Biomarkers as prognostic factors in endometrial cancer

Endometrial cancer is the most common gynecologic malignancy in more developed countries. Approximately 75% of cases are diagnosed at an early stage with a tumor confined to the uterine corpus. Although most patients are cured by surgery alone, about 15-20% with no signs of locally advanced or metastatic disease at primary treatment recurs, with limited responsiveness to systemic therapy. The most common basis for determining the risk of recurrent disease has been classification of endometrial cancers into two subtypes. Type I, associated with a good prognosis and endometrioid histology and type II, associated with a poor prognosis and non-endometrioid histology. This review will focus primarily on the molecular biomarkers that have supported the dualistic model of endometrial carcinoma and help determine which patients would benefit from either adjuvant therapy or more aggressive primary treatment.     

Carcinoma of the Lower Uterine Segment (LUS): Clinicopathological Characteristics and Association with Lynch Syndrome

Endometrial cancer arises from the uterine body and fundus in many cases, but can also originate from the lower region of the uterine body through the upper region of the cervix. Such tumors are referred to as carcinoma of the lower uterine segment (LUS) or isthmus, and account for 3-6.3% of all cases of endometrial cancer. This relatively low incidence has permitted performance of only small-scale studies, but the clinical and pathological characteristics of carcinoma of the LUS in all these reports have differed from those of other endometrial cancers. Generally, endometrial cancer is classified into estrogen-dependent endometrioid adenocarcinoma (designated as type I), and non-endometrioid types that are less associated with estrogen and include poorly differentiated adenocarcinoma (type II). In some reports, carcinoma of the LUS has been found to have type II characteristics. Carcinoma of the LUS has also been associated with Lynch syndrome, a hereditary disease with frequent development of colorectal, endometrial, and ovarian cancers. Lynch syndrome is thought to be induced by mismatch repair gene mutation. The frequency of Lynch syndrome in cases of general endometrial cancer is 1-2%. In contrast, the frequency in patients with carcinoma of the LUS is much higher, with up to 29% of cases diagnosable with Lynch syndrome and a high frequency of hMSH2 mutation found in one study. This suggests that further investigation of the clinical and pathological characteristics of carcinoma of the LUS and the association with Lynch syndrome is required through performance of a large-scale survey.     

Endometrial cancer

Endometrial cancer is the most common gynaecological malignancy in the developed world. The majority of cases can be divided into two broad categories based on clinico-pathological and molecular characteristics; Type I oestrogen-dependent with endometrioid morphology and Type II non-oestrogen-dependent with serous papillary or clear cell morphology. As has been described for other malignancies, such as colorectal carcinoma, the transition from normal endometrium to carcinoma is thought to involve a stepwise accumulation of alterations in cellular regulatory pathways leading to dysfunctional cell growth. This article reviews the current knowledge of the molecular changes commonly associated with endometrial cancer and presents possible progression models.     

The histological type of endometrial cancer is not associated with menopause status at diagnosis

The latest evidence suggests that type 2 endometrial cancer may not be completely oestrogen-independent, indicating that the status of hormonal change may not be associated with the traditional classification of endometrial cancer, including the histological subtypes. However, this has not been investigated. Menopause is commonly considered a state of hormonal change in women. In the present study, we investigated the association of menopause with the histological types of endometrial cancer. Data on the histological type, menopause status at diagnosis, age at diagnosis, parity, body mass index (BMI), and overall survival rate from 2122 cases were collected. The difference in risk in developing type 1 or type 2 endometrial cancer between premenopausal and postmenopausal patients was 5.457%. A statistical difference in the association of menopause with the histological types between the two groups was seen in endometrioid and serous carcinoma, with a risk difference of 5.6 or 3.8%. A statistical difference in the association of menopause with parity between the groups was only seen in endometrioid and adenosquamous carcinoma, with a risk difference of 7.1 or 3.7%. However, BMI was not associated with histological type and the overall survival rate was not associated with menopause (P=0.764). We reported a relatively small difference in the association of menopause with type 1 or type 2, or the histological types of endometrial cancer. The survival rate was not associated with menopause. Our study suggests that menopause status at diagnosis was not strongly associated with the histological subtypes of endometrial cancer.     

子宫内膜癌发生分子机制研究进展

子宫内膜癌（Endometrial cancer,EC）是子宫内膜上皮的恶性肿瘤,可分为I型EC和II型EC。最近的分子遗传学证据表明EC是由基因表达异常改变及突变引起的,例如I型EC中常伴随着pten、k-mS、ctnnbl（β-CATENIN）、mnx、etv5／erm、hgf／met、cyr16等基因的异常;II型EC通常与p53、erbb2（her2／neu）等基因异常有关,这些异常包括基因突变、缺失、扩增、过量表达等。本文就其相关分子机制的研究进展进行综述。     

Partial silencing of fucosyltransferase 8 gene expression inhibits proliferation of Ishikawa cells,a cell line of endometrial cancer

Endometrial cancer is the most common gynecologic malignancy and is associated with increased morbidity each year, including young people. However, its mechanisms of proliferation and progression are not fully elucidated. It is well known that abnormal glycosylation is involved in oncogenesis, and fucosylation is one of the most important types of glycosylation. In particular, fucosyltransferase 8 (FUT8) is the only FUT responsible for α1, 6-linked fucosylation (core fucosylation), and it is involved in various physiological as well as pathophysiological processes, including cancer biology. Therefore, we aimed to identify the expression of FUT8 in endometrial endometrioid carcinoma and investigate the effect of the partial silencing of the FUT8 gene on the cell proliferation of Ishikawa cells, an epithelial-like endometrial cancer cell line. Quantitative real-time PCR analysis showed that FUT8 gene expression was significantly elevated in the endometrial endometrioid carcinoma, compared to the normal endometrium. The immunostaining of FUT8 and Ulex europaeus Agglutinin 1 (UEA-1), a kind of lectin family specifically binding to fucose, was detected endometrial endometrioid carcinoma. The proliferation assay showed FUT8 partial knockdown by transfection of siRNA significantly suppressed the proliferation of Ishikawa cells, concomitant with the upregulation in the gene expressions associated with the interesting pathways associated with de-ubiquitination, aspirin trigger, mesenchymal-epithelial transition (MET) et al. It was suggested that the core fucosylation brought about by FUT8 might be involved in the proliferation of endometrial endometrioid carcinoma cells.     

Differential analysis of ovarian and endometrial cancers identifies a methylator phenotype

Despite improved outcomes in the past 30 years, less than half of all women diagnosed with epithelial ovarian cancer live five years beyond their diagnosis. Although typically treated as a single disease, epithelial ovarian cancer includes several distinct histological subtypes, such as papillary serous and endometrioid carcinomas. To address whether the morphological differences seen in these carcinomas represent distinct characteristics at the molecular level we analyzed DNA methylation patterns in 11 papillary serous tumors, 9 endometrioid ovarian tumors, 4 normal fallopian tube samples and 6 normal endometrial tissues, plus 8 normal fallopian tube and 4 serous samples from TCGA. For comparison within the endometrioid subtype we added 6 primary uterine endometrioid tumors and 5 endometrioid metastases from uterus to ovary. Data was obtained from 27,578 CpG dinucleotides occurring in or near promoter regions of 14,495 genes. We identified 36 locations with significant increases or decreases in methylation in comparisons of serous tumors and normal fallopian tube samples. Moreover, unsupervised clustering techniques applied to all samples showed three major profiles comprising mostly normal samples, serous tumors, and endometrioid tumors including ovarian, uterine and metastatic origins. The clustering analysis identified 60 differentially methylated sites between the serous group and the normal group. An unrelated set of 25 serous tumors validated the reproducibility of the methylation patterns. In contrast, >1,000 genes were differentially methylated between endometrioid tumors and normal samples. This finding is consistent with a generalized regulatory disruption caused by a methylator phenotype. Through DNA methylation analyses we have identified genes with known roles in ovarian carcinoma etiology, whereas pathway analyses provided biological insight to the role of novel genes. Our finding of differences between serous and endometrioid ovarian tumors indicates that intervention strategies could be developed to specifically address subtypes of epithelial ovarian cancer.     

An approach to early genetic alterations in precancerous cells

To investigate the potential role of the PTEN tumor-suppressor gene in the carcinogenesis of ovarian endometrioid carcinoma and its related subtype, clear cell carcinoma, we examined 20 ovarian endometrioid carcinomas, 24 clear cell carcinomas and 34 solitary endometrial cysts of the ovary for LOH at 10q23.3 and point mutations of the PTEN gene, using a laser-assisted microdissection method. LOH was found in 8 of 19 ovarian endometrioid carcinomas (42.1%), 6 of 22 clear cell carcinomas (27.3%) and 13 of 23 solitary endometrial cysts (56.5%). Somatic mutations in the PTEN gene were identified in 4 of 20 ovarian endometrioid carcinomas (20.0%), 2 of 24 clear cell carcinomas (8.3%) and 7 of 34 solitary endometrial cysts (20.6%). In 5 endometrioid carcinomas with endometriosis, 3 displayed LOH events common to both the carcinoma and the endometriosis. In 7 clear cell carcinomas with endometriosis, 3 displayed LOH events common to both the carcinoma and the endometriosis. In no cases there were LOH events in the endometriosis only. These results indicate that inactivation of the PTEN gene is an early event in the development of both endometrioid and clear cell carcinoma of the ovary. A laser-assisted microdissection method enables us to collect target cells without contamination by non-tumor cells. We expect that this technique will be very useful for investigating genetic alterations in cancerous or precancerous lesions. Early genetic alterations in various precancerous cells detected by light microscopy can be readily identified by the tissue-microdissection method.     

Serum levels of VEGF and VEGF-C in patients with endometrial cancer

Endometrial cancer (EC) is the most common type of uterine cancer. A dualistic model of endometrial tumorigenesis serves as a useful way of categorizing these cancers in terms of both etiology and clinical behavior. There are two types of EC: type I and type II. Type I is so-called estrogen-dependent, and appears mostly in pre- and perimenopausal women, it is well differentiated and therefore has a better prognosis. Type II EC is estrogen-independent, diagnosed mostly in postmenopausal women, thin and fertile women, or in women with normal menstrual cycles. It is aggressive and has a worse prognosis than type I. The aim of this study was to evaluate the relationship between the pretreatment serum levels of VEGF and VEGF-C and the outcome of EC patients. A total of 98 patients treated between 1999 and 2003 were included in this study. Circulating VEGF and VEGF-C levels were determined using ELISA kits. VEGF levels among the 76 patients with type I, and the 22 patients with type II EC were significantly higher than those found in the healthy control subjects (p?相似文献   

Gene expression analysis reveals a signature of estrogen receptor activation upon loss of Pten in a mouse model of endometrial cancer

Loss of PTEN is the earliest detectable genetic lesion in the endometrioid subtype of endometrial cancer (EEC), a tumor thought to be associated with an increase in unopposed estrogen activity. Pten(+/-) mice develop endometrial neoplastic lesions with full penetrance, despite having normal estrogen levels. We have utilized oligonucleotide arrays to identify the alterations in gene expression patterns associated with loss of Pten and consequent neoplastic transformation of the endometrium. We show that 487 and 330 genes are substantially up- and downregulated, respectively, in Pten(+/-) mice. Several genes whose expression levels are impacted by loss of Pten are associated with pathways and functions that are relevant to the transformation and progression processes. Strikingly, we found that the expression levels of over 100 genes known to be regulated by estrogen receptor alpha (ERalpha) are also altered in the neoplastic uterus from Pten(+/-) mice, thus mimicking a hyperestrogenic environment. These results provide in vivo evidence supporting the hypothesis that loss of Pten and subsequent Akt activation result in the activation of several ERalpha-dependent pathways that, mimicking increased estrogen signaling, may play a pivotal role in the neoplastic process.     

Effects of tamoxifen on the endometrium and its mechanism of carcinogenicity

This study was conducted to clarify the clinicopathological characteristics of tamoxifen-associated endometrial carcinomas and its mechanisms of carcinogenesis. Seven patients with tamoxifen-associated endometrial carcinomas (TAM group) and 28 with sporadic endometrioid adenocarcinomas (EMC group) were included in the study. The clinicopathological factors, such as FIGO stage, histological type, grade, lymph node metastases, vascular invasion and the coexistence of hyperplasia, were investigated in both groups. The protein expression of p53, PTEN, hMLH1 and hMSH2 was investigated by immunohistochemistry. Microsatellite instability (MSI), k-ras and p53 mutation were also examined. In the TAM group, the histological types included five endometrioid, one endometrioid combined with serous and one clear cell type. The rates of coexistence with hyperplasia (five of seven cases) and vascular invasion (four cases) were significantly higher in the TAM group. The rates of stage III/IV (four cases) and lymph node metastasis (three cases) tended to be higher in the TAM group. Although there were no significant differences in PTEN, hMLH1 and hMSH2 expression between the two groups, p53 mutation was more frequent in three out of five cases (60%) in the TAM group compared with 2 of 15 cases in the EMC group (13.3%). No significant differences were observed concerning MSI and k-ras mutation in either group. These results suggested that TAM-associated endometrial carcinomas have overlapping biological characteristics of type I and type II endometrial carcinomas. This might explain the somewhat worse prognosis of these tumors than sporadic endometrioid carcinomas.     

The premalignant disease of the endometrium: endometrial intraepithelial neoplasia

The WHO 1994 classification for endometrial hyperplasias is based on the morphologic features of the lesions. This system characterizes the nuclear cytologic morphology as typical or atypical and describes the glandular architectural pattern as simple or complex. The main problem of this classification is the poor reproducibility. Although the predictive value of the atypical category is high, there are many typical hyperplasia cases with cancer progression. Modern molecular data related to endometrial tumorigenesis and precise computerized morphometric analysis have identified the lesion that may be considered as a precursor of endometrioid adenocarcinoma. By definition, this endometrial intraepithelial neoplasia (EIN) is a clonal proliferation of architecturally and cytologically altered endometrial glands which are prone to malignant transformation to endometrioid (type I) endometrial adenocarcinoma. The morphometric basis of EIN diagnosis is the D-score (DS), which is a logical combination of three morphometric features that represent the glandular complexity, glandular volume and cytological alterations. PTEN inactivation and K-ras mutation are the earliest genetic changes that can be revealed in these lesions. Hyperplasia cases that do not fit into the EIN categories are considered as benign or hormonal endometrial hyperplasia. This is the theoretical basis of a new classification system in premalignant endometrial diseases. Retrospective clinical data proved the high predictive value of the EIN scheme, so the decision on therapy can be more established. The reproducibility is excellent with application of precise definitions and PTEN immunohistochemistry. In the "Blue book" published in 2003 the WHO introduces the new morphometric- and molecular-based EIN system, and recommends it as an alternative classification method.     

New insights on the pathogenesis of ovarian carcinoma: molecular basis and clinical implications

Ovarian carcinoma can be subdivided into two categories termed type I and type II. Type I tumours, usually having an indolent clinical behaviour, are often detected in early stage, and rarely harbour p53 gene mutations. Each histological type has a distinct molecular profile with mutations of genes involved in different signalling transduction pathways, such as KRAS, BRAF, CTNNB1, PTEN, PIK3CA and ARID1A. Type II tumours, accounting for 75% of the cases, have a very aggressive biological behaviour, are usually in advanced stage at presentation, harbour p53 gene mutations in 80% of the cases, and sometimes have alterations of homologous recombination (HR). Both type I and type II tumours arise from extra-ovarian precursors. Serous carcinomas derive from tubal epithelium, endometrioid and clear cell carcinomas from endometrial tissue, and mucinous and Brenner tumours from transitional epithelial cells located near the tubo-peritoneal junction. These new concepts on the pathogenesis of ovarian carcinoma could deeply modify both the preventive approach in women with germ-line BRCA(1) or BRCA(2) mutations and the treatment of patients with advanced or recurrent disease. For instance, BRAF inhibitors could be used in low-grade serous carcinomas, PIK3CA inhibitors could be employed in clear cell carcinoma, and poly (ADP-ribose) polymerase inhibitors could be used not only in hereditary ovarian carcinoma but also in non-hereditary, high-grade serous ovarian carcinoma which sometimes shows defective HR.     

Identification of Optimal Reference Genes for Gene Expression Normalization in a Wide Cohort of Endometrioid Endometrial Carcinoma Tissues

Accurate normalization is a primary component of a reliable gene expression analysis based on qRT-PCR technique. While the use of one or more reference genes as internal controls is commonly accepted as the most appropriate normalization strategy, many qPCR-based published studies still contain data poorly normalized and reference genes arbitrarily chosen irrespective of the particular tissue and the specific experimental design. To date, no validated reference genes have been identified for endometrial cancer tissues. In this study, 10 normalization genes (GAPDH, B2M, ACTB, POLR2A, UBC, PPIA, HPRT1, GUSB, TBP, H3F3A) belonging to different functional and abundance classes in various tissues and used in different studies, were analyzed to determine their applicability. In total, 100 endometrioid endometrial cancer samples, which were carefully balanced according to their tumor grade, and 29 normal endometrial tissues were examined using SYBR Green Real-Time RT-PCR. The expression stability of candidate reference genes was determined and compared by means of geNorm and NormFinder softwares. Both algorithms were in agreement in identifying GAPDH, H3F3A, PPIA, and HPRT1 as the most stably expressed genes, only differing in their ranking order. Analysis performed on the expression levels of all candidate genes confirm HPRT1 and PPIA as the most stably expressed in the study groups regardless of sample type, to be used alone or better in combination. As the stable expression of HPRT1 and PPIA between normal and tumor endometrial samples fulfill the basic requirement of a reference gene to be used for normalization purposes, HPRT1 expression showed significant differences between samples from low-grade and high-grade tumors. In conclusion, our results recommend the use of PPIA as a single reference gene to be considered for improved reliability of normalization in gene expression studies involving endometrial tumor samples at different tumor degrees.     

An Integrated Approach to Uncover Driver Genes in Breast Cancer Methylation Genomes

Background

Cancer cells typically exhibit large-scale aberrant methylation of gene promoters. Some of the genes with promoter methylation alterations play “driver” roles in tumorigenesis, whereas others are only “passengers”.

Results

Based on the assumption that promoter methylation alteration of a driver gene may lead to expression alternation of a set of genes associated with cancer pathways, we developed a computational framework for integrating promoter methylation and gene expression data to identify driver methylation aberrations of cancer. Applying this approach to breast cancer data, we identified many novel cancer driver genes and found that some of the identified driver genes were subtype-specific for basal-like, luminal-A and HER2+ subtypes of breast cancer.

Conclusion

The proposed framework proved effective in identifying cancer driver genes from genome-wide gene methylation and expression data of cancer. These results may provide new molecular targets for potential targeted and selective epigenetic therapy.