Development of targeted therapy in uterine serous carcinoma, a biologically aggressive variant of endometrial cancer

Dysregulation of cell state dynamics during early stages of serous endometrial carcinogenesis

Serous endometrial carcinoma (SEC) constitutes about 10% of endometrial carcinomas and is one of the most aggressive and lethal types of uterine cancer. Due to the rapid progression of SEC, early detection of this disease is of utmost importance. However, molecular and cellular dynamics during the pre-dysplastic stage of this disease remain largely unknown. Here, we provide a comprehensive census of cell types and their states for normal, pre-dysplastic, and dysplastic endometrium in a mouse model of SEC. This model is associated with inactivation of tumor suppressor genes Trp53 and Rb1 , whose pathways are altered frequently in SEC. We report that pre-dysplastic changes are characterized by an expanded and increasingly diverse immature luminal epithelial cell populations. Consistent with transcriptome changes, cells expressing the luminal epithelial marker TROP2 begin to substitute FOXA2+ cells in the glandular epithelium. These changes are associated with a reduction in number and strength of predicted interactions between epithelial and stromal endometrial cells. By using a multi-level approach combining single-cell and spatial transcriptomics paired with screening for clinically relevant genes in human endometrial carcinoma, we identified a panel of 44 genes suitable for further testing of their validity as early diagnostic and prognostic markers. Among these genes are known markers of human SEC, such as C DKN2A, and novel markers, such as OAS2 and OASL, members of 2-5A synthetase family that is essential for the innate immune response. In summary, our results suggest an important role of the luminal epithelium in SEC pathogenesis, highlight aberrant cell-cell interactions in pre-dysplastic stages, and provide a new platform for comparative identification and characterization of novel, clinically relevant prognostic and diagnostic markers and potential therapeutic modalities.

In Vivo and In Vitro Efficacy of Trastuzumab Deruxtecan in Uterine Serous Carcinoma

Uterine serous carcinoma (USC) is a rare, biologically aggressive variant of endometrial cancer with a high recurrence rate and poor prognosis. HER2 overexpression (3+ positivity) by IHC and/or FISH ERBB2 gene amplification is detected in approximately one-third of patients with USC. Clinical trials incorporating trastuzumab with standard chemotherapy have recently demonstrated improved progression-free and overall survival in advanced-stage or recurrent USC that overexpresses HER2. However, a large number of patients with USC eventually developed resistance to trastuzumab. Trastuzumab deruxtecan (T-DXd) is a novel HER2-directed antibody-drug conjugate with a topoisomerase I inhibitor payload recently approved by the Food and Drug Administration (FDA) for multiple tumor indications. Here, we investigated the in vitro and in vivo efficacy of T-DXd in primary USC cell lines and xenografts with different HER2 expression. T-DXd-induced cell growth suppression in HER2-overexpressing cell lines in vitro, increased early and late apoptosis as assessed by annexin and propidium iodide staining, and, similarly to trastuzumab, T-DXd-induced significant antibody-dependent cellular cytotoxicity in the presence of peripheral blood lymphocytes. While negligible activity was detected against USC cell lines with low HER2 expression, T-DXd demonstrated significant bystander killing against USC tumors with low/negligible HER2 when such cells were admixed with HER2 3+ tumor cells in vitro. T-DXd showed tumor growth suppression in in vivo USC PDX models that overexpress HER2 at 3+ levels, prolonging survival when compared with controls, with minimal toxicity. Future clinical trials are warranted in patients with USC failing trastuzumab treatment.

HER2 Oncogene as Molecular Target in Uterine Serous Carcinoma and Uterine Carcinosarcoma

Uterine serous carcinoma (USC) and uterine carcinosarcoma (UCS) are two rare histologic variants of uterine carcinoma, with distinct molecular profiles and aggressive metastatic potential. As the effectivity of traditional platinum-based chemotherapy for USC and UCS is low, and there are high rates of resistance and recurrence, the development of novel targeted therapeutics is needed. Human epidermal growth factor receptor 2 (HER2) has proven to be an oncogene of increasing interest in these cancers, as HER2 protein overexpression and/or c-ERBB2 gene amplification ranges from ~30 to 35% in USC, and between ~15 and 20% in UCS. This review summarizes the existing clinical and preclinical evidence, as well as ongoing clinical trials of HER2-targeting therapeutics, and identifies potential areas of further development and inquiry.

Uterine serous carcinoma

Serous endometrial cancer represents a relative rare entity accounting for about 10% of all diagnosed endometrial cancer, but it is responsible for 40% of endometrial cancer-related deaths. Patients with serous endometrial cancer are often diagnosed at earlier disease stage, but remain at higher risk of recurrence and poorer prognosis when compared stage-for-stage with endometrioid subtype endometrial cancer. Serous endometrial cancers are characterized by marked nuclear atypia and abnormal p53 staining in immunohistochemistry. The mainstay of treatment for newly diagnosed serous endometrial cancer includes a multi-modal therapy with surgery, chemotherapy and/or radiotherapy. Unfortunately, despite these efforts, survival outcomes still remain poor. Recently, The Cancer Genome Atlas (TCGA) Research Network classified all endometrial cancer types into four categories, of which, serous endometrial cancer mostly is found within the "copy number high" group. This group is characterized by the increased cell cycle deregulation (e.g., CCNE1, MYC, PPP2R1A, PIKCA, ERBB2 and CDKN2A) and TP53 mutations (90%). To date, the combination of pembrolizumab and lenvatinib is an effective treatment modality in second-line therapy, with a response rate of 50% in advanced/recurrent serous endometrial cancer. Owing to the unfavorable outcomes of serous endometrial cancer, clinical trials are a priority. At present, ongoing studies are testing novel combinations of various targeted and immunotherapeutic agents in newly diagnosed and advanced/recurrent endometrial cancer - an important strategy for serous endometrial cancer, whereby tumors are usually p53+ and pMMR, making response to PD-1 inhibitor monotherapy unlikely. Here, the rare tumor working group (including members from the European Society of Gynecologic Oncology (ESGO), Gynecologic Cancer Intergroup (GCIG), and Japanese Gynecologic Oncology Group (JGOG)), performed a narrative review reporting on the current landscape of serous endometrial cancer and focusing on standard and emerging therapeutic options for patients affected by this difficult disease.

Genomics and splicing events of type II endometrial cancers in the black population: racial disparity, socioeconomic and geographical differences

Endometrial cancer, also known as uterine cancer, is the most common gynaecological malignancy with burgeoning incidence and mortality rates globally. Racial disparity, socioeconomic and geographical differences are important determinants of endometrial cancer incidence and mortality. Endometrial cancer is mainly categorised as type I and type II. Although less prevalent, type II is the most aggressive form of the disease and typically diagnosed at a late stage, contributing to higher mortality. Black women are at higher risk of developing aggressive, type II disease. Type I tumours are related to higher levels of circulating estrogen with lower-grade tumours that have a good prognosis and frequently related to PTEN mutations. In comparison, type II tumours are estrogen-independent, typically have poor prognosis and associated with the p53, HER2, PPP2R1A, FBXW7 and PIK3R1 mutations. The risk of developing type II malignancy is higher in women with Lynch syndrome as a result of mutations in the MMR gene family. Genetic modifications contribute to aberrant alternative splicing events that are related to tumour development, progression and resistance to therapy. Alternative splicing events are rapidly emerging as potential biomarkers and therapeutic targets. Type II endometrial cancer lacks targeted therapy and biomarkers for novel therapeutic strategies. Recent advances have illustrated a number of molecular targets that are currently explored for the treatment of advanced, late-stage endometrial cancer. The aim of this review is to outline 1) the epidemiology of type II endometrial cancer in black women, 2) discuss the correlated risk factors that contribute to the development of type II endometrial cancer and 3) the associated molecular mechanisms and genetic factors underlying the disease, and 4) aberrant splicing events and biomarkers with therapeutic potential as novel drug targets.

Learning common and specific patterns from data of multiple interrelated biological scenarios with matrix factorization

High-throughput biological technologies (e.g. ChIP-seq, RNA-seq and single-cell RNA-seq) rapidly accelerate the accumulation of genome-wide omics data in diverse interrelated biological scenarios (e.g. cells, tissues and conditions). Integration and differential analysis are two common paradigms for exploring and analyzing such data. However, current integrative methods usually ignore the differential part, and typical differential analysis methods either fail to identify combinatorial patterns of difference or require matched dimensions of the data. Here, we propose a flexible framework CSMF to combine them into one paradigm to simultaneously reveal Common and Specific patterns via Matrix Factorization from data generated under interrelated biological scenarios. We demonstrate the effectiveness of CSMF with four representative applications including pairwise ChIP-seq data describing the chromatin modification map between K562 and Huvec cell lines; pairwise RNA-seq data representing the expression profiles of two different cancers; RNA-seq data of three breast cancer subtypes; and single-cell RNA-seq data of human embryonic stem cell differentiation at six time points. Extensive analysis yields novel insights into hidden combinatorial patterns in these multi-modal data. Results demonstrate that CSMF is a powerful tool to uncover common and specific patterns with significant biological implications from data of interrelated biological scenarios.

PP2A: A Promising Biomarker and Therapeutic Target in Endometrial Cancer

Over the last decade, the use of targeted therapies has immensely increased in the treatment of cancer. However, treatment for endometrial carcinomas (ECs) has lagged behind, although potential molecular markers have been identified. This is particularly problematic for the type II ECs, since these aggressive tumors are usually not responsive toward the current standard therapies. Therefore, type II ECs are responsible for most EC-related deaths, indicating the need for new treatment options. Interestingly, molecular analyses of type II ECs have uncovered frequent genetic alterations (up to 40%) in PPP2R1A, encoding the Aα subunit of the tumor suppressive heterotrimeric protein phosphatase type 2A (PP2A). PPP2R1A mutations were also reported in type I ECs and other common gynecologic cancers, albeit at much lower frequencies (0-7%). Nevertheless, PP2A inactivation in the latter cancer types is common via other mechanisms, in particular by increased expression of Cancerous Inhibitor of PP2A (CIP2A) and PP2A Methylesterase-1 (PME-1) proteins. In this review, we discuss the therapeutic potential of direct and indirect PP2A targeting compounds, possibly in combination with other anti-cancer drugs, in EC. Furthermore, we investigate the potential of the PP2A status as a predictive and/or prognostic marker for type I and II ECs.

Targeted Therapies in Type II Endometrial Cancers: Too Little, but Not Too Late

Type II endometrial carcinomas (ECs) are responsible for most endometrial cancer-related deaths due to their aggressive nature, late stage detection and high tolerance for standard therapies. However, there are no targeted therapies for type II ECs, and they are still treated the same way as the clinically indolent and easily treatable type I ECs. Therefore, type II ECs are in need of new treatment options. More recently, molecular analysis of endometrial cancer revealed phosphorylation-dependent oncogenic signalling in the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) pathways to be most frequently altered in type II ECs. Consequently, clinical trials tested pharmacologic kinase inhibitors targeting these pathways, although mostly with rather disappointing results. In this review, we highlight the most common genetic alterations in type II ECs. Additionally, we reason why most clinical trials for ECs using targeted kinase inhibitors had unsatisfying results and what should be changed in future clinical trial setups. Furthermore, we argue that, besides kinases, phosphatases should no longer be ignored in clinical trials, particularly in type II ECs, where the tumour suppressive phosphatase protein phosphatase type 2A (PP2A) is frequently mutated. Lastly, we discuss the therapeutic potential of targeting PP2A for (re)activation, possibly in combination with pharmacologic kinase inhibitors.

Expression of Estrogen Receptors (ER), Progesterone Receptors (PR) and HER-2/neu receptors in Endometrial Carcinoma and their associations with histological types, grades and stages of the tumor

Objective:

To study and detect immunohistochemical expression of Estrogen Receptors, Progestrone Receptors and HER-2/neu Receptors in Endometrial Carcinoma (EC) and to find their associations with histological types, grades and stages of the tumor.

Methods:

A cross sectional study of one year duration from January 2016 to January 2017 was conducted at Histopathology department of Army Medical College, Rawalpindi. A non-probability purposive sampling technique was used to include 56 cases of EC. The specimens were tested for ER, PR and HER-2/neu expression using immunohistochemical analysis. Data was analyzed in SPSS and the significance of association of expression of the receptors with histological types, grades and stages of the tumor was assessed.

Results:

Significant association of Her-2/neu overexpression with histological types and grades of EC was seen, whereas the association of ER and PR expression with histological types, grades and stage of EC was statistically insignificant.

Conclusion:

It is suggested that EC showing over expression of HER2/neu with immunohistochemistry may be treated with anti HER-2/neu treatment with better chances of survival and decreased post-treatment morbidity.

A rare case of endometrial cancer metastatic to the uveal choroid

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Choroid metastases are extremely rare in endometrial cancer.

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Choroid metastases can present as many different eye complaints.

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Comprehensive eye exams are important in patients with visual complaints.

Improved i.p. drug delivery with bioadhesive nanoparticles

The i.p. administration of chemotherapy in ovarian and uterine serous carcinoma patients by biodegradable nanoparticles may represent a highly effective way to suppress peritoneal carcinomatosis. However, the efficacy of nanoparticles loaded with chemotherapeutic agents is currently hampered by their fast clearance by lymphatic drainage. Here, we show that a unique formulation of bioadhesive nanoparticles (BNPs) can interact with mesothelial cells in the abdominal cavity and significantly extend the retention of the nanoparticles in the peritoneal space. BNPs loaded with a potent chemotherapeutic agent [epothilone B (EB)] showed significantly lower systemic toxicity and higher therapeutic efficacy against i.p. chemotherapy-resistant uterine serous carcinoma-derived xenografts compared with free EB and non-BNPs loaded with EB.

Mutational landscape of uterine and ovarian carcinosarcomas implicates histone genes in epithelial-mesenchymal transition

Carcinosarcomas (CSs) of the uterus and ovary are highly aggressive neoplasms containing both carcinomatous and sarcomatous elements. We analyzed the mutational landscape of 68 uterine and ovarian CSs by whole-exome sequencing. We also performed multiregion whole-exome sequencing comprising two carcinoma and sarcoma samples from six tumors to resolve their evolutionary histories. The results demonstrated that carcinomatous and sarcomatous elements derive from a common precursor having mutations typical of carcinomas. In addition to mutations in cancer genes previously identified in uterine and ovarian carcinomas such as TP53, PIK3CA, PPP2R1A, KRAS, PTEN, CHD4, and BCOR, we found an excess of mutations in genes encoding histone H2A and H2B, as well as significant amplification of the segment of chromosome 6p harboring the histone gene cluster containing these genes. We also found frequent deletions of the genes TP53 and MBD3 (a member with CHD4 of the nucleosome remodeling deacetylase complex) and frequent amplification of chromosome segments containing the genes PIK3CA, TERT, and MYC Stable transgenic expression of H2A and H2B in a uterine serous carcinoma cell line demonstrated that mutant, but not wild-type, histones increased expression of markers of epithelial-mesenchymal transition (EMT) as well as tumor migratory and invasive properties, suggesting a role in sarcomatous transformation. Comparison of the phylogenetic relationships of carcinomatous and sarcomatous elements of the same tumors demonstrated separate lineages leading to these two components. These findings define the genetic landscape of CSs and suggest therapeutic targets for these highly aggressive neoplasms.

Improved i.p. drug delivery with bioadhesive nanoparticles

The i.p. administration of chemotherapy in ovarian and uterine serous carcinoma patients by biodegradable nanoparticles may represent a highly effective way to suppress peritoneal carcinomatosis. However, the efficacy of nanoparticles loaded with chemotherapeutic agents is currently hampered by their fast clearance by lymphatic drainage. Here, we show that a unique formulation of bioadhesive nanoparticles (BNPs) can interact with mesothelial cells in the abdominal cavity and significantly extend the retention of the nanoparticles in the peritoneal space. BNPs loaded with a potent chemotherapeutic agent [epothilone B (EB)] showed significantly lower systemic toxicity and higher therapeutic efficacy against i.p. chemotherapy-resistant uterine serous carcinoma-derived xenografts compared with free EB and non-BNPs loaded with EB.

Inferring pathway dysregulation in cancers from multiple types of omic data

Although in some cases individual genomic aberrations may drive disease development in isolation, a complex interplay among multiple aberrations is common. Accordingly, we developed Gene Set Omic Analysis (GSOA), a bioinformatics tool that can evaluate multiple types and combinations of omic data at the pathway level. GSOA uses machine learning to identify dysregulated pathways and improves upon other methods because of its ability to decipher complex, multigene patterns. We compare GSOA to alternative methods and demonstrate its ability to identify pathways known to play a role in various cancer phenotypes. Software implementing the GSOA method is freely available from https://bitbucket.org/srp33/gsoa.

Dual HER2 targeting impedes growth of HER2 gene-amplified uterine serous carcinoma xenografts

PURPOSE

Uterine serous carcinoma (USC) is an aggressive subtype of endometrial cancer that commonly harbors HER2 gene amplification. We investigated the effectiveness of HER2 inhibition using lapatinib and trastuzumab in vitro and in xenografts derived from USC cell lines and USC patient-derived xenografts.

EXPERIMENTAL DESIGN

Immunohistochemistry and FISH were performed to assess HER2 expression in 42 primary USC specimens. ARK1, ARK2, and SPEC2 cell lines were treated with trastuzumab or lapatinib. Cohorts of mice harboring xenografts derived from ARK2 and SPEC2 cell lines and EnCa1 and EnCa2 primary human USC samples were treated with either vehicle, trastuzumab, lapatinib, or the combination of trastuzumab and lapatinib. Acute and chronic posttreatment tumor samples were assessed for downstream signaling alterations and examined for apoptosis and proliferation.

RESULTS

HER2 gene amplification (24%) correlated significantly with HER2 protein overexpression (55%). All models were impervious to single-agent trastuzumab treatment. Lapatinib decreased in vitro proliferation of all cell lines and in vivo growth of HER2-amplified xenografts (ARK2, EnCa1). In addition, dual therapy with trastuzumab and lapatinib resulted in significant antitumor activity only in ARK2 and EnCa1 tumors. Dual HER2 therapy induced on target alteration of downstream MAPK and PI3K pathway mediators only in HER2-amplified models, and was associated with increased apoptosis and decreased proliferation.

CONCLUSIONS

Although trastuzumab alone did not impact USC growth, dual anti-HER2 therapy with lapatinib led to improved inhibition of tumor growth in HER2-amplified USC and may be a promising avenue for future investigation.

HER2/neu in Endometrial Cancer: A Promising Therapeutic Target With Diagnostic Challenges

CONTEXT

In the era of targeted cancer therapy, there is growing interest in developing novel therapeutic strategies against endometrial carcinoma, especially its most biologically aggressive variant, serous adenocarcinoma. Several publications have demonstrated that a significant proportion of uterine serous carcinomas show HER2 overexpression and/or amplification, suggesting that HER2 may be a promising therapeutic target. Case reports have already shown clinical response to trastuzumab, a humanized monoclonal immunoglobulin (Ig) G1 antibody against HER2, and patients are currently being enrolled in a multi-institutional prospective randomized trial to evaluate the therapeutic efficacy of trastuzumab.

OBJECTIVE

To review current data on HER2 testing and targeted therapy against HER2/neu in endometrial carcinoma.

DATA SOURCES

Review of the literature and personal experience of the authors.

CONCLUSIONS

Parallel to the clinical studies, there is a need to develop standardized criteria for HER2 testing in endometrial carcinoma that reflect the unique biological and pathogenetic features of these tumors and correlate with clinical response to therapy. This article presents a comprehensive review of the current state of HER2-based therapy and HER2 testing in endometrial carcinoma.

Toward standard HER2 testing of endometrial serous carcinoma: 4-year experience at a large academic center and recommendations for clinical practice

HER2 overexpression and/or amplification have been reported in endometrial serous carcinoma, suggesting that HER2 may be a promising therapeutic target. However, there is considerable variation in the reported rates of HER2 overexpression and amplification, likely--at least in part--resulting from variability in the testing methods, interpretation, and scoring criteria used. Unlike in breast and gastric cancer, currently there are no established guidelines for HER2 testing in endometrial carcinoma. A total of 108 endometrial carcinoma cases--85 pure serous carcinomas and 23 mixed endometrial carcinomas with serous component--were identified over a 4-year period. All H&E and HER2 immunohistochemical slides were reviewed and HER2 FISH results (available on 52 cases) were retrieved from pathology reports. HER2 immunohistochemical scores were assigned according to the FDA criteria and the current breast ASCO/CAP scoring criteria. Clinical information was retrieved from the patients' medical records. Thirty-eight cases (35%) showed HER2 overexpression and/or gene amplification, 20 of which (53%) had significant heterogeneity of protein expression by immunohistochemistry. Lack of apical membrane staining resulting in a lateral/basolateral staining pattern was observed in the majority of HER2-positive tumors. Five of the HER2-positive cases (13%) demonstrated discrepant immunohistochemical scores when using the FDA versus ASCO/CAP scoring system. The overall concordance rate between HER2 immunohistochemistry and FISH was 75% (39/52) when using the FDA criteria, compared with 81% (42/52) by the ASCO/CAP scoring system. In conclusion, in this largest comprehensive study, 35% of endometrial serous carcinoma harbors HER2 protein overexpression and/or gene amplification, over half of which demonstrate significant heterogeneity of protein expression. The current breast ASCO/CAP scoring criteria provide the highest concordance between immunohistochemistry and FISH. Assessment of HER2 immunohistochemistry on multiple tumor sections or sections with large tumor areas is recommended, due to the significant heterogeneity of HER2 protein expression.

The emerging genomic landscape of endometrial cancer

BACKGROUND

Endometrial cancer is responsible for approximately 74 000 deaths annually among women worldwide. It is a heterogeneous disease comprising multiple histologic subtypes. In the US, the majority of deaths from endometrial carcinoma are attributed to the serous and endometrioid subtypes. An understanding of the fundamental genomic alterations that drive serous and endometrioid endometrial carcinomas lays the foundation for the identification of molecular markers that could improve the clinical management of patients presenting with these tumors.

CONTENT

We review the current state of knowledge regarding somatic genomic alterations that occur in serous and endometrioid endometrial tumors. We present this knowledge in a historical context by reviewing the genomic alterations that studies of individual genes and proteins have identified over the past 2 decades or so. We then review very recent comprehensive and systematic surveys of genomic, exomic, transcriptomic, epigenomic, and proteomic alterations in serous and endometrioid endometrial carcinomas.

SUMMARY

The recent mapping of the genomic landscape of serous and endometrioid endometrial carcinomas has produced the first comprehensive molecular classification of these tumors, which has distinguished 4 molecular subgroups: a POLE [polymerase (DNA directed), ε, catalytic subunit] ultramutated subgroup, a hypermutated/microsatellite-unstable subgroup, a copy number-low/microsatellite-stable subgroup, and a copy number-high subgroup. This molecular classification may ultimately serve to refine the diagnosis and treatment of women with endometrioid and serous endometrial tumors.

Expression and potential role of ErbB receptors in type II endometrial cancer

OBJECTIVE

Endometrial cancer is the most common malignancy of the female genital tract. Based on clinical and pathological features, endometrial cancer is classified into two types. The aim of our study was to describe the expression and the potential clinical role of ErbB receptors in Greek patients with type II endometrial cancer.

STUDY DESIGN

Between 1991 and 2008, 10 women with histologically confirmed type II endometrial cancer were referred to the Department of Gynecologic Oncology of the University of Patras Medical School. Tissue specimens from endometrial lesions were immunostained for EGFR, ErbB-2, ErbB-3 and ErbB-4.

RESULTS

For EGFR, 5 cases were positive (50%) and 5 cases were negative. For ErbB-2, 9 cases were positive (90%) and 1 case was negative. For ErbB-3, all cases were positive. For ErbB-4, 7 cases were positive (70%) and 3 cases were negative. Also for all ErbB receptors, 5 cases were positive (50%). During follow up, 3 patients died from their disease. All of them had papillary serous endometrial cancer and 2 of them were positive for all ErbB receptors.

CONCLUSION

Although our study was based on a small number of cases, it is obvious that we had high expression levels of ErbB receptors in patients with type II endometrial cancer. Also the majority of patients with dismal outcome were positive for all ErbB receptors. This is very important, as ErbB-targeted therapies may be clinically active as adjuvant therapy in well-defined subgroups of type II EC patients with EGFR and ErbB-2 overexpression.

Landscape of somatic single-nucleotide and copy-number mutations in uterine serous carcinoma

Uterine serous carcinoma (USC) is a biologically aggressive subtype of endometrial cancer. We analyzed the mutational landscape of USC by whole-exome sequencing of 57 cancers, most of which were matched to normal DNA from the same patients. The distribution of the number of protein-altering somatic mutations revealed that 52 USC tumors had fewer than 100 (median 36), whereas 5 had more than 3,000 somatic mutations. The mutations in these latter tumors showed hallmarks of defects in DNA mismatch repair. Among the remainder, we found a significantly increased burden of mutation in 14 genes. In addition to well-known cancer genes (i.e., TP53, PIK3CA, PPP2R1A, KRAS, FBXW7), there were frequent mutations in CHD4/Mi2b, a member of the NuRD-chromatin-remodeling complex, and TAF1, an element of the core TFIID transcriptional machinery. Additionally, somatic copy-number variation was found to play an important role in USC, with 13 copy-number gains and 12 copy-number losses that occurred more often than expected by chance. In addition to loss of TP53, we found frequent deletion of a small segment of chromosome 19 containing MBD3, also a member of the NuRD-chromatin-modification complex, and frequent amplification of chromosome segments containing PIK3CA, ERBB2 (an upstream activator of PIK3CA), and CCNE1 (a target of FBXW7-mediated ubiquitination). These findings identify frequent mutation of DNA damage, chromatin remodeling, cell cycle, and cell proliferation pathways in USC and suggest potential targets for treatment of this lethal variant of endometrial cancer.

Early stage uterine serous carcinoma: management updates and genomic advances

OBJECTIVE

Even in cases of early stage disease, uterine serous carcinoma (USC) is associated with high recurrence rates and a disproportionate number of cancer-related deaths. Prospective data to guide therapy for women with this disease are limited. This article reviews the currently available literature regarding optimal management of women with early stage USC.

METHODS

MEDLINE was searched for all research articles published in the English language from January 1, 1996 through October 30, 2012 in which the studied population included women diagnosed with early stage USC. Although preference was given to prospective studies, studies were not limited by design or numbers of patients in light of the relative paucity of the available literature.

RESULTS

Early stage USC (Stages I-II) is associated with a risk of recurrence that ranges from 0 to 80%, and is related to the amount of residual uterine disease, cervical involvement and adjuvant therapy. Treatment with platinum and taxane-based chemotherapy may decrease the risk of recurrence and may improve survival outcomes; volume directed radiotherapy may also be of benefit. USC highly expresses HER2/neu, a promising and rational target for biologic therapy. Alterations in the PIK3CA/AKT/ mTOR pathway are also of relevance and offer other potential therapeutic targets.

CONCLUSIONS

USC is a unique and biologically aggressive subtype of endometrial cancer, and as such, should be studied as a distinct entity. Prospective trials incorporating traditional chemotherapeutics and radiation as well as targeted therapies are warranted to define the optimal management approach for women with this disease.

Downregulation of membrane complement inhibitors CD55 and CD59 by siRNA sensitises uterine serous carcinoma overexpressing Her2/neu to complement and antibody-dependent cell cytotoxicity in vitro: implications for trastuzumab-based immunotherapy

Background:

We evaluated the expression of CD46, CD55 and CD59 membrane-bound complement-regulatory proteins (mCRPs) in primary uterine serous carcinoma (USC) and the ability of small interfering RNA (siRNA) against these mCRPs to sensitise USC to complement-dependent cytotoxicity (CDC) and antibody (trastuzumab)-dependent cellular cytotoxicity (ADCC) in vitro.

Methods:

Membrane-bound complement-regulatory proteins expression was evaluated using real-time PCR (RT–PCR) and flow cytometry, whereas Her2/neu expression and c-erbB2 gene amplification were assessed using immunohistochemistry, flow cytometry and fluorescent in-situ hybridisation. The biological effect of siRNA-mediated knockdown of mCRPs on HER2/neu-overexpressing USC cell lines was evaluated in CDC and ADCC 4-h chromium-release assays.

Results:

High expression of mCRPs was found in USC cell lines when compared with normal endometrial cells (P<0.05). RT–PCR and FACS analyses demonstrated that anti-mCRP siRNAs were effective in reducing CD46, CD55 and CD59 expression on USC (P<0.05). Baseline complement-dependent cytotoxicity (CDC) against USC cell lines was low (mean±s.e.m.=6.8±0.9%) but significantly increased upon CD55 and CD59 knockdown (11.6±0.8% and 10.7±0.9%, respectively, P<0.05). Importantly, in the absence of complement, both CD55 and CD59, but not CD46, knockdowns significantly augmented ADCC against USC overexpressing Her2/neu.

Conclusion:

Uterine serous carcinoma express high levels of the mCRPs CD46, CD55 and CD59. Small interfering RNA inhibition of CD55 and CD59, but not CD46, sensitises USC to both CDC and ADCC in vitro, and if specifically targeted to tumour cells, may significantly increase trastuzumab-mediated therapeutic effect in vivo.