A splice acceptor variant in RGS6 associated with intellectual disability, microcephaly, and cataracts disproportionately promotes expression of a subset of RGS6 isoforms

Intellectual disability (ID) is associated with an increased risk of developing psychiatric disorders, suggesting a common underlying genetic factor. Importantly, altered signaling and/or expression of regulator of G protein signaling 6 (RGS6) is associated with ID and numerous psychiatric disorders. RGS6 is highly conserved and undergoes complex alternative mRNA splicing producing ~36 protein isoforms with high sequence similarity historically necessitating a global approach in functional studies. However, our recent analysis in mice revealed RGS6 is most highly expressed in CNS with RGS6L(+GGL) isoforms predominating. A previously reported genetic variant in intron 17 of RGS6 (c.1369-1G>C), associated with ID, may provide further clues into RGS6L(+GGL) isoform functional delineation. This variant was predicted to alter a highly conserved canonical 3' acceptor site creating an alternative branch point within exon 18 (included in a subset of RGS6L(+GGL) transcripts) and a frameshift forming an early stop codon. We previously identified this alternative splice site and demonstrated its use generates RGS6Lζ(+GGL) isoforms. Here, we show that the c.1369-1G>C variant disrupts the canonical, preferred (>90%) intron 17 splice site and leads to the exclusive use of the alternate exon 18 splice site, inducing disproportionate expression of a subset of isoforms, particularly RGS6Lζ(+GGL). Furthermore, RGS6 global knockout mice do not exhibit ID. Thus, ID caused by the c.1369-1G>C variant likely results from altered RGS6 isoform expression, rather than RGS6 isoform loss. In summary, these studies highlight the importance of proper RGS6 splicing and identify a previously unrecognized role of G protein signaling in ID.

Genetics of gestational trophoblastic disease

The abnormal pregnancies complete and partial hydatidiform mole are genetically unusual, being associated with two copies of the paternal genome. Typical complete hydatidiform moles (CHMs) are diploid and androgenetic, while partial hydatidiform moles (PHMs) are diandric triploids. While diagnosis can usually be made on the basis of morphology, ancillary techniques that exploit their unusual genetic origin can be used to facilitate diagnosis. Genotyping and p57 immunostaining are now routinely used in the differential diagnosis of complete and partial hydatidiform moles, for investigating unusual mosaic or chimeric products of conception with a molar component and identifying the rare diploid, biparental HMs associated with an inherited predisposition to molar pregnancies. Genotyping also plays an important role in the differential diagnosis of gestational and non-gestational trophoblastic tumours and identification of the causative pregnancy where tumours are gestational. Recent developments include the use of cell-free DNA for non-invasive diagnosis of these conditions.

Demographics, natural history and treatment outcomes of non-molar gestational choriocarcinoma: a UK population study

OBJECTIVE

To investigate the demographics, natural history and treatment outcomes of non-molar gestational choriocarcinoma.

DESIGN

A retrospective national population-based study.

SETTING

UK 1995-2015.

POPULATION

A total of 234 women with a diagnosis of gestational choriocarcinoma, in the absence of a prior molar pregnancy, managed at the UKs two gestational trophoblast centres in London and Sheffield.

METHODS

Retrospective review of the patient's demographic and clinical data. Comparison with contemporary UK birth and pregnancy statistics.

MAIN OUTCOMES

Incidence statistics for non-molar choriocarcinoma across the maternal age groups. Cure rates for patients by FIGO prognostic score group.

RESULTS

Over the 21-year study period, there were 234 cases of non-molar gestational choriocarcinoma, giving an incidence of 1:66 775 relative to live births and 1:84 226 to viable pregnancies. For women aged under 20, the incidence relative to viable pregnancies was 1:223 494, for ages 30-34, 1:80 227, and for ages 40-45, 1:41 718. Treatment outcomes indicated an overall 94.4% cure rate. Divided by FIGO prognostic groups, the cure rates were low-risk group 100%, high-risk group 96% and ultra-high-risk group 80.5%.

CONCLUSIONS

Non-molar gestational choriocarcinoma is a very rare diagnosis with little prior detailed information on the demographics and natural history. The data in this study give age-related incidence data based on a large national population study. The results also demonstrated the widely varying natural history of this rare malignancy and the marked correlation of disease incidence with rising maternal age.

TWEETABLE ABSTRACT

National gestational choriocarcinoma database indicates a close association between increasing maternal age and incidence.

ABC-transporter upregulation mediates resistance to the CDK7 inhibitors THZ1 and ICEC0942

The CDK7 inhibitors (CDK7i) ICEC0942 and THZ1, are promising new cancer therapeutics. Resistance to targeted drugs frequently compromises cancer treatment. We sought to identify mechanisms by which cancer cells may become resistant to CDK7i. Resistant lines were established through continuous drug selection. ABC-transporter copy number, expression and activity were examined using real-time PCR, immunoblotting and flow cytometry. Drug responses were measured using growth assays. ABCB1 was upregulated in ICEC0942-resistant cells and there was cross-resistance to THZ1. THZ1-resistant cells upregulated ABCG2 but remained sensitive to ICEC0942. Drug resistance in both cell lines was reversible upon inhibition of ABC-transporters. CDK7i response was altered in adriamycin- and mitoxantrone-resistant cell lines demonstrating ABC-transporter upregulation. ABCB1 expression correlated with ICEC0942 and THZ1 response, and ABCG2 expression with THZ2 response, in a panel of cancer cell lines. We have identified ABCB1 upregulation as a common mechanism of resistance to ICEC0942 and THZ1, and confirmed that ABCG2 upregulation is a mechanism of resistance to THZ1. The identification of potential mechanisms of CDK7i resistance and differences in susceptibility of ICEC0942 and THZ1 to ABC-transporters, may help guide their future clinical use.

A case of intraplacental gestational choriocarcinoma; characterised by the methylation pattern of the early placenta and an absence of driver mutations

Background

Gestational choriocarcinoma is a rare malignancy believed to arise from the trophoblast cells of the placenta. Despite the frequently aggressive clinical nature, choriocarcinoma has been routinely curable with cytotoxic chemotherapy for over 50 years. To date little is known regarding the route to oncogenesis in this malignancy.

Methods

In a case of intraplacental choriocarcinoma, we have performed detailed genetic studies including microsatellite analysis, whole genome sequencing (WGS) and methylation analysis of the tumour and surrounding mature placenta.

Results

The results of the WGS sequencing indicated a very low level of mutation and the absence of any driver mutations or oncogene activity in the tumour. The methylation analysis identified a distinctly different profile in the tumour from that of the mature placenta. Comparison with a panel of reference methylation profiles from different stages of placental development indicated that the tumour segregated with the first trimester samples.

Conclusions

These findings suggest that gestational choriocarcinoma is likely to arise as a result of aberrations of methylation during development, rather than from DNA mutations.

The results support the hypothesis that gestational choriocarcinoma arises from a normally transient early trophoblast cell. At this point in development this cell naturally has a phenotype of rapid division, tissue invasion and sensitivity to DNA damaging chemotherapy that is very similar to that of the mature choriocarcinoma cell.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5906-8) contains supplementary material, which is available to authorized users.

The results of treatment with high-dose chemotherapy and peripheral blood stem cell support for gestational trophoblastic neoplasia

OBJECTIVE

The objective of the study was to evaluate the effect of high-dose chemotherapy (HDC) with peripheral blood stem cell support (PBSCS) on survival of patients with gestational trophoblastic neoplasia (GTN) with either refractory choriocarcinomas or a poor-prognosis placental site/epithelioid trophoblastic tumours (PSTT/ETTs).

METHODS

Databases of two referral centres for gestational trophoblastic disease were searched, and 32 patients treated with HDC between 1994 and 2015 were identified. Tissue samples were retrieved for genetic evaluation. Cox regression analyses were performed to identify possible predictors of overall survival (OS).

RESULTS

HDC induced a sustained complete response in 7 patients. Overall, 41% (13/32) of the patients remained disease free after HDC with or without additional treatment. Patients who survived had much lower human chorionic gonadotropin (hCG) values (all ≤12 IU/L) before and after HDC than those who died of disease. Univariable Cox regression analysis demonstrated that hCG >12 IU/L before or after HDC, International Federation of Gynaecology and Obstetrics (FIGO) stage II-IV and presence of metastases at the time of diagnosis were significantly associated with adverse OS. However, only hCG values before HDC remained significant in a multivariable model (p < 0.001). Five of 11 (45%) patients with PSTT/ETT presenting ≥48 months after antecedent pregnancy and 6 of 14 (43%) patients with refractory choriocarcinoma were in remission. Three treatment-related deaths occurred.

CONCLUSIONS

Despite 3 treatment-induced deaths, HDC with PBSCS appears to be active in salvaging selected patients with poor-prognosis PSTT/ETTs and refractory choriocarcinomas. Low hCG values before HDC seems a beneficial predictor of OS and may suggest that HDC acts more like a consolidation therapy.

Diploid/triploid mixoploidy: A consequence of asymmetric zygotic segregation of parental genomes

Triploidy is the presence of an extra haploid set of chromosomes and can exist in complete or mosaic form. The extra haploid set of chromosomes in triploid cells can be of maternal or paternal origin. Diploid/triploid mixoploidy is a unique form of triploid mosaicism that requires the aberrant segregation of entire parental genomes into distinct blastomere lineages (heterogoneic cell division) at the earliest zygotic divisions. Here we report on eight cases of diploid/triploid mixoploidy from our institution and conduct a comprehensive review of the literature. The parental origin of the extra set of chromosomes was determined in two cases; and, based on phenotypic evidence we propose the parental origin in the other cases. One case with complex mixoploidy appears to have a digynic origin in addition to the involvement of two different sperm. Of our eight cases, only one resulted in the birth of a live healthy child. The other pregnancies ended in miscarriage, elective termination of pregnancy, intrauterine fetal demise or neonatal death. A review of the literature and the results of our cases show that a preponderance of recognized cases of diploid/triploid mixoploidy has a digynic origin.

Psychological Outcomes of Living Liver Donors From a Multicenter Prospective Study: Results From the Adult-to-Adult Living Donor Liver Transplantation Cohort Study2 (A2ALL-2)

Although single-center and cross-sectional studies have suggested a modest impact of liver donation on donor psychological well-being, few studies have assessed these outcomes prospectively among a large cohort. We conducted one of the largest, prospective, multicenter studies of psychological outcomes in living liver donors within the Adult-to-Adult Living Donor Liver Transplantation Cohort Study2 (A2ALL-2) consortium. In total, 271 (91%) of 297 eligible donors were interviewed at least once before donation and at 3, 6, 12, and 24 mo after donation using validated measures. We found that living liver donors reported low rates of major depressive (0-3%), alcohol abuse (2-5%), and anxiety syndromes (2-3%) at any given assessment in their first 2 years after donation. Between 4.7% and 9.6% of donors reported impaired mental well-being at various time points. We identified significant predictors for donors' perceptions of being better people and experiencing psychological growth following donation, including age, sex, relationship to recipient, ambivalence and motivation regarding donation, and feeling that donation would make life more worthwhile. Our results highlight the need for close psychosocial monitoring for those donors whose recipients died (n=27); some of those donors experienced guilt and concerns about responsibility. Careful screening and targeted, data-driven follow-up hold promise for optimizing psychological outcomes following this procedure for potentially vulnerable donors.

A national audit of colonic interposition for esophageal replacement

Esophageal replacement by colonic interposition is an uncommon procedure. This study sought to identify the frequency of this operation in England, identify techniques and associated problems, and also assess health-related quality of life (HR QOL) from the two largest centers performing this procedure. Hospital Episode Statistics were used to identify patients and centers undertaking colon interposition between March 2001 and March 2015. An online survey of UK consultants discussed methods and experience. HR QOL was assessed using the Short Form 36(SF-36v2) with additional gastrointestinal questions. Hospital Episode Statistics identified 328 interpositions (22 in pediatric hospitals). The two highest volume units did 42 and 45 operations, respectively. Thirty-four surgeons (79% response rate) replied to the survey. Fifty-two percent preferred to use the left colon with 81% preferring a substernal placement. The HR QOL survey was performed on 24 patients with a median of 3 years after surgery (ranging from 9 months to 10 years) from the two largest centers and a 56% response rate. Five patients had physical QOL scores above population average and 10 had mental scores above population average. All patients had early satiety, 20 described dysphagia, and 18 regularly took antireflux medication. There was an estimated mean loss of 13.1% body weight (10.6 kg) postoperatively and three patients still relied on a feeding tube for nutrition after an average of 3 years. Colon interposition results in an acceptable long-term QOL. Few centers regularly perform this operation, and centralizing to high-volume centers may lead to better outcomes.

Social and Financial Outcomes of Living Liver Donation: A Prospective Investigation Within the Adult-to-Adult Living Donor Liver Transplantation Cohort Study 2 (A2ALL-2)

Because results from single-center (mostly kidney) donor studies demonstrate interpersonal relationship and financial strains for some donors, we conducted a liver donor study involving nine centers within the Adult-to-Adult Living Donor Liver Transplantation Cohort Study 2 (A2ALL-2) consortium. Among other initiatives, A2ALL-2 examined the nature of these outcomes following donation. Using validated measures, donors were prospectively surveyed before donation and at 3, 6, 12, and 24 mo after donation. Repeated-measures regression models were used to examine social relationship and financial outcomes over time and to identify relevant predictors. Of 297 eligible donors, 271 (91%) consented and were interviewed at least once. Relationship changes were positive overall across postdonation time points, with nearly one-third reporting improved donor family and spousal or partner relationships and >50% reporting improved recipient relationships. The majority of donors, however, reported cumulative out-of-pocket medical and nonmedical expenses, which were judged burdensome by 44% of donors. Lower income predicted burdensome donation costs. Those who anticipated financial concerns and who held nonprofessional positions before donation were more likely to experience adverse financial outcomes. These data support the need for initiatives to reduce financial burden.

Abnormal villous morphology mimicking a hydatidiform mole associated with paternal trisomy of chromosomes 3,7,8 and unipaternal disomy of chromosome 11

Background

Pregnancies affected by non-molar chromosomal abnormality may sometimes demonstrate abnormal chorionic villous morphology that is similar to partial hydatidiform mole. Determination of the underlying aetiology may be difficult in such cases.

Case Presentation

This report describes a case referred to the regional trophoblastic disease unit as a possible hydatidiform mole that demonstrated both villous dysmorphology and abnormal p57^KIP2 expression. Molecular genotyping revealed that while most chromosomes in the villous tissue were diploid and biparental, chromosomes 3, 7 and 8 were trisomic with an additional paternally derived chromosome. In contrast chromosome 11 showed uniparental disomy of paternal origin a situation more usually associated with complete hydatidiform moles. This unusual case highlights that exceptions may occur to the general rules of both histological morphology and immunoprofile, and that these can be resolved by detailed molecular genetic investigations.

Conclusion

The findings confirm that trisomic pregnancies may demonstrate morphological villous features similar to hydatidiform mole, and that loss of p57^KIP2 expression occurs due to an absence of maternally transcribed genes on chromosome 11 and can therefore be independent of androgenetic complete hydatidiform mole.

Complications and Their Resolution in Recipients of Deceased and Living Donor Liver Transplants: Findings From the A2ALL Cohort Study

The purpose of this study was to explore long-term complications in recipients of deceased donor liver transplant (DDLT) and living donor liver transplant (LDLT) in the Adult-to-Adult Living Donor Liver Transplantation Cohort Study (A2ALL). We analyzed 471 DDLTs and 565 LDLTs from 1998 to 2010 that were followed up to 10 years for 36 categories of complications. Probabilities of complications and their resolutions were estimated using the Kaplan-Meier method, and predictors were tested in Cox proportional hazards models. Median follow-up for DDLT and LDLT was 4.19 and 4.80 years, respectively. DDLT recipients were more likely to have hepatocellular carcinoma and higher disease severity, including Model for End-Stage Liver Disease score. Complications occurring with higher probability in LDLT included biliary-related complications and hepatic artery thrombosis. In DDLT, ascites, intra-abdominal bleeding, cardiac complications and pulmonary edema were significantly more probable. Development of chronic kidney disease stage 4 or 5 was less likely in LDLT recipients (hazard ratio [HR] 0.41, p = 0.02). DDLT and LDLT had similar risk of grade 4 complications (HR 0.89, p = 0.60), adjusted for other risk factors. Once a complication occurred, the time to resolution did not differ between LDLT and DDLT. Future efforts should be directed toward reducing the occurrence of complications after liver transplantation.

Circulating Cell Free DNA in the Diagnosis of Trophoblastic Tumors

Gestational trophoblastic neoplasia (GTN) represents a group of diseases characterized by production of human chorionic gonadotropin (hCG). Since non-gestational tumors may occasionally secrete hCG, histopathological diagnosis is important for appropriate clinical management. However, a histopathological diagnosis is not always available. We therefore investigated the feasibility of extracting cell free DNA (cfDNA) from the plasma of women with GTN for use as a “liquid biopsy” in patients without histopathological diagnosis. cfDNA was prepared from the plasma of 20 women with a diagnosis of GTN and five with hCG-secreting tumors of unknown origin. Genotyping of cfDNA from the patient, genomic DNA from her and her partner and DNA from the tumor tissue identified circulating tumor DNA (ctDNA) (from 9% to 53% of total cfDNA) in 12 of 20 patients with GTN. In one case without a tissue diagnosis, ctDNA enabled a diagnosis of GTN originating in a non-molar conception and in another a diagnosis of non-gestational tumor, based on the high degree of allelic instability and loss of heterozygosity in the ctDNA. In summary ctDNA can be detected in the plasma of women with GTN and can facilitate the diagnosis of both gestational and non-gestational trophoblastic tumors in cases without histopathological diagnosis.

•

Circulating tumor DNA can be detected in the plasma of patients with gestational trophoblastic neoplasia.

•

Analysis of circulating tumor DNA may provide a diagnosis in patients with hCG-secreting tumors and no tissue biopsy.

•

ctDNA may provide a source of tumor DNA for further investigation of gestational trophoblastic neoplasia.

Gestational trophoblastic neoplasia describes a group of pregnancy related cancers. These cancers produce the pregnancy hormone human chorionic gonadotropin (hCG) which is useful in diagnosing and monitoring the disease. Some non-pregnancy related cancers may also make hCG causing difficulty with diagnosis in patients without a biopsy for pathological diagnosis.

In this study we detected DNA from the cancer in patients' blood. Analysis of this DNA enabled us to distinguish cancers that were pregnancy related from those that were not. In the future we may use this technology to help diagnose pregnancy related cancers in patients where a biopsy is unavailable.

Paternal Hemizygosity in 11p15 in Mole-like Conceptuses: Two Case Reports

Hydatidiform mole is an abnormal human pregnancy characterized by the fetus being absent or nonviable, and the chorionic villi being vesicular and with trophoblastic hyperplasia. Most often, the mole phenotype is seen in conceptuses with an excess of paternally inherited genome set(s) relative to maternally inherited genome set(s), suggesting that the phenotype is caused by an excess of genome with a paternal imprinting pattern. However, it is unknown if correct parental origin of every imprinted gene is crucial for normal early differentiation or if abnormal parental imprinting of only one, or some, gene(s) can cause the mole phenotype.Two conceptuses included in the Danish Mole Project stood out since they presented with vesicular chorionic villi and without signs of fetal differentiation, and had apparently biparental diploid genomes, and no mutations in NLRP7 or KHDC3L were detected in the mothers. These conceptuses were subjected to a centralized histopathological revision and their genetic complements were scrutinized using fluorescence in situ hybridization, and DNA-marker and array comparative genomic hybridization analyses. Both conceptuses showed dysmorphic chorionic villi with some similarities to hydatidiform moles; however, no definite florid trophoblast hyperplasia was observed. Both conceptuses showed paternal hemizygosity of 11pter-11p15.4, most likely in nonmosaic state.Our findings suggest that the product of one (or a few) maternally expressed gene(s) on the tip of chromosome 11 is necessary for normal early embryonic differentiation. However, since the present two cases did not exhibit all features of hydatidiform moles, it is likely that abnormal parental imprinting of genes in other regions contribute to the phenotype of a hydatidiform mole.

No evidence for mutations in NLRP7, NLRP2 or KHDC3L in women with unexplained recurrent pregnancy loss or infertility

STUDY QUESTION

Are mutations in NLRP2/7 (NACHT, LRR and PYD domains-containing protein 2/7) or KHDC3L (KH Domain Containing 3 Like) associated with recurrent pregnancy loss (RPL) or infertility?

SUMMARY ANSWER

We found no evidence for mutations in NLRP2/7 or KHDC3L in unexplained RPL or infertility.

WHAT IS KNOWN ALREADY

Mutations in NLRP7 and KHDC3L are known to cause biparental hydatidiform moles (BiHMs), a rare form of pregnancy loss. NLRP2, while not associated with the BiHM pathology, is known to cause recurrent Beckwith Weidemann Syndrome (BWS).

STUDY DESIGN, SIZE, AND DURATION

Ninety-four patients with well characterized, unexplained infertility were recruited over a 9-year period from three IVF clinics in Sweden. Blood samples from 24 patients with 3 or more consecutive miscarriages of unknown etiology were provided by the Recurrent Miscarriage Clinic at St Mary's Hospital, London, UK.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Patients were recruited into both cohorts following extensive clinical studies. Genomic DNA was isolated from peripheral blood and subject to Sanger sequencing of NLRP2, NLRP7 and KHDC3L. Sequence electropherograms were analyzed by Sequencher v5.0 software and variants compared with those observed in the 1000 Genomes, single nucleotide polymorphism database (dbSNP) and HapMap databases. Functional effects of non-synonymous variants were predicted using Polyphen-2 and sorting intolerant from tolerant (SIFT).

MAIN RESULTS AND THE ROLE OF CHANCE

No disease-causing mutations were identified in NLRP2, NLRP7 and KHDC3L in our cohorts of unexplained infertility and RPL.

LIMITATIONS, REASONS FOR CAUTION

Due to the limited patient size, it is difficult to conclude if the low frequency single nucleotide polymorphisms observed in the present study are causative of the phenotype. The design of the present study therefore is only capable of detecting highly penetrant mutations.

WIDER IMPLICATIONS OF THE FINDINGS

The present study supports the hypothesis that mutations in NLRP7 and KHDC3L are specific for the BiHM phenotype and do not play a role in other adverse reproductive outcomes. Furthermore, to date, mutations in NLRP2 have only been associated with the imprinting disorder BWS in offspring and there is no evidence for a role in molar pregnancies, RPL or unexplained infertility.

STUDY FUNDING/COMPETING INTERESTS

This study was funded by the following sources: Estonian Ministry of Education and Research (Grant SF0180044s09), Enterprise Estonia (Grant EU30020); Mentored Resident research project (Department of Obstetrics and Gynecology, Baylor College of Medicine); Imperial NIHR Biomedical Research Centre; Grant Number C06RR029965 from the National Center for Research Resources (NCCR; NIH). No competing interests declared.

Clinical utility of selective molecular genotyping for diagnosis of partial hydatidiform mole; a retrospective study from a regional trophoblastic disease unit

AIMS

Hydatidiform moles (HMs) are genetically abnormal conceptions, associated with increased risk of gestational trophoblastic neoplasia. Diagnosis is usually based on histopathological criteria but in a minority definitive histological diagnosis is not possible; in such cases molecular genotyping may be diagnostic. This study describes the clinical usefulness of such an approach.

METHODS

Cases in which central histology review demonstrated abnormal villous morphological features insufficient for definite diagnosis of partial HM (PHM) ('favour PHM' or 'PHM not excluded') underwent molecular genotyping of villous and maternal tissue, using short tandem repeats, to determine ploidy and parental origin of the placental tissue.

RESULTS

Of 251 cases with non-diagnostic morphological villous abnormalities, molecular investigation was not possible in 14 (6%; limited material or technical issues). Overall, 124 (49%) were triploid including 71/86 (85%) of those morphologically favouring PHM, and 53/165 (32%) of those favouring non-molar miscarriage. Of 85 cases of triploidy in whom sufficient material was available, 84 had an additional paternal contribution. Single cases of digynic triploidy, tetraploid PHM and two mosaic conceptions were also identified. Twenty-three non-molar diploid cases (21%) exhibited trisomy.

CONCLUSIONS

Molecular genotyping allows definitive diagnosis of PHM for cases in which specialist histopathology review remains equivocal. While this approach provides definite diagnosis it is considerably more expensive than a pragmatic management approach of human chorionic gonadotrophin surveillance in all such cases.

Histopathological and immunohistochemical features of early hydatidiform mole in relation to subsequent development of persistent gestational trophoblastic disease

OBJECTIVE

To examine histomorphological and immunohistochemical findings in hydatidiform moles to determine whether any features can reliably predict clinical behavior.

STUDY DESIGN

Blinded semiquantitative review of histological and immunohistochemical findings in cases of partial hydatidiform mole (PHM) (N = 50) and complete hydatidiform mole (CHM) which either spontaneously resolved (N = 50) or required chemotherapy (N = 50). Immunostains assessed included MLH1, MSH2, nm23, TERT, p53, EGFR, and CerbB2 based on previous data.

RESULTS

There were marked morphological differences in various criteria between CHMs and PHMs, including the proportion of villi with abnormal trophoblast hyperplasia (29% vs. 6%, respectively). However, there were no significant differences in any morphological parameters between CHMs that spontaneously resolved and those that subsequently required chemotherapy. Similarly, there were no clinically useful differences regarding any immunostaining scores between CHM groups.

CONCLUSION

Neither morphological nor immunohistochemical features can reliably predict subsequent requirement of chemotherapy in CHMs.

Management and survival of patients with FIGO high-risk gestational trophoblastic neoplasia: the U.K. experience, 1995-2010

OBJECTIVE

To present survival rates of high-risk gestational trophoblastic neoplasia (GTN) (FIGO score > 7) patients treated between 1995 and 2010 in the U.K. Death due to GTN is largely confined to patients with high-risk disease. In the U.K. a national system ensures that all patients are treated at only 2 specialist centers: Charing Cross Hospital (CXH) in London and Weston Park Hospital (WPH) in Sheffield.

STUDY DESIGN

A total of 196 high-risk patients were identified using the CXH and WPH GTN databases, based on the risk score at the time of presentation.

RESULTS

In all, 140 CXH and 56 WPH high-risk patients were treated with EMA/CO (etoposide, methotrexate, actinomycin D alternating with cyclophosphamide and vincristine) and MEA (methotrexate, etoposide, actinomycin D), respectively. The FIGO score at presentation ranged from 6-23. Eight patients (7from WPH and 1 from CXH) who were treated prior to 2002 as high-risk based on their pre-2002 scoring scored a 6 using FIGO 2002. Two (1%) patients died within 4 weeks of starting treatment (early death), 12 (6%) relapsed, and 9 patients subsequently died due to drug resistance. The overall survival was 94%, with a median follow-up of 4.69 years.

CONCLUSION

In the context of a national trophoblastic disease service, patients with high-risk GTN have an excellent prognosis with EMA/CO or MEA.

First confirmation by genotyping of transplacental choriocarcinoma transmission

A mother developed multimetastatic gestational choriocarcinoma 13 months after delivery, and her infant died aged 11 months from the same tumor. The transplacental choriocarcinoma transmission was confirmed by genotyping. Henceforth, we recommend a 2-year maternal human chorionic gonadotropin follow-up after neonatal choriocarcinoma and extensive imaging if the human chorionic gonadotropin rises.

RGS6 suppresses Ras-induced cellular transformation by facilitating Tip60-mediated Dnmt1 degradation and promoting apoptosis

The RAS protooncogene has a central role in regulation of cell proliferation, and point mutations leading to oncogenic activation of Ras occur in a large number of human cancers. Silencing of tumor-suppressor genes by DNA methyltransferase 1 (Dnmt1) is essential for oncogenic cellular transformation by Ras, and Dnmt1 is overexpressed in numerous human cancers. Here we provide new evidence that the pleiotropic regulator of G protein signaling (RGS) family member RGS6 suppresses Ras-induced cellular transformation by facilitating Tip60-mediated degradation of Dmnt1 and promoting apoptosis. Employing mouse embryonic fibroblasts from wild-type and RGS6(-/-) mice, we found that oncogenic Ras induced upregulation of RGS6, which in turn blocked Ras-induced cellular transformation. RGS6 functions to suppress cellular transformation in response to oncogenic Ras by downregulating Dnmt1 protein expression leading to inhibition of Dnmt1-mediated anti-apoptotic activity. Further experiments showed that RGS6 functions as a scaffolding protein for both Dnmt1 and Tip60 and is required for Tip60-mediated acetylation of Dnmt1 and subsequent Dnmt1 ubiquitylation and degradation. The RGS domain of RGS6, known only for its GTPase-activating protein activity toward Gα subunits, was sufficient to mediate Tip60 association with RGS6. This work demonstrates a novel signaling action for RGS6 in negative regulation of oncogene-induced transformation and provides new insights into our understanding of the mechanisms underlying Ras-induced oncogenic transformation and regulation of Dnmt1 expression. Importantly, these findings identify RGS6 as an essential cellular defender against oncogenic stress and a potential therapeutic target for developing new cancer treatments.

Partial molar pregnancy after intracytoplasmic sperm injection occurring as a result of diploid sperm usage

PURPOSE

Partial molar pregnancies are rare conceptions characterized by having 69 rather than 46 chromosomes, the additional chromosome complement usually occurring as a result of fertilization of the ovum by two sperm. Although assisted conception with intracytoplasmic sperm injection (ICSI) should prevent the development of a partial molar pregnancy, occasional cases have been described after assisted conception using ICSI. The objective of this study was to investigate the cause of partial molar pregnancy in a couple who had undertaken assisted conception with ICSI.

METHODS

Fluorescent microsatellite genotyping of DNA from the couple and tissue from their partial molar pregnancy was performed in order to confirm diagnosis and investigate the origin of the additional chromosome set.

RESULTS

Genotyping confirmed that the partial molar tissue was triploid with an additional chromosome complement from the father. Genotyping of additional loci proximal to the centromere demonstrated that the two paternal sets of chromosomes originated in a single sperm with a double complement of paternal DNA resulting from non-reduction at the second meiotic division.

CONCLUSIONS

This study confirms that partial molar pregnancy may occur after assisted conception with ICSI and that this occurs as a result of fertilization with a diploid sperm.

EMA/CO for high-risk gestational trophoblastic neoplasia: good outcomes with induction low-dose etoposide-cisplatin and genetic analysis

PURPOSE

Patients with high-risk (International Federation of Gynecology and Obstetrics score ≥ 7) gestational trophoblastic neoplasia (GTN) frequently receive etoposide, methotrexate, and dactinomycin alternating weekly with cyclophosphamide and vincristine (EMA/CO). Between 1979 and 1995, overall survival (OS) with this regimen at our institute was 85.4% with a significant proportion of early deaths (< 4 weeks). Here, we determine whether survival rates have improved in a more recent patient cohort (1995 to 2010).

PATIENTS AND METHODS

Patients receiving EMA/CO were identified using the Charing Cross GTN database. Genetic analysis identified nongestational trophoblastic tumors (nGTTs). The use of induction low-dose etoposide 100 mg/m(2) and cisplatin 20 mg/m(2) (EP; days 1 and 2 every 7 days) since 1995 to reduce early deaths before commencing EMA/CO was noted.

RESULTS

Four hundred thirty-eight patients received EMA/CO between 1995 and 2010. Six patients had nGTTs, 140 had high-risk disease, and 250 had relapsed/resistant low-risk GTN. OS was 94.3% in high-risk patients (90.4% including nGTTs) and 99.6% in the low-risk group, with a median follow-up time of 4.2 years. All patients with nGTT and seven patients with high-risk GTNs died as a result of drug-resistant disease. EP induction chemotherapy was given to 23.1% of high-risk patients (33 of 140 patients) with a large disease burden, and the early death rate was only 0.7% (n = 1; 95% CI, 0.1% to 3.7%) compared with 7.2% (n = 11 of 151 patients; 95% CI, 4.1% to 12.6%) in the pre-1995 cohort.

CONCLUSION

OS after EMA/CO for high-risk GTN has increased by nearly 9%. This reflects a more accurate estimate of OS by excluding nGTTs (3.9%) in patients with atypical presentations using genetic diagnosis. Low-dose induction EP in selected individuals also allows near complete elimination of early deaths. The latter should be considered routinely in high-risk GTN.

Mutations in NLRP7 and KHDC3L confer a complete hydatidiform mole phenotype on digynic triploid conceptions

Digynic triploidy is classically associated with a severely growth restricted fetus and a small nonmolar placenta. However, in genotyping hydatidiform moles as part of clinical practice, we identified two digynic triploid conceptions presenting with histopathological features of classical complete hydatidiform mole (CHM). Both cases occurred in women with a history of previous molar pregnancies and no normal pregnancies. Pathological review and genotyping of other molar pregnancies in these cases showed them to be typical CHM with negative p57(KIP2) immunostaining of the cytotrophoblast cells and villous stroma and to be diploid but biparental, confirming a diagnosis of familial recurrent hydatidiform mole (FRHM). Mutation screening of NLRP7 had identified a homozygous duplication, leading to a truncated protein, in case 1 whereas mutation screening of KHDC3L (C6orf221) in case 2 showed both the proband and her sister to be compound heterozygotes for mutations in KHDC3L. The observation of a single digynic, triploid conception presenting as a CHM in women with FRHM, where other pregnancies are diploid and biparental, supports the hypothesis that the role of both NLRP7 and KHDC3L in pregnancy is in setting and/or maintaining the maternal imprint. Clinically, a diagnosis of FRHM should be considered in women with genetically unusual conceptions that are phenotypically CHM.

Distinct activities of the anaphase-promoting complex/cyclosome (APC/C) in mouse embryonic cells

The first differentiation event in mammalian development gives rise to the blastocyst, consisting of two cell lineages that have also segregated in how the cell cycle is structured. Pluripotent cells of the inner cell mass divide mitotically to retain a diploid DNA content, but the outer trophoblast cells can amplify their genomes more than 500-fold by undergoing multiple rounds of DNA replication, completely bypassing mitosis. Central to this striking divergence in cell cycle control is the E3 ubiquitin-ligase activity of the anaphase-promoting complex or cyclosome (APC/C). Extended suppression of APC/C activity during interphase of mouse pluripotent cells promotes rapid cell cycle progression by allowing stabilization of cyclins, whereas unopposed APC/C activity during S phase of mouse trophoblast cells triggers proteasomal-mediated degradation of geminin and giant cell formation. While differential APC/C activity might govern the atypical cell cycles observed in pre-implantation mouse embryos, geminin is a critical APC/C substrate that: (1) escapes degradation in pluripotent cells to maintain expression of Oct4, Sox2 and Nanog; and (2) mediates specification and endoreduplication when targeted for ectopic destruction in trophoblast. Thus, in contrast to trophoblast giant cells that lack geminin, geminin is preserved in both mouse pluripotent cells and non-endoreduplicating human cytotrophoblast cells.

The association between cytomegalovirus immune globulin and long-term recipient and graft survival following liver transplantation

The association between cytomegalovirus (CMV) immune globulin (CMVIG) and long-term clinical outcomes has not been well defined. We examined the association between CMVIG and long-term recipient and graft survival in liver transplant recipients. Data were from the Scientific Registry of Transplant Recipients and included recipients transplanted between January 1995 and October 2008; follow-up was through March 2009. All recipients≤80 years of age with primary, single-organ liver transplants, given CMVIG with (n=2350) or without antivirals (n=455), antivirals without CMVIG (n = 32,939), or no CMV prophylaxis (n=28,508) before discharge were included. Kaplan-Meier analysis was used to examine rates of acute rejection (AR), graft loss, and death, over 7 years post transplantation. The adjusted risk of AR, graft loss, and death associated with CMVIG with and without antivirals vs. no prophylaxis was estimated using the Cox proportional hazards regression. In the univariate analysis, CMVIG, with and without antivirals, was associated with increased AR rates, but decreased mortality; CMVIG with antivirals was also associated with decreased graft loss compared with no prophylaxis. From the multivariable model, CMVIG with antivirals was associated with increased risk for AR, but decreased risk for graft loss and death; after adjustment, the association between CMVIG alone and mortality was not significant. CMVIG with antivirals is associated with increased risk of AR but greater long-term patient and graft survival after liver transplantation.

Transient over-expression of estrogen receptor-α in breast cancer cells promotes cell survival and estrogen-independent growth

Estrogen receptor-α (ERα) positive breast cancer frequently responds to inhibitors of ERα activity, such as tamoxifen, and/or to aromatase inhibitors that block estrogen biosynthesis. However, many patients become resistant to these agents through mechanisms that remain unclear. Previous studies have shown that expression of ERα in ERα-negative breast cancer cell lines frequently inhibits their growth. In order to determine the consequence of ERα over-expression in ERα-positive breast cancer cells, we over-expressed ERα in the MCF-7 breast cancer cell line using adenovirus gene transduction. ERα over-expression led to ligand-independent expression of the estrogen-regulated genes pS2 and PR and growth in the absence of estrogen. Interestingly, prolonged culturing of these cells in estrogen-free conditions led to the outgrowth of cells capable of growth in cultures from ERα transduced, but not in control cultures. From these cultures a line, MLET5, was established which remained ERα-positive, but grew in an estrogen-independent manner. Moreover, MLET5 cells were inhibited by anti-estrogens showing that ERα remains important for their growth. Gene expression microarray analysis comparing MCF-7 cells with MLET5 highlighted apoptosis as a major functional grouping that is altered in MLET5 cells, such that cell survival would be favoured. This conclusion was further substantiated by the demonstration that MLET5 show resistance to etoposide-induced apoptosis. As the gene expression microarray analysis also shows that the apoptosis gene set differentially expressed in MLET5 is enriched for estrogen-regulated genes, our findings suggest that transient over-expression of ERα could lead to increased cell survival and the development of estrogen-independent growth, thereby contributing to resistance to endocrine therapies in breast cancer patients.

Zinc poisoning from excessive denture fixative use masquerading as myelopolyneuropathy and hypocupraemia

A 50-year-old man presented with a four-year history of unsteadiness, with recent falls and tingling in his fingers. Neurological examination found an ataxic gait, with a positive Romberg's sign. There was distal wasting and weakness in all four limbs and impaired co-ordination, with pseudoathetosis in the arms. Initial investigations showed a normochromic, normocytic anaemia, leucopenia, neutropenia and a low vitamin B12 (172 ng/L). Treatment with intramuscular cobalamin injections showed no clinical improvement. Further investigations showed an undetectable caeruloplasmin (<0.085 g/L), a very low serum copper (1.1 μmol/L) and a markedly raised serum zinc concentration (36.2 μmol/L). On detailed questioning it became apparent that he had ill-fitting dentures requiring excessive use of denture fixative with high zinc content. The patient was switched to a non-zinc containing denture fixative and commenced copper supplementation. Although within three months the bone marrow suppression had resolved, there was no clinical improvement in neurological presentation. Questioning a patient about their denture fixative usage and checking if zinc is an ingredient may be considered during an investigation for myelopolyneuropathy when vitamin B12 deficiency is not a cause.

Shifts in plant respiration and carbon use efficiency at a large-scale drought experiment in the eastern Amazon

*The effects of drought on the Amazon rainforest are potentially large but remain poorly understood. Here, carbon (C) cycling after 5 yr of a large-scale through-fall exclusion (TFE) experiment excluding about 50% of incident rainfall from an eastern Amazon rainforest was compared with a nearby control plot. *Principal C stocks and fluxes were intensively measured in 2005. Additional minor components were either quantified in later site measurements or derived from the available literature. *Total ecosystem respiration (R(eco)) and total plant C expenditure (PCE, the sum of net primary productivity (NPP) and autotrophic respiration (R(auto))), were elevated on the TFE plot relative to the control. The increase in PCE and R(eco) was mainly caused by a rise in R(auto) from foliage and roots. Heterotrophic respiration did not differ substantially between plots. NPP was 2.4 +/- 1.4 t C ha(-1) yr(-1) lower on the TFE than the control. Ecosystem carbon use efficiency, the proportion of PCE invested in NPP, was lower in the TFE plot (0.24 +/- 0.04) than in the control (0.32 +/- 0.04). *Drought caused by the TFE treatment appeared to drive fundamental shifts in ecosystem C cycling with potentially important consequences for long-term forest C storage.

A novel DFNB1 deletion allele supports the existence of a distant cis-regulatory region that controls GJB2 and GJB6 expression

Eleven affected members of a large German-American family segregating recessively inherited, congenital, non-syndromic sensorineural hearing loss (SNHL) were found to be homozygous for the common 35delG mutation of GJB2, the gene encoding the gap junction protein Connexin 26. Surprisingly, four additional family members with bilateral profound SNHL carried only a single 35delG mutation. Previously, we demonstrated reduced expression of both GJB2 and GJB6 mRNA from the allele carried in trans with that bearing the 35delG mutation in these four persons. Using array comparative genome hybridization (array CGH), we have now identified on this allele a deletion of 131.4 kb whose proximal breakpoint lies more than 100 kb upstream of the transcriptional start sites of GJB2 and GJB6. This deletion, del(chr13:19,837,344-19,968,698), segregates as a completely penetrant DFNB1 allele in this family. It is not present in 528 persons with SNHL and monoallelic mutation of GJB2 or GJB6, and we have not identified any other candidate pathogenic copy number variation by arrayCGH in a subset of 10 such persons. Characterization of distant GJB2/GJB6 cis-regulatory regions evidenced by this allele may be required to find the 'missing' DFNB1 mutations that are believed to exist.

Calcineurin-inhibitor-free immunosuppression based on the JAK inhibitor CP-690,550: a pilot study in de novo kidney allograft recipients

This randomized, pilot study compared the Janus kinase inhibitor CP-690,550 (15 mg BID [CP15] and 30 mg BID [CP30], n = 20 each) with tacrolimus (n = 21) in de novo kidney allograft recipients. Patients received an IL-2 receptor antagonist, concomitant mycophenolate mofetil (MMF) and corticosteroids. CP-690,550 doses were reduced after 6 months. Due to a high incidence of BK virus nephropathy (BKN) in CP30, MMF was discontinued in this group. The 6-month biopsy-proven acute rejection rates were 1 of 20, 4 of 20 and 1 of 21 for CP15, CP30 and tacrolimus groups, respectively. BKN developed in 4 of 20 patients in CP30 group. The 6-month rates of cytomegalovirus disease were 2 of 20, 4 of 20 and none of 21 for CP15, CP30 and tacrolimus groups, respectively. Estimated glomerular filtration rate was >70 mL/min at 6 and 12 months (all groups). NK cells were reduced by </=77% in CP-690,550-treated patients. In the CP-690,550 arms, there were modest lipid elevations and a trend toward more frequent anemia and neutropenia during the first 6 months. These data suggest that coadministration of CP-690,550 30 mg BID with MMF is associated with overimmunosuppression. At 15 mg BID, the efficacy/safety profile was comparable to the tacrolimus control group, excepting a higher rate of viral infection. Further dose-ranging evaluation of CP-690,550 is warranted.

Calcineurin-inhibitor-free immunosuppression based on the JAK inhibitor CP-690,550: a pilot study in de novo kidney allograft recipients

This randomized, pilot study compared the Janus kinase inhibitor CP-690,550 (15 mg BID [CP15] and 30 mg BID [CP30], n = 20 each) with tacrolimus (n = 21) in de novo kidney allograft recipients. Patients received an IL-2 receptor antagonist, concomitant mycophenolate mofetil (MMF) and corticosteroids. CP-690,550 doses were reduced after 6 months. Due to a high incidence of BK virus nephropathy (BKN) in CP30, MMF was discontinued in this group. The 6-month biopsy-proven acute rejection rates were 1 of 20, 4 of 20 and 1 of 21 for CP15, CP30 and tacrolimus groups, respectively. BKN developed in 4 of 20 patients in CP30 group. The 6-month rates of cytomegalovirus disease were 2 of 20, 4 of 20 and none of 21 for CP15, CP30 and tacrolimus groups, respectively. Estimated glomerular filtration rate was >70 mL/min at 6 and 12 months (all groups). NK cells were reduced by </=77% in CP-690,550-treated patients. In the CP-690,550 arms, there were modest lipid elevations and a trend toward more frequent anemia and neutropenia during the first 6 months. These data suggest that coadministration of CP-690,550 30 mg BID with MMF is associated with overimmunosuppression. At 15 mg BID, the efficacy/safety profile was comparable to the tacrolimus control group, excepting a higher rate of viral infection. Further dose-ranging evaluation of CP-690,550 is warranted.

Prognostic markers and long-term outcome of placental-site trophoblastic tumours: a retrospective observational study

BACKGROUND

Placental-site trophoblastic tumours are a rare form of gestational trophoblastic disease and consequently information about optimum management or prognostic factors is restricted. We aimed to assess the long-term outcome of stage-adapted management by surgery, chemotherapy, or both for patients with the disorder.

METHODS

35 550 women were registered with gestational trophoblastic disease in the UK (1976-2006), of whom 62 were diagnosed with placental-site trophoblastic tumours and included, retrospectively, in the study. Patients were treated by surgery, chemotherapy, or both. We estimated the probabilities of overall survival and survival without recurrence of disease 5 and 10 years after the date of first treatment, and calculated the association of these endpoints with prognostic factors, including time since antecedent pregnancy, serum concentration of beta-human chorionic gonadotropin, and stage of disease, with both univariate and multivariate analyses.

FINDINGS

Probabilities of overall and recurrence-free survival 10 years after first treatment were 70% (95% CI 54-82) and 73% (54-85), respectively. Patients with stage I disease had a 10-year probability of overall survival of 90% (77-100) and did not benefit from postoperative chemotherapy. By contrast, patients with stage II, III, and IV disease required combined treatment with surgery and chemotherapy; probability of overall survival at 10 years was 52% (3-100) for patients with stage II disease and 49% (26-72) for stage III or IV disease. Outcome for patients who had recurrent or refractory disease was poor: only four (22%) patients achieved long-term survival beyond 60 months. Multivariate analysis showed that the only significant independent predictor of overall and recurrence-free survival was time since antecedent pregnancy. A cutoff point of 48 months since antecedent pregnancy could differentiate between patients' probability of survival (<48 months) or death (>/=48 months) with 93% specificity and 100% sensitivity, and with a positive predictive value of 100% and a negative predictive value of 98%.

INTERPRETATION

Stage-adapted management with surgery for stage I disease, and combined surgery and chemotherapy for stage II, III, and IV disease could improve the effectiveness of treatment for placental-site trophoblastic tumours. Use of 48 months since antecedent pregnancy as a prognostic indicator of survival could help select patients for risk-adapted treatment.

FUNDING

National Commissioning Group.

Inheritance of beta-mannosidosis in goats

Plasma levels of beta-mannosidase activity were measured in the phenotypically normal members of a family of goats in which 12 cases of beta-mannosidosis have been reported. Normal or carrier genotypes were assigned on the basis of these results, and mating tables drawn up. Similar data were collected on a number of other small families unrelated to the one with beta-mannosidosis. The results indicate that the plasma beta-mannosidase level is a reasonably good indicator of carrier status and confirm that the disease beta-mannosidosis is inherited in a recessive manner and is not X-linked.

Isoelectric focusing of horse serum esterase isozymes and detection of new phenotypes

A new method for separating the isozymes of horse serum esterase is described. The improved resolution has enabled us to detect several previously undescribed phenotypes. This method has also been used to detect two different apparently 'silent' alleles.

An investigation of seven enzymes as possible genetic markers in horse leucocytes

In this paper we describe seven enzymes, NP, GOTM, PGM2, alpha FUC, PEP A, ADA and MPI which are found in the white cells of horses, including 39 British crossbred ponies and 16 crossbred horses, 30 Mongolian ponies and 10 Icelandic ponies. Two of these enzymes--alpha FUC and MPI--were polymorphic in all the populations of horses studied and could prove useful as additional markers in the paternity testing of horses. PEP A and GOTM were also polymorphic in two of the populations studied and could be used as further markers in these populations.