Polo-like kinase 1 (PLK1) O-GlcNAcylation is essential for dividing mammalian cells and inhibits uterine carcinoma.

The O-linked ß-N-acetylglucosamine (O-GlcNAc) transferase (OGT) mediates intracellular O-GlcNAcylation modification. O-GlcNAcylation occurs on Ser/Thr residues and is important for numerous physiological processes. OGT is essential for dividing mammalian cells and is involved in many human diseases; however, many of its fundamental substrates during cell division remain unknown. Here, we focus on the effect of OGT on polo-like kinase 1 (PLK1), a mitotic master kinase that governs DNA replication, mitotic entry, chromosome segregation, and mitotic exit. We show that PLK1 interacts with OGT and is O-GlcNAcylated. By utilizing stepped collisional energy/higher-energy collisional dissociation mass spectrometry, we found a peptide fragment of PLK1 that is modified by O-GlcNAc. Further mutation analysis of PLK1 shows that the T291A mutant decreases O-GlcNAcylation. Interestingly, T291N is a uterine carcinoma mutant in The Cancer Genome Atlas. Our biochemical assays demonstrate that T291A and T291N both increase PLK1 stability. Using stable H2B-GFP cells, we found that PLK1-T291A and PLK1-T291N mutants display chromosome segregation defects and result in misaligned and lagging chromosomes. In mouse xenograft models, we demonstrate that the O-GlcNAc-deficient PLK1-T291A and PLK1-T291N mutants enhance uterine carcinoma in animals. Hence, we propose that OGT partially exerts its mitotic function through O-GlcNAcylation of PLK1, which might be one mechanism by which elevated levels of O-GlcNAc promote tumorigenesis.

Comprehensive Study of Human FBXW7 Deleterious nsSNP's Functional Inference and Susceptibility to Gynaecological Cancer.

Cancer is one of the world's major causes of mortality, and it plays a most important role in the world's declining life expectancy. F-box and WD-40 domain protein 7 (FBXW7), a typical participant of the F-box family of proteins, has been considered as an anti-tumor protein and one of the maximum deregulated ubiquitin-proteasome system proteins in uterine carcinosarcoma, endometrial clear cell carcinoma and cervical carcinoma with the greatest prevalence of alterations. FBXW7 variants with known clinical significance, as well as non-synonymous single nucleotide polymorphisms (nsSNPs) in the F-Box and WD40 domains, were evaluated using functionality prediction web resources. Upon analysing the seventy-three deleterious nsSNP's impact on protein stability and function, we identified that forty-one nsSNPs of WD40 domain and three of F-Box domain imply decreased stability of the FBXW7 structure. Next to TP53 and PTEN, FBXW7 was reported with the highest percentage of arginine substitution among mutations related to cancer. The current research concentrated on two arginine residue locations (Arg465, Arg505) within the WD40-repeat domain, which is vital for substrate binding. Computational analysis revealed significant deviation in stability and structural configuration of mutants R505L, R465H, R465P, R505G, R505C, R465C, R505S and R505L structures. Protein-protein interaction network of FBXW7 populated with promising hub proteins NOTCH1, c-Myc, CCNE1, STYX, KLG5, SREB1, NFKB2, SKP1 and CUL1; thus, alteration in the FBXW7 leads to aberration in their signalling pathways as well as their substrate binding ability makes this protein as attractive target for personalized therapeutic intervention.

Histone deacetylase inhibition by suberoylanilide hydroxamic acid: a therapeutic approach to treat human uterine leiomyoma.

OBJECTIVE: To evaluate the effect of inhibition of histone deacetylases (HDACs) by suberoylanilide hydroxamic acid (SAHA) treatment of human uterine leiomyoma primary (HULP) cells in vitro on cell proliferation, cell cycle, extracellular matrix (ECM) formation, and transforming growth factor ß3 (TGF-ß3) signaling. DESIGN: Prospective study comparing uterine leiomyoma (UL) vs. adjacent myometrium (MM) tissue and cells with or without SAHA treatment. SETTING: Hospital and university laboratories. PATIENT(S): Women with UL without any hormone treatment. INTERVENTION(S): Myomectomy or hysterectomy surgery in women for leiomyoma disease. MAIN OUTCOME MEASURE(S): HDAC activity was assessed by enzyme-linked immunosorbent assay, and gene expression was assessed by quantitative real-time polymerase chain reaction. Effects of SAHA on HULP cells were analyzed by CellTiter (Promega, Madison, Wisconsin), Western blot, and quantitative real-time polymerase chain reaction. RESULT(S): The expression of HDAC genes (HDAC1, fold change [FC] = 1.65; HDAC3, FC = 2.08; HDAC6, FC = 2.42) and activity (0.56 vs. 0.10 optical density [OD]/h/mg) was significantly increased in UL vs. MM tissue. SAHA decreased HDAC activity in HULP cells but not in MM cells. Cell viability significantly decreased in HULP cells (81.68% at 5 µM SAHA, 73.46% at 10 µM SAHA), but not in MM cells. Proliferating cell nuclear antigen expression was significantly inhibited in SAHA-treated HULP cells (5 µM SAHA, FC = 0.556; 10 µM SAHA, FC = 0.622). Cell cycle markers, including C-MYC (5 µM SAHA, FC = 0.828) and CCND1 (5 µM SAHA, FC = 0.583; 10 µM SAHA, FC = 0.482), were significantly down-regulated after SAHA treatment. SAHA significantly inhibited ECM protein expression, including FIBRONECTIN (5 µM SAHA, FC = 0.815; 10 µM SAHA, FC = 0.673) and COLLAGEN I (5 µM SAHA, FC = 0.599; 10 µM SAHA, FC = 0.635), in HULP cells. TGFß3 and MMP9 gene expression was also significantly down-regulated by 10 µM SAHA (TGFß3, FC = 0.596; MMP9, FC = 0.677). CONCLUSION(S): SAHA treatment inhibits cell proliferation, cell cycle, ECM formation, and TGF-ß3 signaling in HULP cells, suggesting that histone deacetylation may be useful for treatment of UL.

Gene of the month: FH.

Fumarate hydratase (FH), encoded by the FH gene, is an enzyme which catalyses the conversion of fumarate to L-malate as part of the tricarboxylic acid cycle. Biallelic germline mutations in FH result in fumaric aciduria, a metabolic disorder resulting in severe neurological and developmental abnormalities. Heterozygous germline mutations in FH result in hereditary leiomyomatosis and renal cell carcinoma, a cancer predisposition syndrome. FH deficiency has multiple oncogenic mechanisms including through promotion of aerobic glycolysis, induction of pseudohypoxia, post-translational protein modification and impairment of DNA damage repair by homologous recombination. FH-deficient neoplasms can present with characteristic morphological features that raise suspicion for FH alterations and also frequently demonstrate loss of FH immunoreactivity and intracellular accumulation of 2-succinocysteine, also detected by immunohistochemistry.

Tryptophan catabolism is dysregulated in leiomyomas.

OBJECTIVE: To determine the expression and functional roles of indoleamine 2,3-dioxygenase 1 (IDO1) and tryptophan 2,3-dioxygenase (TDO2) in leiomyoma. DESIGN: Experimental study. SETTING: Academic research laboratory. PATIENT(S): Women undergoing hysterectomy for leiomyoma. INTERVENTION(S): Blockade of IDO1 and TDO2. MAIN OUTCOME MEASURE(S): Expression of IDO1 and TDO2 in leiomyoma and the effects of their inhibitors on the extracellular matrix. RESULT(S): Leiomyoma expressed significantly higher levels of IDO1 and TDO2 messenger ribonucleic acid (mRNA; 60.3%, 35/58 pairs and 98.3%, 57/58 pairs, respectively) and protein (54%, 27/50 pairs and 92%, 46/50 pairs, respectively) as well as the enzyme activity marker kynurenine (78.3%, 36/46 pairs for IDO1/TDO2) compared with levels in matched myometrium. The expression of TDO2 but not IDO1 mRNA was significantly higher in fibroids from African American compared with that in Caucasian and Hispanic patients. The TDO2 but not the IDO1 protein and mRNA levels were more abundant in fibroids bearing the MED12 mutation compared with results in wild-type leiomyomas. Treatment of leiomyoma smooth muscle cell and myometrial smooth muscle cell spheroids with the TDO2 inhibitor 680C91 but not the IDO1 inhibitor epacadostat significantly repressed cell proliferation and the expression of collagen type I (COL1A1) and type III (COL3A1) in a dose-dependent manner; these effects were more pronounced in leiomyoma smooth muscle cells compared with myometrial smooth muscle cell spheroids. CONCLUSION(S): These results underscore the physiological significance of the tryptophan degradation pathway in the pathogenesis of leiomyomas and the potential utility of anti-TDO2 drugs for treatment of leiomyomas.

Mechanical stiffness augments ligand-dependent progesterone receptor B activation via MEK 1/2 and Rho/ROCK-dependent signaling pathways in uterine fibroid cells.

OBJECTIVE: To test whether mechanical substrate stiffness would influence progesterone receptor B (PRB) signaling in fibroid cells. Uterine fibroids feature an excessive extracellular matrix, increased stiffness, and altered mechanical signaling. Fibroid growth is stimulated by progestins and opposed by anti-progestins, but a functional interaction between progesterone action and mechanical signaling has not been evaluated. DESIGN: Laboratory studies. SETTING: Translational science laboratory. PATIENT(S)/ANIMAL(S): Human fibroid cell lines and patient-matched fibroid and myometrial cell lines. INTERVENTION(S): Progesterone receptor B-dependent reporter assays and messenger RNA quantitation in cells cultured on stiff polystyrene plates (3GPa) or soft silicone plates (930KPa). Pharmacologic inhibitors of extracellular signal-related protein kinase (ERK) kinase 1/2 (MEK 1/2; PD98059), p38 mitogen-activated protein kinase (SB202190), receptor tyrosine kinases (RTKs; nintedanib), RhoA (A13), and Rho-associated coiled-coil kinase (ROCK; Y27632). MAIN OUTCOME MEASURE(S): Progesterone-responsive reporter activation. RESULT(S): Fibroid cells exhibited higher PRB-dependent reporter activity with progesterone (P4) in cells cultured on stiff vs. soft plates. Mechanically induced PRB activation with P4 was decreased 62% by PD98059, 78% by nintedanib, 38% by A13, and 50% by Y27632. Overexpression of the Rho-guanine nucleotide exchange factor (Rho-GEF), AKAP13, significantly increased PRB-dependent reporter activity. Collagen 1 messenger RNA levels were higher in fibroid cells grown on stiff vs. soft plates with P4. CONCLUSION(S): Cells cultured on mechanically stiff substrates had enhanced PRB activation via a mechanism that required MEK 1/2 and AKAP13/RhoA/ROCK signaling pathways. These studies provide a framework to explore the mechanisms by which mechanical stiffness affects progesterone receptor activation.

Phase II study of temozolomide monotherapy in patients with extrapulmonary neuroendocrine carcinoma.

Extrapulmonary neuroendocrine carcinoma (EPNEC) is a lethal disease with a poor prognosis. Platinum-based chemotherapy is used as the standard first-line treatment for unresectable EPNEC. Several retrospective studies have reported the results of the utilization of temozolomide (TMZ) as a drug for the second-line treatment for EPNEC. Patients with unresectable EPNEC that were resistant to platinum-based combination chemotherapy were recruited for a prospective phase II study of TMZ monotherapy. A 200 mg/m2 dose of TMZ was given from day 1 to day 5, every 4 weeks. Response rate (RR) was evaluated as the primary end-point. The presence of O6 -methylguanine DNA methyltransferase (MGMT) in EPNEC patients was also evaluated as exploratory research. Thirteen patients were enrolled in this study. Primary lesions were pancreas (n = 3), stomach (n = 3), duodenum (n = 1), colon (n = 1), gallbladder (n = 1), liver (n = 1), uterus (n = 1), bladder (n = 1), and primary unknown (n = 1). Each case was defined as pathological poorly differentiated neuroendocrine carcinoma from surgically resected and/or biopsied specimens. The median Ki-67 labeling index was 60% (range, 22%-90%). The RR was 15.4%, progression-free survival was 1.8 months (95% confidence interval [CI], 1.0-2.7), overall survival (OS) was 7.8 months (95% CI, 6.0-9.5), and OS from first-line treatment was 19.2 months (95% CI, 15.1-23.3). No grade 3 or 4 hematological toxicity had occurred and there was one case of grade 3 nausea. One case presented MGMT deficiency and this case showed partial response. Temozolomide monotherapy is a feasible, modestly effective, and safe treatment for patients with unresectable EPNEC following platinum-based chemotherapy, especially those with MGMT deficiency.

Mitochondrial DNA alterations underlie an irreversible shift to aerobic glycolysis in fumarate hydratase-deficient renal cancer.

Understanding the mechanisms of the Warburg shift to aerobic glycolysis is critical to defining the metabolic basis of cancer. Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is an aggressive cancer characterized by biallelic inactivation of the gene encoding the Krebs cycle enzyme fumarate hydratase, an early shift to aerobic glycolysis, and rapid metastasis. We observed impairment of the mitochondrial respiratory chain in tumors from patients with HLRCC. Biochemical and transcriptomic analyses revealed that respiratory chain dysfunction in the tumors was due to loss of expression of mitochondrial DNA (mtDNA)-encoded subunits of respiratory chain complexes, caused by a marked decrease in mtDNA content and increased mtDNA mutations. We demonstrated that accumulation of fumarate in HLRCC tumors inactivated the core factors responsible for replication and proofreading of mtDNA, leading to loss of respiratory chain components, thereby promoting the shift to aerobic glycolysis and disease progression in this prototypic model of glucose-dependent human cancer.

Neurofibrosarcoma Revisited: An Institutional Case Series of Uterine Sarcomas Harboring Kinase-related Fusions With Report of a Novel FGFR1-TACC1 Fusion.

Uterine sarcomas with variable CD34 and S100 expression represent an emerging class of tumor in the female genital tract which commonly presents in the endocervix of premenopausal women. Initial molecular characterization identified NTRK1 and NTRK3 gene fusions as oncogenic drivers in these tumors; however, the repertoire of genetic alterations is likely more diverse given the recent discovery of PDGFB and RET gene fusions in similarly described tumors. Importantly, these fusion events lead to the aberrant activation of kinases that are potentially therapeutically targetable; therefore, recognizing this class of tumor becomes critical for initiating the molecular testing required for an accurate diagnosis and identification of clinically actionable fusions. Here, we report our institutional experience with 12 cases of uterine spindle cell sarcomas harboring kinase-related fusions. Patients ranged from 21 to 80 years old (median, 38 y) and presented either asymptomatically or with pelvic pain and/or uterine bleeding. Eleven (92%; 11/12) tumors were localized to the cervix and 1 (8%; 1/12) tumor was localized in the anterior fundus of the uterine corpus. Tumors ranged in size from 1.5 to 15.0 cm (median, 6.0 cm) and were histologically characterized by a moderately cellular, infiltrative proliferation of spindle cells with features of benign gland entrapment, stromal collagen deposition, perivascular hyalinization, occasionally myxoid stroma, a lymphocytic infiltrate, occasional nuclear pseudoinclusions, and a pseudophyllodes architecture. RNA-sequencing identified NTRK1 (8/12), NTRK3 (1/12), and PDGFB (2/12) gene fusions, which have been previously implicated in this tumor class, as well as a novel FGFR1-TACC1 (1/12) fusion. All tumors in this cohort showed coexpression of CD34 and S100 by immunohistochemistry except for those tumors with PDGFB fusions which showed solely CD34 expression. Of the 10 surgically resected tumors with follow-up, outcomes best correlated with the stage of disease. One of 4 patients with stage IA tumors (1/4) had recurrences, half of the stage IB (2/4) tumors had recurrences and all of the stage IIB tumors (2/2) had recurrences and died of disease. Future studies are still required to better understand the spectrum of genetic alterations as well as evaluate the efficacy of targeted kinase inhibitors in this class of tumor.

Q192R variant in paraoxonase 1 gene confers susceptibility to leiomyoma.

OBJECTIVE: Paraoxonase 1 (PON1) plays a defensive role against oxidative stress by destroying oxidized lipids. Q192R single nucleotide polymorphism of PON1 gene alters the enzyme's activity. Several investigations reported a link between Q192R and an increased risk of developing tumors including uterine leiomyomas. We assessed the antioxidant effects of Q192R on myoma which fluctuate in frequency between populations. STUDY DESIGN: The cohort consisted of 68 unrelated uterine leiomyoma patients and 93 healthy controls that were randomly selected from women with no ultrasonographic evidence of myoma. MATERIALS AND METHODS: Genotyping was performed using tetra-primer amplification refractory mutation system-polymerase chain reaction. Chi-square test was selected to evaluate differences between the groups. RESULTS: To analyze the correlation between PON1 Q192R and leiomyoma risk, the AA genotype was given as a reference genotype then the two other genotypes were compared with the reference. A significantly (P < 0.05) increased risk of myoma was observed with both Q192R homozygote GG and heterozygote AG genotypes. The odds ratio (OR) of AG genotype was calculated 1.8 (confidence interval [CI]: 0.94-3.62). A higher OR was seen with GG genotype (OR: 2.8; 95% CI: 0.98-8.18). CONCLUSION: Oxidative stress has been suspected of having a link with tumor development, and the role of endogenous-free radical scavenger is taken into consideration. Increased protein oxidative stress status and reduced antioxidant capacity have been observed in leiomyomas patients. Our study indicates that the low-antioxidant PON1 R192 allele correlates to leiomyoma development.

Activation of protein kinase B by WNT4 as a regulator of uterine leiomyoma stem cell function.

OBJECTIVE: To investigate the functional interaction between the Wnt/ß-catenin and protein kinase B (Akt) pathways in leiomyoma stem cells (LSC). DESIGN: Laboratory study. SETTING: Research laboratory. PATIENT(S): Premenopausal women (n = 36; age range: 28 to 49 years) undergoing hysterectomy or myomectomy for leiomyoma. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Gene expression, protein phosphorylation, and cell proliferation. RESULT(S): Cells from human leiomyoma tissues were sorted by fluorescence-activated cell sorting (FACS) into three populations: LSC, intermediate cells (LIC), and differentiated cells (LDC) with the function of the Wnt/ß-catenin and Akt signaling pathways in leiomyoma cells evaluated using real-time quantitative polymerase chain reaction and immunoblot analyses. The Wnt/ß-catenin signaling pathway components were differentially expressed in each leiomyoma cell population. WNT4 was distinctly overexpressed in LIC, and its receptor FZD6 was primarily expressed in LSC. WNT4 stimulated Akt phosphorylation, activated ß-catenin, and increased primary leiomyoma cell proliferation. These stimulatory effects were abolished by cotreatment with the Akt inhibitor, MK-2206. WNT4 up-regulated the expression of pro-proliferative genes, c-Myc and cyclin D1, specifically in LSC; this was also abrogated by Akt inhibition. CONCLUSION(S): Our data suggest that WNT4 regulates LSC proliferation via Akt-dependent ß-catenin activation, representing a key step toward a better understanding of LSC regulation and potentially novel therapeutic targets.

Expression of alpha-methylacyl-CoA racemase in vaginal gastric-type adenocarcinoma and uterine clear cell carcinoma.

BACKGROUND: Alpha-methylacyl-coenzyme A racemase (AMACR, P504S) is a commonly used marker in immunohistochemical diagnosis of prostate cancer. Recent studies identified P504S markers of the clear cell histotype in the ovary and/or endometrium. Gastric-type adenocarcinoma (GAS) is difficult to diagnose histologically, particularly when there is crossover with clear cell carcinoma (CCC). However, the significance of P504S for differentially diagnosing GAS and CCC is unclear. AIM: To evaluate P504S as a potential diagnostic marker of GAS and CCC. SETTINGS AND DESIGN: We analyzed P504S expression in 48 cervical carcinomas (32 GAS and 16 CCC), as well as the expression of other markers including hepatocyte nuclear factor-1 beta (HNF-1ß) and NapsinA. MATERIAL AND METHODS: The expression differences of HNF-1ß, NapsinA, and P504S in GAS and CCC were detected by immunohistochemistry. Immunohistochemical histoscores based on the intensity and extent of staining were calculated. RESULTS: The positive rates of HNF-1ß in GAS and CCC were 90.32% and 75%, respectively. (χ2 = 2.251, P = 0.663). The positive rates of NapsinA in GAS and CCC were 19.36% and 81.25%, respectively. (χ2 = 47.332, P < 0.01). The positive rates of P504S in GAS and CCC were 16.13% and 81.25%, respectively. (χ2 = 41.420, P < 0.01). HNF-1ß was frequently expressed in GAS and CCC, while NapsinA and P504S were frequently expressed in CCC, and reduced or lost in GAS. CONCLUSION: NapsinA and P504S can be used to differentiate between GAS and CCC.

Quantitative proteomic analysis identifies novel regulators of methotrexate resistance in choriocarcinoma.

OBJECTIVE: Although methotrexate (MTX) is commonly used for the treatment of choriocarcinoma, chemoresistance to MTX may occur in a considerable fraction of patients. Further understanding on the mechanisms of MTX resistance would help to develop more effective therapy for choriocarcinoma. METHODS: Quantitative proteomic approach involving TMT labeling and LC-MS/MS was used to identify MTX resistance-related proteomic profiles in choriocarcinoma cell models. Pathway and process enrichment analysis were conducted to identify MTX resistance-related biological processes/molecular pathways. CCK-8 viability assay, clonogenic survival assay, and BrdU incorporation analysis were used to examine the chemosensitivity to MTX in choriocarcinoma cells. RESULTS: In total, 5704 protein groups were identified, among which 4997 proteins were quantified. Bioinformatic analysis revealed that multiple biological processes/molecular pathways might be associated with MTX resistance in JEG3/JEG3/MTX cell systems. DPP4 and METTL7A were selected for further investigation. Increased expression of DPP4 or METTL7A was observed in MTX-resistant cancer cell lines and choriocarcinoma tissues. Knockdown of DPP4 or METTL7A significantly decreased cell viability, impaired clonogenesis, and increased apoptosis after MTX treatment in JEG3/MTX and JAR/MTX cells; while over-expression of DPP4 or METTL7A promoted cell viability and reduced apoptosis following exposure to MTX in JEG3, JAR and BEWO cells. Further, DPP4 and METTL7A differentially activated prosurvival signaling pathways including PI3K/AKT, ERK1/2 and STAT3, and attenuated the accumulation of reactive oxygen species (ROS) in choriocarcinoma cell lines. CONCLUSIONS: DPP4 and METTL7A might promote MTX resistance through activating pro-survival signaling pathways and attenuating the accumulation of ROS in choriocarcinoma cells. Targeting DPP4 and METTL7A might be useful to sensitize choriocarcinoma cells to MTX-based chemotherapy.

Targeting Hedgehog Pathway and DNA Methyltransferases in Uterine Leiomyosarcoma Cells.

Uterine leiomyosarcoma (LMS) is an aggressive tumor that presents poor prognosis, high rates of recurrence and metastasis. Because of its rarity, there is no information available concerning LMS molecular mechanisms of origin and development. Here, we assessed the expression profile of Hedgehog (HH) signaling pathway markers and the effects of their pharmacological inhibition on uterine smooth muscle (UTSM), leiomyoma and LMS cells. Additionally, we also evaluated the effects of DNMTs inhibition on LMS cells behavior. Cell proliferation, migration and apoptosis rates were evaluated by MTT, Scratch and Annexin V assays, respectively. RNA expression and protein levels were assessed by qRT-PCR and Western blot. We found that SMO and GLIs (1, 2 and 3) expression was upregulated in LMS cells, with increased nuclear levels of GLI proteins. Treatment with LDE225 (SMOi) and Gant61 (GLIi) resulted in a significant reduction in Glis protein levels in LMS (p < 0.05). Additionally, the expression of DNMT (1, 3a, and 3b), as well as GLI1 nuclear expression, was significantly decreased after treatment with HH inhibitor in LMS cells. Our results showed that blocking of SMO, GLI and DNMTs is able to inhibit LMS proliferation, migration and invasion. Importantly, the combination of those treatments exhibited a potentiated effect on LMS malignant features due to HH pathway deactivation.

Prevalence of somatic and germline mutations of Fumarate hydratase in uterine leiomyomas from young patients.

AIMS: Hereditary leiomyomatosis and renal cell cancer (HLRCC) syndrome is caused by germline mutations in the Fumarate hydratase (FH) gene. In young women, the syndrome often presents with symptomatic uterine leiomyomas, leading to myomectomy or hysterectomy. In this study, we aimed to investigate the incidence and mutational profiles of FH-negative leiomyomas from young patients, thus allowing for early identification and triage of syndromic patients for surveillance. METHODS AND RESULTS: We evaluated 153 cases of uterine leiomyomas from women aged up to 30 years for loss of FH expression by tissue microarray (TMA)-based immunohistochemical staining. Mutational analysis of tumours with loss of FH was carried out by polymerase chain reaction (PCR) amplification of 10 exons within the FH gene and subsequent Sanger sequencing. The status of promoter methylation was assessed by bisulphite sequencing. Loss of FH protein expression was detected in seven (4.6%) of 153 tested uterine leiomyomas from young patients. All FH-negative leiomyomas displayed staghorn vasculature and fibrillary/neurophil-like cytoplasm. We found that six (86%) of seven FH-negative tumours detected by immunohistochemistry harboured FH mutations, 50% of which contained germline mutations. In particular, the germline mutational rate in FH gene was 2.0% (three of 153 cases). Bisulphite sequencing analysis failed to detect promoter methylation in any of the seven tumours. CONCLUSION: Our study showed a relatively high rate of FH germline mutation in FH-negative uterine leiomyomas from patients aged up to 30 years. While genetic mutations confer protein expression loss, epigenetic regulation of the FH gene appears to be unrelated to this phenotype.

Cross-talk between miR-29c and transforming growth factor-ß3 is mediated by an epigenetic mechanism in leiomyoma.

OBJECTIVE: To determine the expression of miR-29c and its target gene transforming growth factor-ß3 (TGF-ß3) in leiomyoma and the mechanisms of their reciprocal regulation. DESIGN: Experimental study. SETTING: Academic research laboratory. PATIENT(S): Women undergoing hysterectomy for leiomyoma. INTERVENTION(S): Overexpression and underexpression of miR-29c; blockade of DNA methyltransferase 1 (DNMT1). MAIN OUTCOME MEASURE(S): The miR-29c and its target gene TGF-ß3 in leiomyoma and the effects of TGF-ß3 and blockade of DNMT1 on miR-29c expression. RESULT(S): Leiomyoma expressed significantly lower levels of miR-29c, but higher expression of TGF-ß3 compared with matched myometrium. The expression of TGF-ß3 and miR-29c were independent of race/ethnicity. Using 3' untranslated region luciferase reporter assay we confirmed that TGF-ß3 is a direct target of miR-29c in leiomyoma smooth muscle cells (LSMCs). Gain-of-function of miR-29c in LSMCs inhibited the expression of TGF-ß3 at protein and messenger RNA levels, whereas loss-of-function of miR-29c had the opposite effect. Treatment of LSMCs with TGF-ß3 inhibited the expression of miR-29c, whereas it stimulated DNMT1 expression. Knockdown of DNMT1 through transfection with small interfering RNA significantly decreased the expression of TGF-ß3, and induced miR-29c expression. Knockdown of DNMT1 also attenuated the inhibitory effect of TGF-ß3 on miR-29c expression. Furthermore, we demonstrated that TGF-ß3 increased the methylation level of miR-29c promoter in LSMCs. CONCLUSION(S): There is an inverse relationship in the expression of TGF-ß3 and miR-29c in leiomyoma. The TGF-ß3 is a direct target of miR-29c and inhibits the expression of miR-29c through an epigenetic mechanism. The cross-talk between miR-29c and TGF-ß3 provides a feed forward mechanism of fibrosis in leiomyoma.

Paternal uniparental isodisomy of tyrosine hydroxylase locus at chromosome 11p15.4: spectrum of phenotypical presentations simulating hydatidiform moles.

Uniparental disomy is an abnormal genetic condition in which both homologous chromosomes or part of the chromosome are inherited from one parent and the other parent's homologous chromosome is lost. We report three cases of gestations with paternal uniparental isodisomy at tyrosine hydroxylase or TH01 locus on chromosome 11p15.4 identified by DNA genotyping. The patients' age ranged from 32 to 35 years and all patients presented with missed abortion during the first trimester. Abnormal chorionic villi were seen in all cases with histomorphological and/or p57 immunohistochemical features simulating either partial or complete mole. While two patients had an uneventful clinical course, one patient presented with clinical complications simulating persistent gestational trophoblastic disease/neoplasia that required multiagent chemotherapy with etoposide, methotrexate, actinomycin D, vincristine, and cyclophosphamide (EMA-CO). In summary, paternal uniparental isodisomy of tyrosine hydroxylase locus at chromosome 11p15.4 may result in an abnormal gestation that simulates a hydatidiform mole both clinically and histologically. The presence of abnormal trophoblastic proliferation combined with loss of p57 expression in villous cytotrophoblast and stromal cells may be associated with an aggressive clinical behavior.

Prospective Detection of Germline Mutation of Fumarate Hydratase in Women With Uterine Smooth Muscle Tumors Using Pathology-based Screening to Trigger Genetic Counseling for Hereditary Leiomyomatosis Renal Cell Carcinoma Syndrome: A 5-Year Single Institutional Experience.

Pathology-based screening of uterine smooth muscle tumors (uSMT) for morphology suggestive of fumarate hydratase deficiency (FH-d morphology) has been proposed as a method to identify women at increased risk for hereditary leiomyomatosis renal cell carcinoma (HLRCC) syndrome. For 5 years our clinical diagnostic practice has evaluated all women with any type of uSMT for FH-d morphology (defined, at low magnification, as staghorn shaped blood vessels and alveolar pattern edema and, at high magnification, as tumor macronucleoli surrounded by a halo and cytoplasmic eosinophilic globules) and, when present, used the pathology report to advise genetic counseling to further evaluate for HLRCC syndrome. We now report the results of this prospective screening strategy, with emphasis on the incidence and clinicopathologic features of FH-d morphology in uSMT, the rate of patient uptake of referral to genetic counseling, and the results of genetic testing for FH germline mutation. Among 2060 women with a uSMT, FH-d morphology was reported in 1.4% (30 women). Ten women elected to undergo FH genetic testing and 6 of 10 (60%) had a FH germline mutation: 5 were pathogenic mutations and 1 was a mutation variant of unknown significance. Therefore, the screening program led to a confirmed genetic diagnosis of HLRCC syndrome in 0.24% of all women with any type of uSMT. The women with a pathogenic mutation were ages 24 to 40 years. Although the majority of leiomyoma with bizarre nuclei exhibited FH-d morphology, the uSMT were conventional leiomyomas with FH-d morphology in 2 of 5 women found to have a pathogenic FH germline mutation. Relying on an abnormal FH immunostain result to trigger genetic counseling referral would have resulted in 2 of 5 (40%) cases with pathogenic FH germline mutation but normal FH immunoexpression going undetected, both of which were missense type mutations. There was no difference in the incidence of pathogenic FH germline mutation between FH-d morphology uSMT with an abnormal versus a normal FH immunostain result. Overall, this study demonstrates that prospective morphology-based screening, integrated with referral for genetic counseling, can result in the diagnosis of HLRCC syndrome in otherwise unselected women with uSMT. We conclude that this strategy should be incorporated in the routine pathologic examination of all uterine smooth muscle tumors.

ALK Is a Specific Diagnostic Marker for Inflammatory Myofibroblastic Tumor of the Uterus.

Inflammatory myofibroblastic tumor (IMT) is a myofibroblastic/fibroblastic neoplasm of intermediate malignant potential. It is frequently characterized by genetic fusion of ALK with a variety of partner genes, which results in the activated ALK signaling pathway that can be targeted with kinase inhibitors. IMTs can occur in the gynecologic tract, with the uterus (corpus and cervix) being the most frequent site. Recent studies suggest that IMTs in the gynecologic tract are underrecognized, and a low-threshold for performing ALK immunohistochemistry has been proposed. The aim of this study was to evaluate the specificity of ALK immunohistochemistry for IMTs among uterine mesenchymal and mixed epithelial/mesenchymal tumors. We performed ALK immunohistochemistry on 14 molecularly confirmed uterine IMTs and 260 other uterine pure mesenchymal and mixed epithelial/mesenchymal tumors. Cases showing any positive cytoplasmic and/or membranous staining of the tumor cells were considered to be ALK positive. All 14 IMTs were confirmed to harbor ALK genetic fusion by RNA sequencing, and ALK immunostaining in the form of granular cytoplasmic positivity with paranuclear accentuation was observed in all 14 cases. ALK was negative (complete absence of staining) in all the other pure mesenchymal tumors and in all mixed epithelial/mesenchymal tumors examined. Our findings show that ALK is a highly specific diagnostic immunohistochemical marker for ALK fusion in uterine mesenchymal tumors. In the work-up of uterine mesenchymal tumors, particularly smooth muscle tumors showing myxoid stromal changes, a diagnosis of IMT should be strongly considered if ALK positivity is observed.