Levels of placenta growth factor in gestational trophoblastic diseases

Serum angiogenesis profile in gestational trophoblastic neoplasm using multiplex immunoassay

AIMS

Gestational trophoblastic neoplasms (GTN) exemplify a rare, mostly curable but highly aggressive disease. It is often associated with a rapid formation of distant metastases and most likely with an intense neoangiogenesis processes. The aim of the study was to analyze markers in serum of patients with GTN before chemotherapy compared to healthy pregnant women.

MAIN METHODS

In this study sixteen protein angiogenesis markers were evaluated in serum of 21 patients with GTN before chemotherapy and compared with healthy pregnant women. Markers were measured using BioPlex Pro Human Cancer Biomarker Panel 1 immunoassay. t-Tests and receiver operating characteristic curves were used for statistical analysis.

KEY FINDINGS

Receiver operator curve analysis identified six proteins (sTIE-2, osteopontin, sIL-6α, sVEGFR-2, sEGFR, PECAM-1) which had sufficient sensitivity and specificity (AUC > 0,70) to distinguish GTN patients before the treatment from pregnant controls. The levels of three proteins (sTIE-2, osteopontin and sIL-6α) were altered in GTN patients before the treatment as compared to healthy controls (p = 0,0112; p = 0,0442; p = 0,0488, respectively) and thereby may serve as potential disease markers.

SIGNIFICANCE

Serum concentration of proteins related to angiogenesis changes in the course of GTN and may appear useful in the diagnostic process of this disease.

The predictive value of the sFlt-1/PlGF ratio on short-term absence of preeclampsia and maternal and fetal or neonatal complications in twin pregnancies

OBJECTIVE

A sFlt-1/PlGF ratio of ≤38 has been reported to predict the absence of preeclampsia (PE) in singleton pregnancies. We evaluated whether a sFlt-1/PlGF ratio of ≤38 could be used to predict the absence of PE in twin pregnancies and maternal and fetal/neonatal complications.

METHODS

This is a secondary analysis of a prospective multicenter cohort study that enrolled women with suspected or confirmed PE with the aim of evaluating the use of the sFlt-1, PlGF and their ratio to predict maternal and fetal/neonatal complications. Twin and singleton pregnancies with clinically suspected or confirmed PE were matched for gestational age and parity. Blood samples were drawn at time of study entry, but serum values of sFlt-1 and PlGF and their ratio were determined postpartum.

RESULTS

Twenty-one women with twin and 21 with singleton gestations were included at a median gestational age of 30 weeks. At inclusion PE was diagnosed in 13 twin and 15 singleton pregnancies. In comparison to singleton control pregnancies, twin controls had a significantly higher sFlt-1 (6377 vs. 1732 pg/ml, p = 0.008), a higher sFlt-1/PlGF ratio 26 vs. 3 p = 0.361) and a lower PlGF (228 vs. 440 pg/ml p = 0.479). Compared to singleton preeclamptic pregnancies values of sFlt-1 (9134 vs. 8625 pg/ml) did not differ, whereas values of PlGF (185 vs. 33 pg/ml, p < 0.001) were higher and values of the ratio (49 vs. 158, p = 0.002) were lower in preeclamptic twin pregnancies. All preeclamptic patients with a singleton pregnancy had a ratio >38, but only 5 of the 13 patients with a preeclamptic twin pregnancy. Conversely, the ratio was ≤38 in 5 of the 6 control singleton, but in only 4 of the 8 control twin pregnancies. When classified according to a ratio ≤38 or >38 at inclusion, maternal complications occurred more frequently in patients with a ratio >38 both in singleton and twin pregnancies. In singleton pregnancies fetal/neonatal complications, except one admission to NICU, only occurred in patients with a ratio >38. In twin pregnancies fetal/neonatal complications occurred equally frequent in women with a ratio ≤38 or >38.

CONCLUSION

Serum sFlt-1 levels are considerably higher in twin than in singleton control gestations. A sFlt-1/PlGF ratio of ≤38 to predict short-term absence of PE is not applicable to twin pregnancies in predicting either the absence of PE or the absence of adverse pregnancy outcomes.

[Potential role of the angiogenic factor "EG-VEGF" in gestational trophoblastic diseases]

Gestational trophoblastic disease (MGT) includes a wide spectrum of pathologies of the placenta, ranging from benign precancerous lesions, with gestational trophoblastic tumors. Metastases are the leading causes of death as a result of this tumor. They represent a major problem for obstetrics and for the public health system. To date, there is no predictor of the progression of molar pregnancies to gestational trophoblastic tumor (GTT). Only an unfavorable plasma hCG monitoring after evacuation of hydatidiform mole is used to diagnose a TTG. The causes of the development of this cancer are still poorly understood. Increasing data in the literature suggests a close association between the development of this tumor and poor placental vascularization during the first trimester of pregnancy. The development of the human placenta depends on a coordination between the trophoblast and endothelial cells. A disruption in the expression of angiogenic factors could contribute to uterine or extra-uterine tissue invasion by extravillous trophoblast, contributing to the development of TTG. This review sheds lights on the phenomenon of angiogenesis during normal and abnormal placentation, especially during the MGT and reports preliminary finding concerning, the variability of expression of "Endocrine Gland-Derived Vascular Endothelial Growth Factor" (EG-VEGF), a specific placental angiogenic factor, in normal and molar placentas, and the potential role of differentiated expressions of the main placental angiogenic factors in the scalability of hydatidiform moles towards a recovery or towards the development of gestational trophoblastic tumor. Deciphering the mechanisms by which the angiogenic factor influences these processes will help understand the pathophysiology of MGT and to create opportunities for early diagnosis and treatment of the latter.

Targeted therapies for rare gynaecological cancers

Some gynaecological cancers are uncommon, such as sex cord-stromal tumours, malignant germ-cell tumours, vulvar carcinoma, melanoma of the female genital tract, clear-cell carcinoma of the ovary and endometrium, neuroendocrine tumours of the cervix, and gestational trophoblastic neoplasia. All these cancers have different clinicopathological characteristics, suggesting different molecular biological pathogeneses. Despite aggressive treatment, some cancers recur or respond poorly to therapy. Comprehensive knowledge of the molecular biology of each cancer might help with development of novel treatments that maximise efficacy and minimise toxic effects. Targeted therapy is a new treatment strategy that has been investigated in various tumours in clinical and laboratory settings. Since these cancers are rare and large clinical trials are difficult to do, molecular biological techniques might allow rapid proof-of-principle experiments in few patients. Novel targeted agents either alone or in combination with other treatments offer promising therapeutic options.

Angiogenesis in gynecological oncology-mechanism of tumor progression and therapeutic targets

The purpose of this article is to review the current literature pertaining to various angiogenic stimulators and angiogenesis inhibitors in gynecological malignancies and the relevance of these markers in the prognosis of these diseases. We also summarize the antiangiogenic drugs currently in development and in clinical use in gynecological oncology. The information was obtained from a computer search of MEDLINE for studies published in the English language regarding angiogenesis and angiogenesis inhibitors in gynecological malignancies between 1970 and December 2003; additional sources were identified through cross-referencing. In ovarian cancer, various different angiogenic activators have been found to correlate with microvessed density (MVD), stage, lymph node and peritoneal metastasis, and survival. In cervical cancer, correlation has been seen between increased angiogenic markers and stage, grade, tumor size, and survival. Studies in endometriat cancer show correlation of angiogenic markers with stage, grade, MVD, and survival. Whereas, in gestational trophoblastic neoplasm (GTD) only few markers have been studied, and some correlated with progression. Information on anti angiogenic drugs currently in ongoing and upcoming trials in gynecological malignancies is also presented. Angiogenesis factors may have a prognostic role to play in patients with gynecological cancers and should continue to be investigated as clinically useful tumor markers. Antiangiogenic-targeted therapies offer an attractive strategy for clinical investigation in gynecologic oncology.

Model of competitive binding of vascular endothelial growth factor and placental growth factor to VEGF receptors on endothelial cells

Placental growth factor (PlGF) competes with vascular endothelial growth factor (VEGF) for binding to VEGF receptor (VEGFR)-1 but does not bind VEGFR2. Experiments show that PlGF can augment the response to VEGF in pathological angiogenesis and in models of endothelial cell survival, migration, and proliferation. This synergy has been hypothesized to be due to a combination of the following: signaling by PlGF through VEGFR1 and displacement of VEGF from VEGFR1 to VEGFR2 by PlGF, causing increased signaling through VEGFR2. In this study, the relative contribution of PlGF-induced VEGF displacement to the synergy is quantified using a mathematical model of ligand-receptor binding to examine the effect on ligand-receptor complex formation of VEGF and PlGF acting together. Parameters specific to the VEGF-PlGF system are used based on existing data. The model is used to simulate in silico a specific in vitro experiment in which VEGF-PlGF synergy is observed. We show that, whereas a significant change in the formation of endothelial surface growth factor-VEGFR1 complexes is predicted in the presence of PlGF, the increase in the number of VEGFR2-containing signaling complexes is less significant; these results were shown to be robust to significant variation in the kinetic parameters of the model. Synergistic effects observed in that experiment thus appear unlikely to be due to VEGF displacement but to a shift from VEGF-VEGFR1 to PlGF-VEGFR1 complexes and an increase in total VEGFR1 complexes. These results suggest that VEGFR1 signaling can be functional in adult-derived endothelial cells.