Frequent DYSF rare variants/mutations in 152 Han Chinese samples with ovarian endometriosis.

PURPOSE: Endometriosis is a common chronic gynecological disease greatly affecting women health. Prior studies have implicated that dysferlin (DYSF) aberration might be involved in the pathogenesis of ovarian endometriosis. In the present study, we explore the potential presence of DYSF mutations in a total of 152 Han Chinese samples with ovarian endometriosis. METHODS: We analyze the potential presence of DYSF mutations by direct DNA sequencing. RESULTS: A total of seven rare variants/mutations in the DYSF gene in 10 out of 152 samples (6.6%) were identified, including 5 rare variants and 2 novel mutations. For the 5 rare variants, p.R334W and p.G941S existed in 2 samples, p.R865W, p.R1173H and p.G1531S existed in single sample, respectively; for the two novel mutations, p.W352* and p.I1642F, they were identified in three patients. These rare variants/mutations were absent or existed at extremely low frequency either in our 1006 local control women without endometriosis, or in the China Metabolic Analytics Project (ChinaMAP) and Genome Aggregation Database (gnomAD) databases. Evolutionary conservation analysis results suggested that all of these rare variants/mutations were evolutionarily conserved among 11 vertebrate species from Human to Fox. Furthermore, in silico analysis results suggested these rare variants/mutations were disease-causing. Nevertheless, we find no significant association between DYSF rare variants/mutations and the clinical features in our patients. To our knowledge, this is the first report revealing frequent DYSF mutations in ovarian endometriosis. CONCLUSION: We identified a high frequency of DYSF rare variants/mutations in ovarian endometriosis for the first time. This study suggests a new correlation between DYSF rare variants/mutations and ovarian endometriosis, implicating DYSF rare variants/mutations might be positively involved in the pathogenesis of ovarian endometriosis.

ITRAQ-based proteomics analysis of tanshinone IIA on human ectopic endometrial stromal cells of adenomyosis.

PURPOSE: Adenomyosis is a diffuse or localized disease. Our previous study has indicated that tanshinone IIA (TSIIA) inhibits the proliferation, migration, and induces apoptosis of ectopic endometrial stromal cells (EESCs) of adenomyosis. However, the complex molecular mechanism of TSIIA in adenomyosis remains unclear. The objective of this study was to explore the complex molecular mechanism of TSIIA on EESCs. METHODS: In our present study, we used the proteomics approach iTRAQ (isobaric tags for relative and absolute quantitation) combined with LC-MS/MS (liquid chromatography-mass spectrometry) to investigate changes in the protein profile of EESCs treated with TSIIA. Differential proteins were analyzed by employing bioinformatics tools and the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. In TSIIA treated EESCs, the protein expression levels of TNFRSF10D, PLEKHM1, FECH, and TPM1A were detected by western blotting. RESULTS: Quantitative results revealed 267 significantly differential proteins in TSIIA pretreated EESCs. Gene Ontology (GO) analysis presented an overview of dysregulated proteins in the biological process (BP), cell component (CC), and molecular function (MF) categories. Interestingly, we observed that differential proteins in the extracellular matrix (ECM)-receptor interaction pathway and estrogen signaling pathway were all involved in the focal adhesion pathway, which plays essential roles in the TSIIA-mediated inhibition of EESC proliferation and migration. Furthermore, some significantly differential proteins, which may be potential targets for the treatment of adenomyosis in the future, were validated by western blotting. CONCLUSIONS: Our study provides a useful method to detect the detailed mechanism underlying the efficacy of TSIIA on EESCs.

[MGRN1 affects the mitophagy of spermatogonial stem cells in mice].

Objective: To study the effect of mahogunin ring finger-1 (MGRN1) on the mitophagy of the spermatogonial stem cells (SSC) in mice. METHODS: SSCs cultured in vitro were divided into three groups: empty vector control, MGRN1 (MGRN1 in SSCs knocked down by RNAi), and MGRN1 + FCCP (inducing mitophagy with carbonyl cyanide p-trifluoromethoxyphenylhydrazone ï¼»FCCPï¼½ in the SSCs with down-regulated MGRN1). The expressions of mitochondrial function-related proteins (Cytochromo c and COX IV) and mitophagy-related proteins (LC3, P62, FUNDC1 and CK2) and the phosphorylation of FUNDC1 were detected by Western blot. Mitochondria and mitochondrial autophagosomes in the SSCs were observed under the electron microscope. RESULTS: Compared with the empty vector control group, the MGRN1 and MGRN1 + FCCP groups showed significantly down-regulated expressions of Cytochromo c, Cox IV, LC3 and P62, increased phosphorylation level of FUNDC1, and up-regulated expression of CK2 in the SSCs (P < 0.05). No statistically significant differences were found in the expressions of Cytochromo c, Cox IV, LC3, P62 and CK2 or in the phosphorylation level of FUNDC1 between the MGRN1 and MGRN1 + FCCP groups (P > 0.05). Electron microscopy manifested increased mitochondrial damage and reduced mitochondrial autophagosomes in the SSCs in the MGRN1 and MGRN1 + FCCP groups compared with those in the control group. CONCLUSIONS: MGRN1 affects mitophagy in the SSCs of mice, which may be associated with the effect of CK2 on the phosphorylation of FUNDC1, and its molecular mechanism needs to be further studied.

[Influence of MGRN1 on the autophagy of Sertoli cells in mice].

OBJECTIVE: To study the effect of mahogunin ring finger-1 (MGRN1) on the autophagy of Sertoli cells in mice. METHODS: Using RNA interference, we down-regulated the expression of MGRN1 in the mouse TM4 Sertoli cells cultured in vitro, determined the expressions of the autophagy-related proteins LC3-II/I, ATG-5 and ATG-7 by Western blot, and detected the autophagosomes in the TM4 cells by immunofluorescence and electron microscopy. RESULTS: Western blot showed increased expressions of LC3-II/I, ATG-5 and ATG-7 in the mouse TM4 Sertoli cells after knockdown of MGRN1. Fluorescence microscopy revealed significantly more autophagosomes in the TM4 cells than in the control group (P < 0.05). CONCLUSIONS: MGRN1 affects the autophagy of mouse Sertoli cells, and its specific molecular mechanism needs to be further studied.

Suppression of PRDX4 inhibits cell proliferation and invasion of ectopic endometrial stromal cells in endometriosis.

Oxidative stress (OS) has been proposed to play a role in the development of EMs. Peroxiredoxins are a family of antioxidant proteins that exhibit peroxidase activity in a thioredoxin-dependent manner, protecting cells against OS. The Western blotting results showed that the relative expression of PRDX4 was significantly increased in ectopic endometria compared with the normal endometria of EMs-free (p < .05). The H2O2 concentration was also significantly higher in the ectopic endometrium. PRDX4 siRNA was transfected into primary ectopic endometrial stromal cells (EESCs). The viability of the transfected EESCs was measured by CCK-8 assay, and the results showed significantly decreased cell viability. Furthermore, the apoptosis rate and ROS generation in flow cytometry assays were significantly increased after the knockdown of PRDX4 expression (p < .05). Scratch assays and transwell assays revealed that decreased expression of PRDX4 mediated by siRNA inhibited EESC migration and invasion. In conclusion, these findings indicate the potential role of PRDX4 in the development of EMs and PRDX4 as a possible therapeutic target for EMs treatment.

Novel MYH8 mutations in 152 Han Chinese samples with ovarian endometriosis.

Endometriosis is a common gynecological disease affecting up to 10% of women at reproductive age. Prior combined studies implied that MYH8 mutations might exist in endometriosis. Here, 152 Han Chinese samples with ovarian endometriosis were analyzed for the presence of MYH8 mutations. Two heterozygous missense mutations in the MYH8 gene, c.1441A > C (p.I481L) and c.4057G > A (p.E1353K), were identified in our samples. These mutations were neither found in public databases nor detected in our 485 Han Chinese control women without endometriosis. The p.I481L-mutated sample belonged to 34-year-old, who had slightly elevated serum CA 125 (42.09 U/mL); while the sample with p.E1353K mutation belonged to 25 years old, who had a markedly increased serum CA125 (89.86 U/mL). The evolutionary conservation analysis results suggested that these MYH8 mutations caused highly conserved amino acid substitutions among vertebrate species. Both the mutations were predicted to be 'disease causing' by MutationTaster and SIFT programs. In addition, no association was observed between MYH8 mutations and the available clinical data. In summary, the present study identified two novel potential pathogenic mutations in the MYH8 gene in samples with ovarian endometriosis for the first time, implying that MYH8 mutations might play a positive role in the pathogenesis of endometriosis.

The Expression of MBD6 Is Associated with Tumor Size in Uterine Leiomyomas.

Background: Uterine leiomyoma (UL) is the most common benign smooth muscle tumor of the uterus in reproductive women. Prior studies indicated that methyl-CpG-binding domain proteins (MBDs) may be involved in the pathogenesis of UL. Materials and Methods: In this study, UL tissues and paired adjacent myometrium were collected from a total of 51 patients. The expression of MBD mRNAs and their cognate proteins were analyzed via quantitative polymerase chain reaction assays and western blotting, respectively. The relationships between the MBD expression levels and the patients' clinicopathologic variables were assessed using Student's t test, nonparametric tests, or Pearson χ2 methods. Results: Our results show that both the mRNA and protein levels of MBD2 were significantly decreased in ULs compared to the adjacent myometrium. In addition, MBD6 protein expression was also decreased significantly in UL samples when compared to the adjacent myometrium. There was, however, no significant difference on the mRNA expression of MBD6 between these two groups. Neither the mRNA nor the protein levels of the other MBD members (MBD1, MBD3, MBD4, MBD5, and MeCP2) showed any significant differences between ULs and the adjacent myometria. The decreased expression of the MBD6 protein was correlated with the tumor size of ULs. Conclusions: These results suggest that the dysregulated expression of MBD2 and MBD6 in ULs may play a role in their development; however, a larger sample size together with cellular functional assays should be carried out to further elucidate the precise role of MBD6 in ULs.

The mitochondrial DNA 4977-bp deletion and copy number alteration in Han Chinese samples with uterine fibroids.

Uterine fibroids (UFs) are the most common benign neoplasms, but their pathogenesis is not completely understood. Thus far, alterations in the mitochondrial DNA (mtDNA) content and the mtDNA 4977-bp deletion level in UFs, as well as the corresponding nontumorous tissue, have remained elusive. To test whether large mtDNA deletions and mtDNA content are involved in the pathogenesis of UFs, a total of 309 UF tissues and 28 paired adjacent myometrium from 270 UF patients were enrolled for the analysis of large mtDNA deletions and mtDNA content through the use of nested PCR and qPCR techniques, respectively. In our samples, a 4977-bp deletion was identified: 36 out of 309 UF tissues (11.56%) and 15 out of 28 (53.57%) paired adjacent myometrium were detected to harbor the 4977-bp deletion. In addition, a novel 4838-bp mtDNA deletion was identified in three UF tissues, and other different sizes of deleted fragments (4910, 4926, 5135-bp) were also found in UFs for the first time. Furthermore, older age was significantly associated with an mtDNA large deletion in the paired adjacent myometrium. We also found that increased mtDNA content and higher expression of ND1 occurred in solitary fibroids compared to adjacent myometrium. In conclusion, we identified a lower frequency of mtDNA large deletions and some novel large deletion in UFs for the first time. Furthermore, there was a general increase of mtDNA copy number during solitary UF development. Although the definite mechanism by which mtDNA was altered is supposed to be further confirmed, it will be helpful for further studies on the pathological mechanism of UFs.

Mutation analysis of ZP1, ZP2, ZP3 and ZP4 genes in 152 Han Chinese samples with ovarian endometriosis.

Endometriosis is characterized by the ectopic implant of endometrial tissue outside the uterine cavity and found in ˜35-50% of subfertile women. Previous studies have found that endometriosis had frequent defects in zona pellucida (ZP), and mutations in ZP genes could lead to ZP defects, raising the possibility that mutations in ZP genes might exist in endometriosis. We analyzed a total of 152 Han Chinese samples with ovarian endometriosis for the presence of mutations in the ZP1, ZP2, ZP3 and ZP4 genes. Two novel nonsynonymous ZP4 mutations were identified in three out of 152 (2.0%) samples: a p.M1?/(c.3 G > C) mutation in a 27- and 35-year-old sample, respectively, and a p.A433 V (c.1298C > T) mutation in a 31-year-old patient. No mutations were detected in ZP1, ZP2 or ZP3 genes; furthermore, no mutations in ZP genes were identified in 85 female control samples without endometriosis. The p.M1?/(c.3 G > C) mutation could lead to the usage of a downstream translation initiation site, while the evolutionary conservation and protein structural modeling analyses suggested that the p.A433 V mutation might be functionally important. However, there were strikingly different fertility outcomes among the three samples with ZP4 mutations: the p.A433V-mutated sample had no problem in fertility; while the p.M1?-mutated samples presented with paradoxical effects on fertility: the 35-year-old patient had a child while the 27-year-old patient was infertile, who underwent two spontaneous abortions and an implantation failure after IVF treatment. These results suggested that the potential role of ZP4 mutations on human fertility might be more complex than we thought, and other genetic and environment factors might play a role. In conclusion, we identified two novel mutations in the ZP4 gene in 2.0% of Han Chinese patients with ovarian endometriosis for the first time, our results suggested that mutations in ZP4, but not ZP1, ZP2 and ZP3, might play active roles in the pathogenesis of ovarian endometriosis, despite the mutation-carriers present with complex fertility outcomes.

Analysis of CARD10 and CARD11 somatic mutations in patients with ovarian endometriosis.

Endometriosis is a complex and heterogeneous pre-malignant inflammatory disease harboring multiple gene mutations. Previous studies have suggested that caspase recruitment domain family member (CARD)10 and CARD11 mutations may exist in endometriosis. In the present study, a collection of endometriotic lesions and paired peripheral blood from 101 patients with ovarian endometriosis were obtained, and the entire coding sequences of the CARD10 and CARD11 genes were sequenced. Evolutionary conservation analysis and online prediction programs were applied to analyze the disease-causing potential of the identified mutations. A total of 4 novel somatic mutations were identified in 4 out of the 101 (4.0%) samples: 2 in-frame deletions in CARD10 (c.785_790delAGGAGA, p.K272_E273delKE; c.785_802delAGGAGAAGGAGAAGGAGA, p.K272_V277delKEPDNV) and 2 heterozygous missense mutations in CARD11 (c.49G>T, p.D17Y; c.160G>C, p.E54Q). The sample with CARD10 p.K272_E273delKE deletion was obtained from a 47-year-old patient who was also diagnosed with uterine leiomyoma, while the CARD10 p.K272_V277delKEPDNV-mutated sample was from a 43-year-old patient exhibiting a decreased blood eosinophil granulocyte ratio (0.3%) and an elevated serum creatine kinase level (314 U/l). The patient with the CARD11 p.D17Y mutation was 38 years old and exhibited an increased level of cancer antigen 125 (45.4 U/ml), while the patient with the CARD11 p.E54Q mutation was 46 years old and exhibited no other gynecological conditions. Evolutionary conservation analysis and online prediction programs suggested that these mutations may be disease-causing. In summary, 4 novel somatic mutations in the CARD10 and CARD11 genes were identified from amongst 101 cases of ovarian endometriosis for the first time, these mutations may serve active roles in the development of ovarian endometriosis.

The presence of KRAS, PPP2R1A and ARID1A mutations in 101 Chinese samples with ovarian endometriosis.

Endometriosis is a potential premalignant disorder. The underlying molecular aberrations, however, are not fully understood. A recent exome sequencing study found that 25% (10/39) of deep infiltrating endometriosis harbored cancer driver gene mutations. However, it is unclear whether these mutations also exist in ovarian endometriosis. Here, a total of 101 ovarian endometriosis samples were analyzed for the presence of these gene mutations, including KRAS, PPP2R1A, PIK3CA and ARID1A. In addition, 6 other cancer-associated genes (BRAF, NRAS, HRAS, ERK1, ERK2 and PTEN) were also analyzed. In total, four somatic mutations were identified in three out of 101 ovarian endometriotic lesions (4%, 4/101), including a KRAS p.G12V, a PPP2R1A p.S256F and two ARID1A nonsense mutations (p.Q403* and p.G1926*); while no mutations were identified in the remaining 7 genes (BRAF, NRAS, HRAS, ERK1, ERK2, PTEN and PIK3CA). Note that the KRAS G12V and ARID1A Q403* mutations co-occurred in a 36-year-old sample who had a high serum CA125 (308.4 U/mL) and a late menarche age (18-year-old). Additionally, no mutations in any of the 10 genes were identified in either the healthy eutopic endometrial tissues from 85 control individuals without endometriosis, or in 62 healthy ovarian tissues from ovarian cysts samples (without endometriosis). Our study revealed, for the first time, the presence of classical cancer driver gene mutations in ovarian endometriosis. Furthermore, the co-occurrence of KRAS and ARID1A mutations was identified in a single individual for the first time. The observations of cancer driver gene mutations in our ovarian endometriosis samples, together with several prior observations, further support the notion that endometriosis is a premalignant disorder.

Mutational analysis of the RAS/RAF/MEK/ERK signaling pathway in 260 Han Chinese patients with cervical carcinoma.

Prevalent mutations in the mitogen-activated protein kinase 1 (MAPK1)/extracellular signal-regulated kinase 2 (ERK2) pathway have been identified in cervical squamous cell carcinoma in a large-scale genome sequencing effort. Furthermore, mutations in the rat sarcoma viral oncogene homolog (RAS)/Raf/Mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling pathway have also been revealed to have important roles in the pathogenesis of human cancer. However, whether the potential hotspot mutations in ERK2 and other components of the RAS/RAF/MEK/ERK signaling pathway also exist in Chinese patients with cervical carcinoma remains to be elucidated. In the present study, a total of 260 patients with cervical carcinoma of distinct subtypes were analyzed for the presence of potential hotspot mutations in the RAS/RAF/MEK/ERK signaling pathway. No ERK2 mutations were detected in these samples; however, Kirsten RAS (KRAS) p.G12D (c.35G>A) mutation was identified in 2/26 (7.7%) cervical adenocarcinoma cases, including 1/20 cervical mucinous adenocarcinoma and 1/6 cervical endometrioid carcinoma cases. In addition, no mutations in the ERK1, neuroblastoma RAS, Harvey RAS or B-Raf proto-oncogene serine/threonine kinase genes were detected in the present study. These results indicated that ethnic differences may be a primary reason for the discrepancy in ERK2 mutation frequencies between the current study and previous studies. Furthermore, mutation in the KRAS gene, but not other genes in the RAS/RAF/MEK/ERK signaling pathway, may have an active role in the pathogenesis of cervical carcinoma.

Prevalence and clinical significance of mediator complex subunit 12 mutations in 362 Han Chinese samples with uterine leiomyoma.

Uterine leiomyomas (ULs) are the most common gynecological benign tumors originating from the myometrium. Prevalent mutations in the mediator complex subunit 12 (MED12) gene have been identified in ULs, and functional evidence has revealed that these mutations may promote the development of ULs. However, whether MED12 mutations are associated with certain clinical characteristics in ULs remains largely unknown. In the present study, the potential mutations of MED12 and its paralogous gene, mediator complex subunit 12-like (MED12L), were screened in 362 UL tumors from Han Chinese patients. A total of 158 out of 362 UL tumors (43.6%) were identified as harboring MED12 somatic mutations, and the majority of these mutations were restricted to the 44th residue. MED12 mutations were also observed in 2 out of 145 (1.4%) adjacent control myometrium. Furthermore, the mutation spectrum of MED12 in the concurrent leiomyomas was noticeably different. Correlation analysis of MED12 mutations with the available clinical features indicated that patients with mutated MED12 tended to have smaller cervical diameters. By contrast, no MED12L mutation was identified in the present samples. In summary, the present study demonstrated the presence of prevalent MED12 somatic mutations in UL samples, and the MED12 mutation was associated with smaller cervical diameters. The low mutation frequency of MED12 in adjacent control myometrium indicated that MED12 mutation may be an early event in the pathogenesis of ULs. Furthermore, MED12 mutation status in concurrent tumors from multiple leiomyomas supported several prior observations that the majority of these tumors arose independently.

Downregulation of DNA methyltransferase 3 alpha promotes cell proliferation and invasion of ectopic endometrial stromal cells in adenomyosis.

Adenomyosis is a common benign gynecological condition in female reproductive tract and the detailed molecular etiology remains largely elusive. Previous studies implicated that deregulated expression of DNA (cytosine-5)-methyltransferase 3A (DNMT3A), a de novo DNA methyltransferase, might be involved in the pathogenesis of adenomyosis. Meanwhile, ectopic endometrial stromal cells (EESCs) were suggested to play crucial roles in adenomyosis. Herein, we evaluated the expression of DNMT3A protein in 36 ectopic endometriums with adenomyosis and 37 eutopic endometriums in controls with Western blotting (WB) or immunohistochemistry (IHC), we found that the expression of DNMT3A was significantly decreased in the ectopic endometriums and EESCs in adenomyosis relative to that of eutopic endometriums and EESCs in control samples, respectively. In addition, our functional assays revealed that overexpression of DNMT3A suppressed cell proliferation and invasion, while knockdown of DNMT3A enhanced cell proliferation and invasion in EESCs. Taken together, our results suggested that DNMT3A expression was decreased in ectopic endometriums and EESCs in adenomyosis, and we provided the first evidence that decreased DNMT3A expression in EESCs facilitated the development of adenomyosis via enhanced cell growth and invasion.

Medical swab touch spray-mass spectrometry for newborn screening of nicotine and cotinine in meconium.

Newborn screening is one of public health concerns designed to screen infants shortly after birth. Prenatal exposure to tobacco smoke such as nicotine has been reported to affect babies. Levels of nicotine and cotinine in meconium were widely used to evaluate the tobacco exposure of foetuses during pregnancy in a polluted environment. In this study, medical swabs were applied by using touch spray-mass spectrometry (TS-MS) to collect meconium from newborn infants for detection of nicotine and cotinine. Parameters such as choice of spray solvents, solvent volume and collision energy for screening of nicotine and cotinine were optimized. The limits of detection, reproducibility and matrix effect for analysis of meconium were also investigated. In this study, the levels of nicotine and cotinine in 54 puerpera volunteers were screened by TS-MS and were validated by using traditional liquid chromatography-mass spectrometry. These results showed that medical swab TS-MS would be useful for newborn screening of nicotine and cotinine in meconium with high reproducibility, speed, sensitivity and specificity. The use of disposable medical swabs involves no sample preparation and no chromatographic separation, significantly reducing the cost and time required for screening a large number of clinical sample. Copyright © 2016 John Wiley & Sons, Ltd.

A novel somatic MAPK1 mutation in primary ovarian mixed germ cell tumors.

A recent exome-sequencing study revealed prevalent mitogen-activated protein kinase 1 (MAPK1) p.E322K mutation in cervical carcinoma. It remains largely unknown whether ovarian carcinomas also harbor MAPK1 mutations. As paralogous gene mutations co­occur frequently in human malignancies, we analyzed here a total of 263 ovarian carcinomas for the presence of MAPK1 and paralogous MAPK3 mutations by DNA sequencing. A previously unreported MAPK1 p.D321N somatic mutation was identified in 2 out of 18 (11.1%) ovarian mixed germ cell tumors, while no other MAPK1 or MAPK3 mutation was detected in our samples. Of note, OCC­115, the MAPK1­mutated sample with bilateral cancerous ovaries affected, harbored MAPK1 mutation in the right ovary while retained the left ovary intact, implicating that the genetic alterations underlying ovarian mixed germ cell tumor may be different, even in patients with similar genetic backgrounds and tumor microenvironments. The results of evolutionary conservation and protein structure modeling analysis implicated that MAPK1 p.D321N mutation may be pathogenic. Additionally, mutations in protein phosphatase 2 regulatory subunit α (PPP2R1A), ring finger protein 43 (RNF43), DNA directed polymerase ε (POLE1), ribonuclease type III (DICER1), CCCTC­binding factor (CTCF), ribosomal protein L22 (RPL22), DNA methyltransferase 3α (DNMT3A), transformation/transcription domain­associated protein (TRRAP), isocitrate dehydrogenase (IDH)1 and IDH2 were not detected in ovarian mixed germ cell tumors, implicating these genetic alterations may be not associated with MAPK1 mutation in the development of this malignancy. The present study identified a previously unreported MAPK1 mutation in ovarian mixed germ cell tumors for the first time, and this mutation may be actively involved in the tumorigenesis of this disease.

Absence of DICER1, CTCF, RPL22, DNMT3A, TRRAP, IDH1 and IDH2 hotspot mutations in patients with various subtypes of ovarian carcinomas.

Cancer is caused by multiple genetic alterations within cells. Recently, large-scale sequencing has identified frequent ribonuclease type III (DICER1), CCCTC-binding factor (CTCF), ribosomal protein L22 (RPL22), DNA (cytosine-5-)-methyltransferase 3α (DNMT3A), transformation/transcription domain-associated protein (TRRAP), isocitrate dehydrogenase (IDH)1 and IDH2 hotspot mutations in diverse types of cancer. However, it remains largely unknown whether these mutations also exist in ovarian carcinomas. In the present study, a collection of 251 patients with distinct subtypes of ovarian carcinomas were recruited and sequenced for the presence of these hotspot mutations. However, no mutations in the seven genes were detected in the samples. These negative results, together with certain recent reports, indicate that the hotspot mutations in the CTCF, RPL22, DNMT3A, TRRAP, IDH1 and IDH2 genes may not be actively involved in the carcinogenesis of ovarian carcinoma. Of note, the DICER1 mutation frequency in Sertoli-Leydig cell tumor in the present study was significantly lower compared to prior observation, and therefore, it is speculated that this discrepancy may be mainly due to the small sample size analyzed in the study. In addition, among these samples, frequent polymerase (DNA directed) ε, catalytic subunit (POLE1) and ring finger protein 43 (RNF43) mutations were identified in endometrioid and mucinous ovarian carcinomas, respectively; thus DICER1, CTCF, RPL22, DNMT3A, TRRAP, IDH1 and IDH2 hotspot mutations may not play synergistic roles with POLE1 or RNF43 mutations in the carcinogenesis of endometrioid or mucinous ovarian carcinomas.

Frequent POLE1 p.S297F mutation in Chinese patients with ovarian endometrioid carcinoma.

The catalytic subunit of DNA polymerase epsilon (POLE1) functions primarily in nuclear DNA replication and repair. Recently, POLE1 mutations were detected frequently in colorectal and endometrial carcinomas while with lower frequency in several other types of cancer, and the p.P286R and p.V411L mutations were the potential mutation hotspots in human cancers. Nevertheless, the mutation frequency of POLE1 in ovarian cancer still remains largely unknown. Here, we screened a total of 251 Chinese samples with distinct subtypes of ovarian carcinoma for the presence of POLE1 hotspot mutations by direct sequencing. A heterozygous somatic POLE1 mutation, p.S297F (c.890C>T), but not p.P286R and p.V411L hotspot mutations observed in other cancer types, was identified in 3 out of 37 (8.1%) patients with ovarian endometrioid carcinoma; this mutation was evolutionarily highly conserved from Homo sapiens to Schizosaccharomyces. Of note, the POLE1 mutation coexisted with mutation in the ovarian cancer-associated PPP2R1A (protein phosphatase 2, regulatory subunit A, α) gene in a 46-year-old patient, who was also diagnosed with ectopic endometriosis in the benign ovary. In addition, a 45-year-old POLE1-mutated ovarian endometrioid carcinoma patient was also diagnosed with uterine leiomyoma while the remaining 52-year-old POLE1-mutated patient showed no additional distinctive clinical manifestation. In contrast to high frequency of POLE1 mutations in ovarian endometrioid carcinoma, no POLE1 mutations were identified in patients with other subtypes of ovarian carcinoma. Our results showed for the first time that the POLE1 p.S297F mutation, but not p.P286R and p.V411L hotspot mutations observed in other cancer types, was frequent in Chinese ovarian endometrioid carcinoma, but absent in other subtypes of ovarian carcinoma. These results implicated that POLE1 p.S297F mutation might be actively involved in the pathogenesis of ovarian endometrioid carcinoma, but might not be actively involved in other subtypes of ovarian carcinoma.

RNF43 mutations are recurrent in Chinese patients with mucinous ovarian carcinoma but absent in other subtypes of ovarian cancer.

Ring finger protein 43 (RNF43) is an E3 ubiquitin-protein ligase that accepts ubiquitin from an E2 ubiquitin-conjugating enzyme and directly transfers the ubiquitin to targeted substrate proteins. Recently, large-scale sequencing efforts have identified prevalent RNF43 mutations in pancreatic and ovarian mucinous carcinomas. In the present study, we sequenced the entire coding sequences of RNF43 in 251 Chinese patients with distinct subtypes of ovarian cancers for the presence of RNF43 mutations. A total of 2 novel heterozygous nonsynonymous RNF43 mutations were identified in 2 out of 15 (13.3%) patients with mucinous ovarian carcinoma, these mutations were evolutionarily highly conserved; while no mutation was detected in other samples. In addition, none of the RNF43-mutated samples harbored DICER1 (dicer 1, ribonuclease type III), PPP2R1A (protein phosphatase 2, regulatory subunit A, alpha), TRRAP (transformation/transcription domain-associated protein) and DNMT3A (DNA (cytosine-5-)-methyltransferase 3 alpha) hot-spot mutations. Recurrent RNF43 mutations existed in mucinous ovarian carcinomas implicated that these mutations might play crucial roles in the tumorigenesis of these patients, while the absence of DICER1, PPP2R1A, TRRAP and DNMT3A hot-spot mutations suggested that these genetic alterations might not play synergistic roles with RNF43 mutations in these individuals. Additionally, the absence of RNF43 mutations in other subtypes of ovarian carcinoma implicated that RNF43 mutations might not be actively involved in the pathogenesis of these disorders.

Infrequent mutations of the PPP2R1A and PPP2R1B genes in patients with ovarian cancer.

Protein phosphatase 2, regulatory subunit A, α (PPP2R1A) and ß (PPP2R1B) are paralogous subunits of the heterotrimeric protein phosphatase 2 (PP2A) holoenzyme that catalyzes the dephosphorylation of target substrate proteins. Subtype­specific PPP2R1A mutations have been frequently observed in ovarian and endometrial cancer. Mutations in the paralogous genes were frequently observed in human malignancies. Thus, the present study aimed to analyze the mutation frequencies of the paralogous PPP2R1A and PPP2R1B genes in patients with primary and secondary ovarian cancer. A total of 251 patients with primary (n=234) and secondary (n=17) ovarian cancer were analyzed for the presence of PPP2R1A and PPP2R1B mutations by direct sequencing. For PPP2R1A, a heterozygous, somatic mutation (c.771G>T, p.W257C) was identified in 1 out of 37 patients (2.7%) with primary ovarian endometrioid carcinoma. The mutant sample was that of a 46­year­old female, who was also diagnosed with ectopic endometriosis in the benign ovary. No PPP2R1A mutations were detected in the remaining 250 patients with ovarian cancer. For PPP2R1B, no mutations were detected in our samples. The results of this study suggested that PPP2R1A mutations are less common in Chinese patients with ovarian cancer when compared with European and American patients. Furthermore, our study also supported previous observations that PPP2R1B mutations were absent in ovarian cancer, suggesting that PPP2R1B mutations are not actively involved in the pathogenesis of ovarian cancer.