Ovarian cancer cell fate regulation by the dynamics between saturated and unsaturated fatty acids.

Fatty acids are an important source of energy and a key component of phospholipids in membranes and organelles. Saturated fatty acids (SFAs) are converted into unsaturated fatty acids (UFAs) by stearoyl Co-A desaturase (SCD), an enzyme active in cancer. Here, we studied how the dynamics between SFAs and UFAs regulated by SCD impacts ovarian cancer cell survival and tumor progression. SCD depletion or inhibition caused lower levels of UFAs vs. SFAs and altered fatty acyl chain plasticity, as demonstrated by lipidomics and stimulated Raman scattering (SRS) microscopy. Further, increased levels of SFAs resulting from SCD knockdown triggered endoplasmic reticulum (ER) stress response with brisk activation of IRE1α/XBP1 and PERK/eIF2α/ATF4 axes. Disorganized ER membrane was visualized by electron microscopy and SRS imaging in ovarian cancer cells in which SCD was knocked down. The induction of long-term mild ER stress or short-time severe ER stress by the increased levels of SFAs and loss of UFAs led to cell death. However, ER stress and apoptosis could be readily rescued by supplementation with UFAs and reequilibration of SFA/UFA levels. The effects of SCD knockdown or inhibition observed in vitro translated into suppression of intraperitoneal tumor growth in ovarian cancer xenograft models. Furthermore, a combined intervention using an SCD inhibitor and an SFA-enriched diet initiated ER stress in tumors growing in vivo and potently blocked their dissemination. In all, our data support SCD as a key regulator of the cancer cell fate under metabolic stress and point to treatment strategies targeting the lipid balance.

Racial disparity in uterine leiomyoma: new insights of genetic and environmental burden in myometrial cells.

Uterine leiomyoma (LM), also known as uterine fibroids, are common gynecological tumors and can reach a prevalence of 70% among women by the age of 50 years. Notably, the LM burden is much higher in Black women with earlier onset, a greater tumor number, size, and severity compared to White women. Published knowledge shows that there are genetic, environmental, and lifestyle-based risk factors associated with racial disparity for LM. Significant strides have been made on genomic, epigenomic, and transcriptomic data levels in Black and White women to elucidate the underlying pathomolecular reasons of racial disparity in LM development. However, racial disparity of LM remains a major area of concern in gynecological research. This review highlights risk factors of LM and their role in different races. Furthermore, we discuss the genetics and uterine myometrial microenvironment in LM development. Comparative findings revealed that a major racial difference in the disease is linked to myometrial oxidative burden and altered ROS pathways which is relevant to the oxidized guanine in genomic DNA and MED12 mutations that drive the LM genesis. Considering the burden and morbidity of LM, we anticipate that this review on genetic risk and myometrial microenvironment will strengthen understanding and propel the growth of research to address the racial disparity of LM burden.

Racial differences in transcriptomics and reactive oxygen species burden in myometrium and leiomyoma.

STUDY QUESTION: Are there differences in Mediator Complex Subunit 12 mutations (MED12) mutation, transcriptomics, and protein expression in uterine myometrium and leiomyomas of Black and White women? SUMMARY ANSWER: RNA sequencing, tissue microarray, and immunohistochemistry data revealed that Black and White women have significant differences in their myometrium and leiomyoma profiles. WHAT IS KNOWN ALREADY: Black women develop uterine leiomyoma earlier than White women, and are more likely to be anemic, have multiple tumors, undergo hysterectomy at an earlier age, have a higher uterine weight, and report very severe pelvic pain. STUDY DESIGN, SIZE, DURATION: Uterine tissues were collected from premenopausal women undergoing hysterectomy or myomectomy at Northwestern University Prentice Women's Hospital (Chicago, IL) from 2010 to 2021. Tissues were collected from a total of 309 women, including from 136 Black women, 135 White women, and 38 women from other racial groups. A total of 529 uterine leiomyomas (290 from Black women, 184 from White women, and 55 from women of other racial groups) were subjected to molecular analysis. Leiomyoma and matched myometrium from a total of 118 cases including 60 Black women and 58 White women, were used for tissue microarrays, along with 34 samples of myometrium without leiomyoma from White women. PARTICIPANTS/MATERIALS, SETTING, METHODS: Tissues from the above patient cohorts were analyzed by tissue microarray, immunohistochemistry, RNA sequencing, and mutation analysis. MAIN RESULTS AND THE ROLE OF CHANCE: The results indicated that leiomyoma from Black women have a higher rate of MED12 mutations (79.0%) than those from White women (68.5%) (*P ≤ 0.05). RNA-sequencing analysis in myometrium revealed differentially expressed genes (270 upregulated, 374 downregulated) dependent on race, wherein reactive oxygen species, hypoxia, and oxidative phosphorylation pathways were positively correlated with samples derived from Black patients. The levels of proteins associated with oxidative DNA damage and repair, 8-hydroxyguanosine (8-OHdG), 8-oxoguanine glycosylase (OGG1), heme oxygenase-1 (HO-1), and kelch-like ECH-associated protein 1 (KEAP1), were higher in leiomyoma and matched myometrium, particularly those from Black patients, compared to the control myometrium (with leiomyoma) (***P ≤ 0.001). LARGE SCALE DATA: The datasets are available in the NCBI (The BioProject number: PRJNA859428). LIMITATIONS, REASONS FOR CAUTION: Myometrium without leiomyoma derived from White patients was used as a control in the tissue microarray analysis, as myometrium without leiomyoma from Black patients was not accessible in large numbers. The RNA sequencing was performed on myometrium tissue with leiomyoma present from 10 White and 10 Black women. However, one sample from a Black woman yielded low-quality RNA-sequencing data and was excluded from further analysis. WIDER IMPLICATIONS OF THE FINDINGS: Women with symptomatic leiomyomas have a considerable loss in their quality of life. This study provides information on underlying genetic and molecular defects that may be necessary for future therapeutics targeted at leiomyomas. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by grants from NCI (R01CA254367) and NICHD (P01HD057877). The authors declare no conflict of interest.

Borderline With Bad Behavior: An Unusual Low-grade Serous Carcinoma With Dedifferentiation From a Serous Borderline Tumor.

The pathogenesis of serous ovarian tumors has been extensively investigated, with a dualistic model dividing these cancers into 2 groups. Type I tumors, including low-grade serous carcinoma, is characteristic for concurrent presence of borderline tumors, less atypical cytology, relatively indolent biologic behavior, and molecular aberrations related to the MAPK pathway with chromosomal stability. Meanwhile, type II tumors, such as high-grade serous carcinoma, are notable for no significant association with borderline tumors, higher grade cytology, more aggressive biologic behavior, and TP53 mutations along with chromosomal instability. We describe a case of morphologic low-grade serous carcinoma with focally increased cytologic atypia arising in serous borderline tumors involving both ovaries, which demonstrated highly aggressive behavior despite several years of surgical and chemotherapeutic management. Each recurrent specimen contained more uniform higher grade morphology than what was seen in the original specimen. Immunohistochemical and molecular studies in both the original tumor and the most recent recurrence demonstrate identical mutations in the MAPK genes, but with additional mutations in the latter, notably an acquisition of a variant of possible clinical significance in the SMARCA4 gene, which is associated with dedifferentiation and aggressive biologic behavior. This case challenges our current and still evolving understanding of the pathogenesis, biologic behavior, and expected clinical outcome of low-grade serous ovarian carcinomas. It also underscores the need for further investigation into this complicated tumor.

Single-cell sequencing reveals novel cellular heterogeneity in uterine leiomyomas.

STUDY QUESTION: What are the cellular composition and single-cell transcriptomic differences between myometrium and leiomyomas as defined by single-cell RNA sequencing? SUMMARY ANSWER: We discovered cellular heterogeneity in smooth muscle cells (SMCs), fibroblast and endothelial cell populations in both myometrium and leiomyoma tissues. WHAT IS KNOWN ALREADY: Previous studies have shown the presence of SMCs, fibroblasts, endothelial cells and immune cells in myometrium and leiomyomas. However, there is no information on the cellular heterogeneity in these tissues and the transcriptomic differences at the single-cell level between these tissues. STUDY DESIGN, SIZE, DURATION: We collected five leiomyoma and five myometrium samples from a total of eight patients undergoing hysterectomy. We then performed single-cell RNA sequencing to generate a cell atlas for both tissues. We utilized our single-cell sequencing data to define cell types, compare cell types by tissue type (leiomyoma versus myometrium) and determine the transcriptional changes at a single-cell resolution between leiomyomas and myometrium. Additionally, we performed MED12-variant analysis at the single-cell level to determine the genotype heterogeneity within leiomyomas. PARTICIPANTS/MATERIALS, SETTING, METHODS: We collected five MED12-variant positive leiomyomas and five myometrium samples from a total of eight patients. We then performed single-cell RNA sequencing on freshly isolated single-cell preparations. Histopathological assessment confirmed the identity of the samples. Sanger sequencing was performed to confirm the presence of the MED12 variant in leiomyomas. MAIN RESULTS AND ROLE OF CHANCE: Our data revealed previously unknown heterogeneity in the SMC, fibroblast cell and endothelial cell populations of myometrium and leiomyomas. We discovered the presence of two different lymphatic endothelial cell populations specific to uterine leiomyomas. We showed that both myometrium and MED12-variant leiomyomas are relatively similar in cellular composition but differ in cellular transcriptomic profiles. We found that fibroblasts influence the leiomyoma microenvironment through their interactions with endothelial cells, immune cells and SMCs. Variant analysis at the single-cell level revealed the presence of both MED12 variants as well as the wild-type MED12 allele in SMCs of leiomyomatous tissue. These results indicate genotype heterogeneity of cellular composition within leiomyomas. LARGE SCALE DATA: The datasets are available in the NCBI Gene Expression Omnibus (GEO) using GSE162122. LIMITATIONS, REASONS FOR CAUTION: Our study focused on MED12-variant positive leiomyomas for single-cell RNA sequencing analyses. Leiomyomas carrying other genetic rearrangements may differ in their cellular composition and transcriptomic profiles. WIDER IMPLICATIONS FOR THE FINDINGS: Our study provides a cellular atlas for myometrium and MED12-variant positive leiomyomas as defined by single-cell RNA sequencing. Our analysis provides significant insight into the differences between myometrium and leiomyomas at the single-cell level and reveals hitherto unknown genetic heterogeneity in multiple cell types within human leiomyomas. Our results will be important for future studies into the origin and growth of human leiomyomas. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by funding from the National Institute of Child Health and Human Development (HD098580 and HD088629). The authors declare no competing interests.

Histological and molecular analysis of cellular leiomyoma with sclerosis: linked to HMGA2 overexpression.

HMGA2 overexpression is found in 10-15% of leiomyomas (LM). HMGA2 overexpression is common in variants of hydropic, intravenous and lipo-LM. Cellular or highly cellular LM (CLM) is a LM variant with a less well-defined molecular nature. In this study, we identified and examined 52 hypercellular LM with sclerotic collagen, herein defined as cellular leiomyoma with sclerosis (CLM-S). CLM-S shows large tumour size (average 12.2 cm) and characteristic histology of tumour cells, arranged in cellular fascicles, sheets and trabeculae with abundant dense, pink sclerotic extracellular matrix in bands and nodules and increased vascularity. Tumour cells are uniform with small, round-oval nuclei and scant, pale-eosinophilic to vacuolated cytoplasm reminiscent of pericytes. The differential diagnosis of CLM-S includes conventional CLM, endometrial stromal tumours and perivascular epithelioid cell tumour. Immunohistochemical profile [HMGA2, fumarate hydratase, smooth muscle markers, Melan A and HMB-45] and molecular alterations [by HMGA2 mRNA reverse transcription-polymerase chain reaction (RT-PCR), HMGA2 fluorescence in-situ hybridisation and MED12 sequencing] were analysed in comparison to matched myometrium and CLM controls. Remarkably, 96% (50 of 52) of CLM-S demonstrated diffuse positive immunoreactivity for HMGA2 and up to an 80-fold increase in HMGA2 mRNA, determined by RT-PCR. FISH analysis with break-part probes at intron 3 and the 5' UTR detected HMGA2 rearrangements in 47% (18 of 38) of CLM-S. All CLM-S retained expression of fumarate hydratase. No MED12 mutations were found in any CLM-S. Our findings show that CLM-S has unique and characteristic histomorphology probably driven by HMGA2 overexpression.

Uterine Leiomyosarcoma Associated With Leiomyoma With Bizarre Nuclei: Histology and Genomic Analysis of 2 Cases.

Leiomyoma with bizarre nuclei (LM-BN) is a rare variant of leiomyoma with overall benign clinical course. It has histologic features showing focal or diffuse nuclear atypia surrounded by usual type leiomyoma. Uterine leiomyosarcomas (LMS) are a group of rare and aggressive malignancies with limited treatment options available. The potential association between LM-BN with LMS is largely unknown. In this study, we report 2 cases of uterine smooth muscle tumor with typical histologic and molecular evidence of LM-BN, which are associated with its progression to the malignant counterpart of LMS. We summarize the detailed histologic, morphologic, and genomic characteristics of these 2 sets of cases. Our findings suggest that LMS progressing from preexisting LM-BN can be one of the tumor pathogenesis pathways in uterine leiomyosarcomas.

A role for WDR5 in integrating threonine 11 phosphorylation to lysine 4 methylation on histone H3 during androgen signaling and in prostate cancer.

Upon androgen stimulation, PKN1-mediated histone H3 threonine 11 phosphorylation (H3T11P) promotes AR target gene activation. However, the underlying mechanism is not completely understood. Here, we show that WDR5, a subunit of the SET1/MLL complex, interacts with H3T11P, and this interaction facilitates the recruitment of the MLL1 complex and subsequent H3K4 tri-methylation (H3K4me3). Using ChIP-seq, we find that androgen stimulation results in a 6-fold increase in the number of H3T11P-marked regions and induces WDR5 colocalization to one third of H3T11P-enriched promoters, thus establishing a genome-wide relationship between H3T11P and recruitment of WDR5. Accordingly, PKN1 knockdown or chemical inhibition severely blocks WDR5 chromatin association and H3K4me3 on AR target genes. Finally, WDR5 is critical in prostate cancer cell proliferation and is hyperexpressed in human prostate cancers. Together, these results identify WDR5 as a critical epigenomic integrator of histone phosphorylation and methylation and as a major driver of androgen-dependent prostate cancer cell proliferation.

Leiomyoma with nuclear atypia: Rare diseases that present a common diagnostic problem.

Leiomyoma with nuclear atypia describes a group of uterine smooth muscle tumors with a wide range of histologic and clinical presentations and remarkable nuclear atypia. These include fumarate hydratase-deficient leiomyoma (FH-LM), intravenous leiomyomatosis (IV-LM), and leiomyoma with bizarre nuclei (LM-BN). Other uterine mesenchymal tumors, such as perivascular epithelioid tumor (PEComa) and inflammatory myofibroblastic tumors (IMFT) are the mimickers of leiomyoma with nuclear atypia. LM-BN is the primary tumor model with a long history in gynecologic pathology, but the histogenesis of LM-BN remains largely unknown. Differentiating LM-BN from other benign variants, tumors with uncertain malignant potential (STUMP), or fully malignant leiomyosarcoma (LMS) can be diagnostically challenging. Recent progress has improved the diagnosis of many types of leiomyoma with nuclear atypia based on their specific histology and molecular alterations. LM-BN is now a diagnosis of exclusion. In this article, I review the history of leiomyoma with nuclear atypia and compare the clinical, histologic, and molecular features of LM-BN with those of its mimics. In particular, I highlight the current progress made in molecular genetics and pitfalls in the diagnosis of different myogenic tumors with nuclear atypia.

Integrated histologic and molecular analysis of uterine leiomyosarcoma and 2 benign variants with nuclear atypia.

Uterine leiomyosarcoma (LMS) is a rare but deadly disease. Due to poor understanding of the molecular and genetic causes of the disease, the diagnosis of LMS has been based primarily on histology. Nuclear atypia is one of hallmarks in LMS, however, it also occurs in 2 clinically benign variants, including smooth muscle tumors with fumarate hydratase alteration (SMT-FH) and leiomyoma with bizarre nuclei (LM-BN). In addition to nuclear atypia, many well recognized biomarkers used for LMS are also frequently overexpressed in LM-BN, and the histogenesis and molecular natures for LM-BN and LMS remain largely unknown. To characterize the molecular profiling of LMS, SMT-FH, and LM-BN, we performed integrated comprehensive genomic profiling including whole-genome sequencing (WGS) and RNA sequencing and genomic microarray analyses to assess genome-wide copy number alterations (CNAs) and immunohistochemistry (IHC) in all 3 tumor types. We found that both LM-BN and LMS showed genomic instability and harbored extensive CNAs throughout the whole genome. By contrast, the SMT-FH presented its characteristic 1q43-44 deletions in all cases tested, with minimal CNAs in the rest of genomic regions. Further analyses revealed that LMS and LM-BN groups showed similar patterns of CNAs that are tended to cluster together and separated from the SMT-FH group. The integrated molecular profiling enabled the detection of novel and traditional biomarkers and showed excellent discrimination between LM-BN and LMS. Our study suggests that LM-BN, despite having similar nuclear atypia to SMT-FH, showed similar genomic instability but distinct genomic alterations with its malignant counterpart of LMS. The integrated molecular profiling is of clinical importance in characterizing these rare uterine smooth muscle tumors.

Comparative analysis of AKT and the related biomarkers in uterine leiomyomas with MED12, HMGA2, and FH mutations.

Uterine leiomyomas (ULM) are histologically and molecularly heterogeneous and clinically they grow at vastly different rates. Several driver gene mutations have been identified in ULM, including MED12 mutations, HMGA2 overexpression, and biallelic FH inactivation. ULM with different driver mutant genes may use different molecular pathways, but currently no clear correlation between gene mutations and growth related pathways has been established. To better define this relationship, we collected ULM with MED12 (n = 25), HMGA2 (n = 15), and FH (n = 27) mutations and examined the sex steroid hormone, cell cycle, and AKT pathway genes by immunohistochemistry. While ER and PR were highly expressed in all types of ULM, FH ULM showed lower ER expression and higher PR expression. HMGA2 tumors had significantly higher levels of AKT signaling and mitogenic activity than other ULM types. HMGA2 activated AKT signaling through upregulation of IGF2BP2. Silencing HMGA2 in ULM cells resulted in downregulation of AKT and upregulation of p16 and p21, which eventually led to cell senescence. HMGA2 overexpression in ULM is not only related to tumor development but also plays a role in controlling cellular proliferation through the AKT pathway.

Application of ex-vivo spheroid model system for the analysis of senescence and senolytic phenotypes in uterine leiomyoma.

Cellular senecence is an important biologic endpoint. Naturally occuring (aging) senescence is common in uterine leiomyoma (ULM). AKT is one of major pathways in promoting ULM growth and survival. Inactivation of AKT by MK2206 in ULM resulted in stress-induced senescence in vitro. Study of the senescent phenotypes and molecular changes in ULM may greatly facilitate the understanding of the tumor biology and potential clinical therapy for this common disease associated with high morbidity. To study senescence in a model system that closely resembles primary ULM in vivo, we applied an ex vivo model of three-dimensional (3D) spheroid culture system which maintained the molecular and cellular characteristics of primary ULM and matched myometrium as seen in vivo. Gene expression profiling done on ULM induced to undergo replication (passaging) or stress-induced (MK2206) senescence revealed that ROS and hypoxic-related genes were upregulated in the two types of senescences. Overexpression of two selected genes, WIPI1 and SLITKR4, induced cellular senescence in ULM spheroids. Additionally, administration of ABT263 (a BH3 mimetic) effectively reduced the senescent cells induced in ULM spheroids. This study identified novel genes associated with senescence in ULM and demonstrated a BH3 mimetic to act as a senolytic to remove senescent cells.

Fumarate Hydratase Mutations and Alterations in Leiomyoma With Bizarre Nuclei.

Leiomyoma with bizarre nuclei (LM-BN), is a variant of uterine smooth muscle tumor with atypical histologic features. Although some LM-BN share several significant genetic alterations with leiomyosarcoma, including p16 and p53, the underlying tumorigenesis of LM-BN remains largely unknown. As we previously reported, LM-BN can be divided into 2 subtypes, type I and type II, based on different nuclear features. Type I LM-BN have similar histologic features as uterine smooth muscle tumors with fumarate hydratase (FH) alterations. In this study, we examined FH expression and FH mutations in 77 LM-BN (40 type I cases and 37 type II cases). FH expression was examined by immunohistochemistry using S-(2-succino)-cysteine antibodies (2SC, a protein modification associated with FH inactivation and subsequent fumarate accumulation) and FH antibodies (FH gene products). Seventy-two LM-BN tumors underwent Sanger sequencing to detect FH mutations. We found that 51% (39/77) of LM-BN showed FH alterations detected by immunohistochemistry with both 2SC and FH. Mutational analysis showed that 21% (15/72) of LM-BN harbored FH gene mutations. Further analysis revealed that 85% (34/40) of those with FH alterations were type I LM-BN while 19% (7/37) were type II LM-BN. Our findings suggest that over half of histologically diagnosed LM-BN may be related to FH alterations or FH mutations and the majority of these have the characteristic histologic features of type I LM-BN.

Synuclein-γ in uterine serous carcinoma impacts survival: An NRG Oncology/Gynecologic Oncology Group study.

BACKGROUND: Synuclein-γ (SNCG) is highly expressed in advanced solid tumors, including uterine serous carcinoma (USC). The objective of the current study was to determine whether SNCG protein was associated with survival and clinical covariates using the largest existing collection of USCs from the Gynecologic Oncology Group (GOG-8023). METHODS: High-density tissue microarrays (TMAs) of tumor tissues from 313 patients with USC were stained by immunohistochemistry for SNCG, p53, p16, FOLR1, pERK, pAKT, ER, PR, and HER2/neu. Associations of SNCG and other tumor markers with overall and progression-free survival were assessed using log-rank tests and Cox proportional-hazards models, which also were adjusted for age, race, and stage. RESULTS: The overall survival at 5 years was 46% for women with high SNCG expression and 62% for those with low SNCG expression (log-rank P = .021; hazard ratio [HR], 1.31; 95% confidence interval [CI], 0.91-1.9 in adjusted Cox model). The progression-free survival rate at 5 years was worse for women who had high SNCG expression, at 40%, compared with 56% for those who had low SNCG expression (log-rank P = .0081; HR, 1.36; 95% CI, 0.96-1.92 in adjusted Cox model). High levels of both p53 and p16 were significantly associated with worse overall survival (p53: HR, 4.20 [95% CI, 1.54-11.45]; p16: HR, 1.95 [95% CI, 1.01-3.75]) and progression-free survival (p53: HR, 2.16 [95% CI, 1.09-4.27]; p16: HR, 1.53 [95% CI, 0.87-2.69]) compared with low levels. CONCLUSIONS: This largest collection of USCs to date demonstrates that SNCG was associated with poor survival in univariate analyses. SNCG does not predict survival outcome independent of p53 and p16 in models that jointly consider multiple markers. Cancer 2017;123:1144-1155. © 2016 American Cancer Society.

Neferine induces autophagy of human ovarian cancer cells via p38 MAPK/ JNK activation.

Ovarian cancer is the most lethal gynecological malignancy. Patients usually have poor prognosis because of late diagnosis, relapse, and chemoresistance. It is pressing to seek novel agent for the treatment of ovarian cancer. Neferine is a bisbenzylisoquinoline alkaloid isolated from the embryos of lotus (Nelumbo nucifera). In this study, we investigated the antitumor effect of neferine on ovarian cancer cells. We found that neferine exhibited growth-inhibitory effect on human ovarian cancer cells, whereas showing less cytotoxic to non-malignant fallopian tube epithelial cells. Furthermore, we demonstrated that neferine induced autophagy and inactivated the mTOR pathway. Finally, we found that both p38 MAPK and JNK signaling pathways were activated by neferine treatment and contributed to the induction of autophagy in ovarian cancer cells. In conclusion, our findings showed that neferine induced autophagy of human ovarian cancer cells via p38 MAPK/JNK activation. Neferine may be explored as a promising antitumoral agent in ovarian cancer.

Atypical Leiomyoma With Features Suggesting of Fumarate Hydratase Mutation.

Individuals with germ line or somatic mutations of fumarate hydratase are predisposed to the development of leiomyomas of the skin and uterus. In this case report, we will describe the uterine smooth muscle tumors in a young patient who was originally diagnosed with ALM from a myomectomy specimen and experienced recurrence many years later. Tumor cells are diffusely immunoreactive for 2SC, suggestive of FH mutations.

Mutant p53 expression in fallopian tube epithelium drives cell migration.

Ovarian cancer is the fifth leading cause of cancer death among US women. Evidence supports the hypothesis that high-grade serous ovarian cancers (HGSC) may originate in the distal end of the fallopian tube. Although a heterogeneous disease, 96% of HGSC contain mutations in p53. In addition, the "p53 signature," or overexpression of p53 protein (usually associated with mutation), is a potential precursor lesion of fallopian tube derived HGSC suggesting an essential role for p53 mutation in early serous tumorigenesis. To further clarify p53-mutation dependent effects on cells, murine oviductal epithelial cells (MOE) were stably transfected with a construct encoding for the R273H DNA binding domain mutation in p53, the most common mutation in HGSC. Mutation in p53 was not sufficient to transform MOE cells but did significantly increase cell migration. A similar p53 mutation in murine ovarian surface epithelium (MOSE), another potential progenitor cell for serous cancer, was not sufficient to transform the cells nor change migration suggesting tissue specific effects of p53 mutation. Microarray data confirmed expression changes of pro-migratory genes in p53(R273H) MOE compared to parental cells, which could be reversed by suppressing Slug expression. Combining p53(R273H) with KRAS(G12V) activation caused transformation of MOE into high-grade sarcomatoid carcinoma when xenografted into nude mice. Elucidating the specific role of p53(R273H) in the fallopian tube will improve understanding of changes at the earliest stage of transformation. This information can help develop chemopreventative strategies to prevent the accumulation of additional mutations and reverse progression of the "p53 signature" thereby, improving survival rates.

Molecular analyses of 6 different types of uterine smooth muscle tumors: Emphasis in atypical leiomyoma.

BACKGROUND: Uterine smooth muscle tumors (USMTs) constitute a group of histologic, genetic, and clinical heterogeneous tumors that include at least 6 major histologically defined tumor types: leiomyoma (ULM), mitotically active leiomyoma (MALM), cellular leiomyoma (CLM), atypical leiomyoma (ALM), uncertain malignant potential (STUMP), and leiomyosarcoma (LMS). Apart from ULM and LMS, the nature of these variants is not well defined. METHODS: A total of 167 cases of different USMT variants were collected, reviewed, and diagnostically confirmed based on the World Health Organization and Stanford schemes. These included 38 cases of LMS, 18 cases of STUMP, 42 cases of ALM, 22 cases of CLM, 7 cases of MALM, and 40 cases of ULM. Molecular analysis included selected microRNAs (miRNAs), oncogenes, and tumor suppressors that are highly relevant to USMT. RESULTS: Overall, 49% (17/35) of LMS cases and 7% (1/14) of STUMP cases died due to their USMT, but no deaths were attributed to ALM. miRNA profiling revealed that ALM and LMS shared similar miRNA signatures. P53 mutations and PTEN deletions were significantly higher in LMS, ALM, and STUMP compared with other USMT variants (P < .01). In contrast, MED12 mutations were extremely common in ULM and MALM (> 74%) but were significantly less common (< 15%) in CLM, ALM, STUMP, and LMS (P < .01). CONCLUSION: Six types of USMT have different gene mutation fingerprints. ALM shares many molecular alterations with LMS. Our findings suggest that ALM may be a precursor lesion of LMS or have similar genetic changes during its early stage.

MED12 and HMGA2 mutations: two independent genetic events in uterine leiomyoma and leiomyosarcoma.

Recent identification of somatic MED12 mutations in most uterine leiomyomas brings a new venue for the study of the tumorigenesis of leiomyomas. We are particularly interested in the correlation of MED12 and HMGA2 gene products in leiomyomas and leiomyosarcomas with and without MED12 mutations. To address these issues, in this study we examined MED12 mutations in a large cohort of usual type leiomyomas (178 cases) and uterine leiomyosarcomas (32 cases). We found that 74.7% (133/178) of leiomyomas had MED12 mutations, which was consistent with several independent studies. In contrast, only 9.7% (3/32) of leiomyosarcomas harbored MED12 mutations. Expression analysis by western blot and immunohistochemistry revealed that those leiomyomas with complex MED12 mutations had significantly lower protein products than the matched myometrium. Interestingly, most leiomyosarcomas without MED12 mutations also had very low levels of MED12 expression in comparison to the matched myometrium. These findings suggest a potential functional role of MED12 in both benign and malignant uterine smooth muscle tumors. When we further examined HMGA2 expression in all leiomyomas and leiomyosarcomas, we found that HMGA2 overexpression was exclusively present in those leiomyomas with no MED12 mutation, accounting for 10.1% (18/178) of total leiomyomas and 40% (18/45) of non-MED12 mutant leiomyomas. Twenty-five percent (8/32) of leiomyosarcomas had HMGA2 overexpression, and no MED12 mutations were found in HMGA2 positive leiomyosarcoma. These findings strongly suggest that MED12 mutations and HMGA2 overexpression are independent genetic events that occur in leiomyomas, and they may act differently in the tumorigenesis of uterine leiomyomas.