Molecular assessment of depth of myometrial invasion in stage I endometrial cancer: a model based on K-ras mutation analysis

Phospho-DIGE Identified Phosphoproteins Involved in Pathways Related to Tumour Growth in Endometrial Cancer

Endometrial cancer (EC) is the most common gynecologic malignancy of the endometrium. This study focuses on EC and normal endometrium phosphoproteome to identify differentially phosphorylated proteins involved in tumorigenic signalling pathways which induce cancer growth. We obtained tissue samples from 8 types I EC at tumour stage 1 and 8 normal endometria. We analyzed the phosphoproteome by two-dimensional differential gel electrophoresis (2D-DIGE), combined with immobilized metal affinity chromatography (IMAC) and mass spectrometry for protein and phosphopeptide identification. Quantities of 34 phosphoproteins enriched by the IMAC approach were significantly different in the EC compared to the endometrium. Validation using Western blotting analysis on 13 patients with type I EC at tumour stage 1 and 13 endometria samples confirmed the altered abundance of HBB, CKB, LDHB, and HSPB1. Three EC samples were used for in-depth identification of phosphoproteins by LC-MS/MS analysis. Bioinformatic analysis revealed several tumorigenic signalling pathways. Our study highlights the involvement of the phosphoproteome in EC tumour growth. Further studies are needed to understand the role of phosphorylation in EC. Our data shed light on mechanisms that still need to be ascertained but could open the path to a new class of drugs that could hinder EC growth.

High-intermediate risk endometrial cancer: moving toward a molecularly based risk assessment profile

In the USA, endometrial cancer (EMCA) incidence is increasing as the risk factors of obesity, diabetes, and hypertension become more prevalent. Although most EMCA is detected at an early stage and surgical intervention is curative, a subset of patients termed 'high-intermediate risk' (H-IR) experience an increased rate of recurrence. Unfortunately, adjuvant therapies in patients with H-IR EMCA have yet to increase overall survival. Historically, stratification of these patients from their low-risk counterparts incorporated clinical and pathologic findings. However, due to developments in molecular testing and genomic sequencing, tumor biomarkers are now being incorporated into the risk-assessment criteria in the hope of finding molecular profile(s) that could highlight treatment regimens that will increase patient survival. Since modern research aims to accurately identify patients with a higher risk of recurrence and develop effective interventions to improve patient survival, these molecular-based analyses could allow for an enhanced understanding of a patient's true risk of recurrence to facilitate the rise of personalized medicine. This review summarizes key clinical trials and recent advances in molecular and genomic profiles that have influenced current treatment regimens for patients with H-IR EMCA and laid the foundation for subsequent research.

Early-stage endometrial cancer, CTNNB1 mutations, and the relation between lymphovascular space invasion and recurrence

INTRODUCTION

Women diagnosed with early-stage (FIGO 1) endometrial cancer, grade 1 and 2 can have a good prognosis. Most of these women can be treated successfully with a hysterectomy and bilateral salpingo-oophorectomy and without the additional adjuvant treatment that is accompanied by more risks for complications. However, when recurrence does occur, the consequences can be dire. Accurate decisions must therefore be made by surgeons to avoid either under- or over-treatment. Risk and patient stratification for tailoring treatment still need further improvement. Both histopathology and genetic variants could be integrated into the decision process if relevant factors were identified.

MATERIAL AND METHODS

Morphological features and the presence of selected genetic mutations in isolated malignant endometrial epithelial cells from these tumors were analyzed in a strictly defined cohort of FIGO 1, grade 1 and 2 low-risk endometrial cancer. Their presence in this cohort, their relation to recurrence, and the association between histopathological features and mutations were determined. This analysis was performed using archival formalin-fixed paraffin-embedded tissue, complete re-evaluation of histopathological features, laser capture microdissection of epithelial cells, and a polymerase chain reaction-based mutational screening assay.

RESULTS

Twenty-one women with recurrence, after initial identification as low-risk endometrial cancer, were compared with 20 matched control women. The histological marker of lymphovascular invasion was significantly associated with recurrence. There was also a very high prevalence of mutations in CTNNB1 gene, occurring in 50% of this cohort. PTEN mutations were also observed in 27.8% of cases and PIK3CA mutations in 22.2%; none of these mutations were significantly related to recurrence.

CONCLUSIONS

This study supports the importance of lymphovascular space invasion to identify women with significant risk for recurrence in initially low-risk, early-stage endometrial cancer. It also identifies CTNNB1 as a significant mutation in early-stage disease, and although it may not represent a marker for recurrence its high prevalence in early stage disease could have relevance for both pathogenesis and early treatment.

Epithelial to Mesenchymal Transition and Cell Biology of Molecular Regulation in Endometrial Carcinogenesis

Endometrial carcinogenesis is involved in several signaling pathways and it comprises multiple steps. The four major signaling pathways-PI3K/AKT, Ras/Raf/MEK/ERK, WNT/β-catenin, and vascular endothelial growth factor (VEGF)-are involved in tumor cell metabolism, growth, proliferation, survival, and angiogenesis. The genetic mutation and germline mitochondrial DNA mutations also impair cell proliferation, anti-apoptosis signaling, and epithelial⁻mesenchymal transition by several transcription factors, leading to endometrial carcinogenesis and distant metastasis. The PI3K/AKT pathway activates the ransforming growth factor beta (TGF-β)-mediated endothelial-to-mesenchymal transition (EMT) and it interacts with downstream signals to upregulate EMT-associated factors. Estrogen and progesterone signaling in EMT also play key roles in the prognosis of endometrial carcinogenesis. In this review article, we summarize the current clinical and basic research efforts regarding the detailed molecular regulation in endometrial carcinogenesis, especially in EMT, to provide novel targets for further anti-carcinogenesis treatment.

Racial differences in oncogene mutations detected in early-stage low-grade endometrial cancers

OBJECTIVE

To describe the pattern and frequency of oncogene mutations in white and African American women with endometrial cancer and to determine if racial differences in oncogene mutations exist among women with pathologically similar tumors.

METHODS

Patients with endometrial cancer from a large urban hospital were identified through medical records, and representative formalin-fixed paraffin-embedded tumor blocks were retrieved. The study sample included 150 patients (84 African Americans) who underwent total abdominal hysterectomy for endometrial cancer. The Sequenom MassARRAY system and the OncoCarta Assay version 1.0 (Sequenom) were used to test for 238 mutations in 19 common oncogenes. The χ(2) test and the Fisher exact test were used to assess differences in distribution of variables by race and oncogene mutation status.

RESULTS

There were 20 mutations identified in 2 oncogenes (PIK3CA and KRAS) in tumors from 19 women (12.7%). Most of the mutations were found in PIK3CA (16/20). Thirteen percent of endometrioid tumors harbored mutations (11 PIK3CA and 2 KRAS) as did 29% of the malignant mixed Mullerian tumors (3 PIK3CA and 1 KRAS). There were no observed mutations in serous, clear cell, or mucinous tumor types. Among low-grade endometrioid cancers, tumors from African American patients were significantly associated with harboring either a KRAS or PIK3CA mutation (P = 0.04), with 7 PIK3CA mutations and all 4 KRAS mutations identified in African American women.

CONCLUSIONS

This study provides preliminary evidence that oncogene mutation frequency of some subtypes of histologically similar endometrial carcinoma differ by race. Additional studies are needed to further explore this phenomenon in patients with endometrial carcinoma.

Emerging issues of the expression profiling technologies for the study of gynecologic cancer

Evaluation of the prognostic parameters of gynecologic cancer has shown their failure for classification according to the clinical behavior or the prediction of its outcome. This weakness has important implications on prognosis and treatment. The increasing understanding of the complexity of the human genome, coupled with the development of high throughput analysis techniques and bioinformatics tools, has changed our concepts on cancer biology, by shifting our targets to a global analysis of the transcriptome and the proteome, linking genes and their products into functional pathways. These approaches permit the documentation of expression patterns of thousands of genes within a cell. With the use of DNA microarray technology, it is feasible to identify signature patterns of expression in tumor samples that faithfully correlate with its biology, providing accurate prognosis for each cancer patient and thus a rational customized treatment. At this stage, there is a need for systematic studies for the validation of these novel approaches. In this review, we provide a basic background of the concept of the technology, highlight several emerging issues from their applications on gynecologic cancer, discuss a series of important themes and problems regarding their interpretation and relevance for the clinicians, and comment on future areas of research.

K-ras as a target for cancer therapy

The central role K-, H- and N-Ras play in regulating diverse cellular pathways important for cell growth, differentiation and survival is well established. Dysregulation of Ras proteins by activating mutations, overexpression or upstream activation is common in human tumors. Of the Ras proteins, K-ras is the most frequently mutated and is therefore an attractive target for cancer therapy. The complexity of K-ras signaling presents many opportunities for therapeutic targeting. A number of different approaches aimed at abrogating K-ras activity have been explored in clinical trials. Several of the therapeutic agents tested have demonstrated clinical activity, supporting ongoing development of K-ras targeted therapies. However, many of the agents currently being evaluated have multiple targets and their antitumor effects may not be due to K-Ras inhibition. To date, no selective, specific inhibitor of K-ras is available for routine clinical use. In this review, we will summarize the structure and function of K-ras with attention to its role in tumorigenesis and discuss the successes and failures of the various strategies designed to therapeutically target this important oncogene.