表达情况。结果EGFR在所有类型的滋养细胞和正常绒毛中表达。全部合体滋养层细胞的EGFR为强阳性。在细胞滋养层细胞,非恶变组葡萄胎EGFR阳性表达率与正常绒毛的阳性表达率无显著差异（P>0.05）,恶变组葡萄胎EGFR的阳性表达率显著低于正常绒毛和无恶变组葡萄胎（P<0.05,P<0.01）;轻度滋养细胞增生者EGFR阳性表达率显著强于中度及重度滋养细胞增生者（P<0.01,P<0.01）,中度与重度滋养细胞增生者EGFR表达无显著性差异（P>0.05）。结论 恶变组葡萄胎EGFR的表达弱于非恶变组葡萄胎,滋养细胞增生程度重者EGFR表达减少,EGFR表达降低在葡萄胎恶变过程中可能有重要的生物学意义。     

P63 expression in hydropic abortion and gestational trophoblastic diseases

Gestational trophoblastic diseases are a group of interrelated diseases of trophoblastic tissue that include partial hydatidiform mole, complete hydatidiform mole, invasive mole, choriocarcinoma, and placental site trophoblastic tumor. P63 is a p53 homologue that, in normal placentas, is expressed in the cytotrophoblast cells. The role of p63 in gestational trophoblastic diseases, however, merits further investigation. Immunohistochemistry with the p63 antibody (clone 4A4) was performed in formalin-fixed paraffin-embedded samples of hydropic abortion (n=10), partial hydatidiform mole (n=12), complete hydatidiform mole (n=12) and choriocarcinoma (n=5). P63 expression was quantitatively assessed as 0 (no stained cells), + (less than 10% positive cells), ++ (10-50% positive cells), and +++ (more than 50% positive cells). The intensity was scored as 0 (absence), + (weak), ++ (moderate), or +++ (strong). Statistical analysis was carried out by the Fisher test. In contrast to the other diagnoses, none of the choriocarcinomas analyzed exhibited p63-positive cells. There was no difference in distribution of p63 positive cells between hydropic abortion, partial hydatidiform mole, and complete hydatidiform mole. Concerning the intensity of immunostaining, there was difference only between partial hydatidiform mole and complete hydatidiform mole. According to our results, p63 might be useful to differentiate a choriocarcinoma from other gestational trophoblastic diseases. Besides, since the intensity of p63 expression was much stronger in partial hydatidiform mole and complete hydatidiform mole than in hydropic abortion, this feature may be helpful in distinguishing these two diagnoses in challenging cases.     

Current understandings of the molecular genetics of gestational trophoblastic diseases

Gestational trophoblastic disease (GTD) is a heterogeneous group of diseases characterized by abnormally proliferating trophoblastic tissues. This includes partial and complete hydatidiform moles, invasive mole, choriocarcinoma and placental site trophoblastic tumour. Cytogenetic studies revealed that hydatidiform moles contain either solely (as in complete moles) or an excess (as in partial moles) of paternal contribution to the genome. Genomic imprinting is believed to play a pivotal role in the pathogenesis of hydatidiform moles. However its precise role and mechanism remains poorly understood. Hydatidiform mole carries a potential of malignant transformation. Similar to other human cancers, malignant transformation in gestational trophoblastic tumours is likely a multistep process and involves multiple genetic alterations including activation of oncogenes and inactivation of tumour suppressor genes. In addition, expression of telomerase activity, altered expression of cell--cell adhesion molecules and abnormal expression of matrix metalloproteinases have also been reported in GTD. These represent disruption of the delicate balance and regulation of cellular processes including proliferation, differentiation, apoptosis and invasion. The significance of these alterations in the pathogenesis and malignant transformation of gestational trophoblastic diseases is reviewed in this paper.     

Expression of c-erb B-2 oncogene product in persistent gestational trophoblastic disease

OBJECTIVE: Much debate exists on the initiation of chemotherapy for women at risk for persistent gestational trophoblastic disease. This is a result of a lack of early predictors for the development of persistent gestational trophoblastic disease after evacuation of a complete hydatidiform mole, because the only current reliable method of detection and diagnosis lies in persistent or rising postmolar β-human chorionic gonadotropin values. We used immunocytochemical techniques to retrospectively study the expression of the c-erb B-2 oncogene product in formalin-fixed, paraffin-embedded trophoblastic tissues as a potential indicator of the development of persistent gestational trophoblastic disease. STUDY DESIGN: In this retrospective study 56 trophoblastic tumors were examined by means of immunocytochemical techniques to stain for the oncogene product for evidence of c-erb B-2 expression. Our 56 cases included original tissue from 20 cases of complete mole that progressed to persistent gestational trophoblastic disease, seven cases of choriocarcinoma after term pregnancy or abortion, and 29 cases of hydatidiform mole representing postevacuation, spontaneously regressing disease (including one partial mole). We also studied 11 cases of first-trimester trophoblast and 15 cases of term placenta as additional controls. RESULTS: Our results showed positive immunostaining for c-erb B-2 gene product in one case of persistent gestational trophoblastic disease, with negative staining in all other cases in the study groups and controls. CONCLUSION: Analysis for the significance of c-erb B-2 expression in persistent gestational trophoblastic disease showed that this correlation between c-erb B-2 expression and persistent gestational trophoblastic disease is not significant, suggesting that future efforts should be directed at the involvement of different oncoproteins. (AM J Obstet Gynecol 1994;170:1616-22.)     

Expression of the p53 gene and apoptosis in gestational trophoblastic disease

In order to understand the involvement of the p53 tumour suppressor gene in the pathogenesis of gestational trophoblastic disease (GTD), we investigated its genetic status, protein expression and its role in apoptosis in samples of complete and partial hydatidiform mole as compared with those of normal placenta. Direct sequencing of polymerase chain reaction (PCR) products of the coding and non-coding regions of the p53 gene demonstrated no mutations in any of the studied samples. Immunohistochemical studies revealed increased expression of the p53 protein predominantly in the nuclei of villous cytotrophoblasts. This over-expression of p53 was found in all samples of complete mole, in 50 per cent of partial mole samples and in about 30 per cent of normal placenta cases, although no significant difference in the staining intensity and pattern was observed. An in situ detection of DNA nicking (TUNEL) staining, demonstrating apoptosis, was also detected predominantly in villous cytotrophoblasts and in stromal areas. The per centage of apoptotic cells in all studied samples, determined by flow cytometry, demonstrated a significant increase in apoptotic cells in samples of complete and partial hydatidiform mole compared with those of normal placenta (P< 0.0003 and P< 0.004, respectively).In conclusion, the current study may provide a possible explanation to the pathogenesis of GTD, probably associated with extensive p53-dependent apoptosis to modulate excessive trophoblastic proliferation.     

Differential distribution of placental leucine aminopeptidase/oxytocinase and aminopeptidase A in human trophoblasts of normal placenta and complete hydatidiform mole

Placental leucine aminopeptidase (P-LAP)/oxytocinase (OTase) degrades several small peptides such as oxytocin (OT), arginine vasopressin (AVP) and angiotensin III (ANGIII), and aminopeptidase A (AP-A) converts angiotensin II (ANGII) to ANGIII. These proteases play an important role in foetal growth and the maintenance of human homeostasis during pregnancy. In this study, we confirmed the distribution of P-LAP and AP-A proteins and messenger RNAs in human trophoblasts in normal placenta and complete hydatidiform mole by immunohistochemical and in-situ hybridization techniques. Immunoreactivity of P-LAP was mainly noted in the apical membrane of syncytiotrophoblasts, and the expression of messenger RNA (mRNA) for P-LAP was predominantly noted in the cytoplasm of syncytiotrophoblastic cells. However, immunoreactivity of AP-A was mainly noted in the apical membrane of cytotrophoblasts and in the basal zone of the syncytiotrophoblasts, and the expression of mRNA for AP-A was predominantly noted in cytoplasm of cytotrophoblastic cells and a little in cytoplasm of syncytiotrophoblastic cells. Thereby, the two proteases were differentially distributed both in normal placenta and hydatidiform mole throughout the gestational age. These results are useful for the further understanding of not only the pathophysiology of pregnancy, but also the pathogenesis of trophoblastic diseases.     

Levels of placenta growth factor in gestational trophoblastic diseases

OBJECTIVE: The aim of the current study was to investigate levels of placenta growth factor in the tissues and sera of the patients with gestational trophoblastic disease and to determine its usefulness for the treatment of gestational trophoblastic disease. STUDY DESIGN: Placenta growth factor concentrations were measured in the tissue homogenates of 12 normal placentas, 33 complete hydatidiform moles, and 6 gestational choriocarcinomas. Serum placenta growth factor levels were determined in 59 women with normal pregnant course, in 30 women with complete hydatidiform mole, in 36 women with persistent gestational trophoblastic disease, and 100 nonpregnant healthy volunteers. RESULTS: Serum and tissue placenta growth factor levels in the patients with mole tended to be decreased compared with the levels in normal pregnancy; the levels were increased significantly in patients with choriocarcinoma. When serum placenta growth factor levels were >20 pg/mL (normal upper limit in nonpregnant women), placenta growth factor-to-human chorionic gonadotropin ratios were increased significantly in patients with persistent gestational trophoblastic disease. CONCLUSION: Serum placenta growth factor levels are not of any predictive value in patients with hydatidiform mole. However, elevated serum placenta growth factor levels with increased placenta growth factor-to-human chorionic gonadotropin ratios are suggestive of persistent gestational trophoblastic disease.     

Recent advances in molecular biology of gestational trophoblastic diseases. A review

Gestational trophoblastic diseases are interrelated conditions characterized by abnormal growth of chorionic tissues with various propensities for local invasion and metastasis. Complete mole is a unique conception in that all nuclear DNA is paternally derived and all cytoplasmic DNA is maternally derived. In contrast, partial mole generally has a triploid karyotype, where the extra haploid set of chromosomes is paternally derived: Gestational trophoblastic diseases are characterized by altered expression of several growth regulatory factors and oncogenes. While differences in expression of oncoproteins may be important to the development of gestational trophoblastic disease, the precise molecular changes that are critical to pathogenesis remain unknown.     

Expression of nm23-H1 in hydatidiform mole and its relationship with the development of postmolar disease.

The aim of the present study was to investigate the expression of nm23-H1 in human placenta, hydatidiform mole and choriocarcinoma cells. Nm23-H1 protein was localized in the cytotrophoblast, but not in the syncytiotrophoblast. In the hydatidiform mole cases with subsequent spontaneous remission, nm23-H1 mRNA levels were significantly lower than those in first-trimester placentas. However, its levels were elevated in the hydatidiform mole cases that progressed to persistent gestational trophoblastic disease and were comparable to those of first-trimester placentas, and they were further elevated in choriocarcinoma cells. The present data suggest an association of nm23-H1 for the proliferation activity of trophoblast, and its increased expression may influence the development of persistent trophoblastic disease.     

Demonstration of TGF-α–EGFR and EGF-EGFR autocrine loops and their relation to proliferation in complete hydatidiform moles (CHM)

Abstract. Balaram P, John M, Enose S, Symaladevi PK. TGF-α–EGFR and EGF-EGFR autocrine loops and their relation to proliferation in complete hydatidiform moles (CHM).
Complete hydatidiform moles (CHM) are the most common form of gestational trophoblastic disease. The prevalence rate is much higher in the state of Kerala, India, than in other parts of the world. The biology and role of growth factors are not fully understood in these tumors. In this study, we have immunohistochemically evaluated the expression of epidermal growth factor (EGF) and transforming growth factor alpha (TGF-α) along with their receptor, epidermal growth factor receptor (EGFR), and we have related them to the proliferative activity in normal placenta and CHM using the expression of proliferating cell nuclear antigen (PCNA) as the marker of proliferation. The results suggest activation of both EGF-EGFR and TGF-α–EGFR autocrine pathways in both types of tissues, with a predominance of the TGF-α–EGFR autocrine pathway in CHM. This is especially so in the more aggressive cases of CHM, the persisting group of diseases.     

Outcome of Pregnancies Occurring before Completion of Human Chorionic Gonadotropin Follow-Up in Patients with Persistent Gestational Trophoblastic Tumor

OBJECTIVE: To determine the outcome of pregnancies occurring before completion of human chorionic gonadotropin follow-up in patients treated with chemotherapy for gestational trophoblastic tumor. METHODS: Retrospective record review of patients with gestational trophoblastic tumor who conceived before standard hCG follow-up was completed during 1973-1998. RESULTS: Forty-three patients treated for gestational trophoblastic tumors conceived before human chorionic gonadotropin follow-up was completed. The antecedent pregnancy was complete mole in 31 (72.1%) and partial mole in 12 (27. 9%) patients. Of the 43 patients, 39 (90.7%) had stage I, 1 had stage II, and 3 had stage III disease. The mean interval from human chorionic gonadotropin remission to new pregnancy was 6.3 months (range 1-11 months). Ten patients underwent elective termination and four patients were lost to follow-up. Of the remaining 29 patients, 22 (75.9%) had term live births, 3 (10.3%) had preterm delivery, 3 had spontaneous abortion, and 1 (3.5%) had a repeat mole. Two cases of fetal anomalies were detected; one was inherited polydactyly and the other was hydronephrosis. One patient developed choriocarcinoma with lung involvement and underwent cesarean section at 28 weeks; a normal fetus was delivered and no choriocarcinoma was detected in the placenta. CONCLUSION: Pregnancies occurring in patients treated for gestational trophoblastic tumor before standard human chorionic gonadotropin follow-up is completed may continue under close clinical surveillance since the majority have a favorable outcome. However, patients should also be advised of the low but important risk of delayed diagnosis in case tumor relapse develops during early subsequent pregnancy.     

Correlation of c-erbB-2 oncogene and p53 tumor suppressor gene with malignant transformation of hydatidiform mole

AIM: Considering the roles of c-erB-2 and p53 oncoproteins in tumor progression, we aimed to evaluate their expression in hydatidiform moles, and the possible predictive value of this immunoexpression in postmolar follow-up. METHODS: Group I comprised 35 patients with progression to gestational trophoblastic tumor, and group II included 32 patients with progression to spontaneous remission. Immunohistochemical tests were performed by streptavidin-peroxidase method. c-erbB-2 immunoexpression was evaluated according to quantitative and semiquantitative criteria; p53 according to percentage of cells with stained nuclei. Data were analyzed by Student t-test, Mann-Whitney test, ROC curve and logistic regression analysis. RESULTS: c-erbB-2 and p-53 expressions were significantly increased in group I. Quantitative and semiquantitative analysis of c-erb-2 showed that its expression may be associated with mole hydatidiform progression to gestational trophoblastic tumor. Taking into account cells with complete membranous delineation we proposed a cut-off value of 10.8%. Similarly, considering the percentage of cells presenting nuclei marked by p53 we suggested a cut-off value of 40.1% for the prediction of malignant transformation of mole hydatidiform. CONCLUSIONS: c-erbB-2 and p53 immunoexpression in hydatidiform mole are usually increased with malignant transformation. In addition to beta-fraction of human chorionic gonadotropin, they could possibly help the establishment of a therapeutic protocol.     

Pathology of gestational trophoblastic diseases

Gestational trophoblastic disease (GTD) is a heterogeneous group of diseases. This used to include partial and complete hydatidiform moles, invasive mole, choriocarcinoma and placental site trophoblastic tumour. In recent years, new entities, including epithelioid trophoblastic tumour, have been added to this family. Non-neoplastic and neoplastic lesions derived from implantation site and chorion intermediate trophoblast have been gaining attention in the literature. New markers for trophoblasts have been identified facilitating histological diagnosis in cases with unusual clinical or pathological features. It is worth noting that histological distinction between hydropic abortion and partial mole and between complete and partial moles, especially at early gestational age, may be difficult. It may not be possible to predict progress of the heterogeneous group of GTD from histopathological features, except probably in placental site trophoblastic tumour. Alternative biological markers may be explored for better patient management.     

Ancillary Techniques to Refine Diagnosis of GTD

Gestational trophoblastic disease (GTD) consists of hyperplastic and neoplastic disorders of placental trophoblast; i.e., hydatidiform moles and gestational trophoblastic tumors, respectively. While the histological diagnosis of well-developed complete hydatidiform mole and gestational choriocarcinoma is generally accurate, significant diagnostic challenges persist in the routine evaluation of early complete hydatidiform mole, partial hydatidiform mole, placental site trophoblastic tumor, and epithelioid trophoblastic tumor. Recently, the applications of new immunohistochemical markers and molecular techniques have significantly enhanced the diagnostic accuracy of various GTDs. P57 immunohistochemistry is a highly useful marker in confirming complete hydatidiform mole, including its early forms. PCR-based short tandem repeat DNA genotyping has emerged as a powerful diagnostic measure to precisely classify both complete and partial hydatidiform moles. With highly desired sensitivity and specificity, these powerful ancillary studies should be advocated and integrated into the routine diagnostic algorithm of GTD.     

Altered imprinting,promoter usage,and expression of insulin-like growth factor-II gene in gestational trophoblastic diseases

OBJECTIVE: We aimed to understand the involvement of imprinted genes in the pathogenesis of gestational trophoblastic diseases (GTD) such as hydatidiform mole (H-mole) and gestational trophoblastic tumors (GTT). METHODS: An allelic-typing assay was performed using a PCR-RFLP-based method for identification of heterozygous informative cases. The usage of insulin-like growth factor-II (IGF2) promoters was examined by RT-PCR using promoter-specific primers. The mRNA expression of IGF2 and H19 was quantified using a densitometer. RESULTS: The imprinting of IGF2 and H19 was maintained in all normal placenta tissues (n = 15) but relaxed in GTD (n = 47). Loss of imprinting (LOI) of IGF2 was in the order of GTT (57%) > complete H-mole (43%) > partial H-mole (25%). Similarly, LOI of H19 was in the order of GTT (40%) > complete H-mole (18%) > partial H-mole (0%). Promoter usage pattern of IGF2 changed with gestation stage of normal placentae and GTD. In normal placentae, the usage of promoter P1 was higher than that of P4 in the first trimester but lowered in the full term. H-mole and GTT predominantly used promoter P1 with relative silencing of promoter P4. Although normal early placenta and various GTD tissues showed the similar usage of IGF2 promoter P1, GTT tissues revealed the higher expression levels of IGF2 but a down-regulation of H19 relative to the normal early placentae. CONCLUSIONS: These results suggest that LOI, deregulation of IGF2 promoters, and the altered expression levels of IGF2 and H19 genes might be associated with the progression of GTD.