Chromosomal abnormalities and microsatellite instability in sporadic endometrial cancer

Genetic Instability Markers in Cancer

High frequency of mutations seems to determine a higher occurrence of neoepitope formation and, thus, tumor immunogenicity. A somatic hypermutated status could thus act as a predictive biomarker of responsiveness to immunotherapy with recent immune checkpoint inhibitors. Among several factors involved in determining the hypermutated status, such as inactivating mutations in the DNA polymerases as well as exposure to external (cigarette smoke, UV radiation, chemicals) and endogenous (reactive oxygen species) mutagens, a defective DNA mismatch repair system may give rise to genetic instability and, particularly, to microsatellite instability (MSI). The occurrence of MSI has been associated with increased load of mutations and expression of abundant peptides that serve as neoantigens to elicit an immune response within a context of a favorable tumor microenvironment. Here we describe methodological strategies to investigate for the presence of the MSI phenotype in cancer samples, through a combination of molecular approaches performed on paraffin-embedded tissues.

Prognostic implications of mismatch repair deficiency in patients with nonmetastatic colorectal and endometrial cancer

Background

The clinical relevance of mismatch repair (MMR) status in patients with nonmetastatic cancer across tumour types remains unclear. Our goal was to investigate the prognostic role of MMR deficiency in patients with stage I-III colorectal and endometrial cancer.

Methods

Patients with nonmetastatic colorectal and endometrial cancer with tumour tissue available for analysis were identified through the Hellenic Cooperative Oncology Group (HeCOG)'s tumour repository. Patients had been referred to Departments of Medical Oncology affiliated with HeCOG. MMR protein expression was evaluated by immunohistochemistry. The primary outcome measure was overall survival (OS).

Results

From May 1990 to September 2012, 1158 patients with nonmetastatic colorectal (N = 991) and endometrial cancer (N = 167) were identified (median age: 64 years, men: 544). All patients with colorectal and 109 (65%) with endometrial cancer had received adjuvant treatment. MMR deficiency was observed in 114 (11.5%) of colorectal and 80 (47.9%) of endometrial tumours. More commonly deficient proteins were PMS2 (69 patients, 7%) and MLH1 (63 patients, 6.5%) in colorectal cancer and MSH2 (58 patients, 34.7%) in endometrial cancer. Colorectal MMR-deficient (dMMR) tumours were more likely to be right sided (65 % dMMR vs 27 % proficient MMR, pMMR; p < 0.001), high grade (31% vs 15%, χ², p < 0.001) and with a mucinous component (64% vs 42%, p < 0.001). Endometrial dMMR tumours were more often of endometrioid histology (51.4 % endometrioid vs 20 % serous/clear cell, p = 0.020). Compared with MMR proficiency, MMR deficiency was associated with improved OS in patients with endometrial cancer (HR = 0.38, 95% CI 0.20 to 0.76, p = 0.006), but not in patients with colorectal cancer (HR = 0.73, 95% CI 0.49 to 1.09, p = 0.130). After adjusting for age, stage and grade, MMR deficiency maintained its favourable prognostic significance in patients with endometrial cancer (HR = 0.42, 95% CI 0.20 to 0.88, p = 0.021).

Conclusions

DMMR was associated with improved outcomes in patients with nonmetastatic endometrial cancer, but not in patients with nonmetastatic colorectal cancer who received adjuvant chemotherapy.

Genetic alterations in main candidate genes during melanoma progression

Cutaneous melanoma is a common and aggressive human skin cancers. Much is actually known about the molecular mechanisms underlying melanoma pathogenesis. The aim of the study was to evaluate any possible correlation between mutations in main growth-controlling genes (BRAF, NRAS, CDKN2A) and copy number variations in frequently amplified candidate genes (MITF, EGFR, CCND1, cMET, and cKIT) during melanoma initiation and progression. A large series of primary and secondary melanoma tissue samples (N = 274) from 232 consecutively-collected patients of Italian origin as well as 32 tumor cell lines derived from primary and metastatic melanomas underwent mutation screening and fluorescence in situ hybridization (FISH) analysis. Overall, BRAF, NRAS, and CDKN2A were found mutated in 62.5%, 12.5% and 59% cell lines and in 47%, 16%, 12% tumor tissues, respectively. Quite identical mutation patterns between primary tumors and metastatic lesions were found for BRAF and NRAS genes; mutations of CDKN2A gene appeared to be instead selected during tumor progression. In cell lines, high rates of gene amplifications were observed (varying from 12.5% for cKIT to 50% for MITF); vast majority of cell lines (75%) presented at least one amplified gene. Conversely, prevalence of gene amplification was significantly and progressively decreasing in melanoma metastases (12%) and primary melanomas (4%). Our findings suggest that gene amplifications may be acquired during the late phases of melanoma evolution and mostly act as "passenger" or "non-causative" alterations.

The Role of Chromosomal Instability in Cancer and Therapeutic Responses

Cancer is one of the leading causes of death, and despite increased research in recent years, control of advanced-stage disease and optimal therapeutic responses remain elusive. Recent technological improvements have increased our understanding of human cancer as a heterogeneous disease. For instance, four hallmarks of cancer have recently been included, which in addition to being involved in cancer development, could be involved in therapeutic responses and resistance. One of these hallmarks is chromosome instability (CIN), a source of genetic variation in either altered chromosome number or structure. CIN has become a hot topic in recent years, not only for its implications in cancer diagnostics and prognostics, but also for its role in therapeutic responses. Chromosomal alterations are mainly used to determine genetic heterogeneity in tumors, but CIN could also reveal treatment efficacy, as many therapies are based on increasing CIN, which causes aberrant cells to undergo apoptosis. However, it should be noted that contradictory findings on the implications of CIN for the therapeutic response have been reported, with some studies associating high CIN with a better therapeutic response and others associating it with therapeutic resistance. Considering these observations, it is necessary to increase our understanding of the role CIN plays not only in tumor development, but also in therapeutic responses. This review focuses on recent studies that suggest possible mechanisms and consequences of CIN in different disease types, with a primary focus on cancer outcomes and therapeutic responses.

Intratumoral CD8+ Lymphocyte Infiltration as a Prognostic Factor and Its Relationship With Cyclooxygenase 2 Expression and Microsatellite Instability in Endometrial Cancer

OBJECTIVE

Microsatellite instability (MSI) is caused by a defective DNA mismatch repair system. Colorectal cancer in MSI-positive patients is characterized by an increased number of tumor-infiltrating lymphocytes. On the other hand, it has recently been reported that cyclooxygenase 2 (COX-2) suppresses antitumor immunity. The objectives of the present study were to clarify the relationships among MSI status, COX-2 expression, and antitumor immune status and to verify impact of these factors on the prognosis of endometrial cancer.

METHODS

The data of 123 patients with endometrial cancer were analyzed. The numbers of tumor-infiltrating CD8 T lymphocytes within cancer cell nests (TILs), as a representative of the antitumor immunity, and COX-2 expression levels in the tumor cells were analyzed by immunohistochemical staining. Microsatellite instability was evaluated by polymerase chain reaction analysis for 11 markers. Fisher exact probability test, Kaplan-Meier method, and proportional hazards analysis were used for the statistical analyses.

RESULTS

The MSI-positive tumors showed significantly higher grades (G2 or G3) and significantly larger numbers of TILs than did the MSI-negative tumors. The COX-2-high group showed significantly fewer TILs than did the COX-2-low group. Multivariate analysis identified a low number of TILs (<10), positive lymph node involvement, and high tumor malignancy grade as factors independently associated with poor prognosis. The prognosis was significantly poorer in the patients with MSI-positive tumors with high COX-2 expression than in those with MSI-positive tumors showing low COX-2 expression.

CONCLUSIONS

The number of TILs, which was increased by MSI and decreased by COX-2 expression, was associated with a poorer prognosis in patients with endometrial cancer. We also propose that COX-2 may block MSI-activated TILs in the tumor microenvironment.

Clinicopathologic Significance of Mismatch Repair Defects in Endometrial Cancer: An NRG Oncology/Gynecologic Oncology Group Study

PURPOSE

The clinicopathologic significance of mismatch repair (MMR) defects in endometrioid endometrial cancer (EEC) has not been definitively established. We undertook tumor typing to classify MMR defects to determine if MMR status is prognostic or predictive.

METHODS

Primary EECs from NRG/GOG0210 patients were assessed for microsatellite instability (MSI), MLH1 methylation, and MMR protein expression. Each tumor was assigned to one of four MMR classes: normal, epigenetic defect, probable mutation (MMR defect not attributable to MLH1 methylation), or MSI-low. The relationships between MMR classes and clinicopathologic variables were assessed using contingency table tests and Cox proportional hazard models.

RESULTS

A total of 1,024 tumors were assigned to MMR classes. Epigenetic and probable mutations in MMR were significantly associated with higher grade and more frequent lymphovascular space invasion. Epigenetic defects were more common in patients with higher International Federation of Gynecology and Obstetrics stage. Overall, there were no differences in outcomes. Progression-free survival was, however, worse for women whose tumors had epigenetic MMR defects compared with the MMR normal group (hazard ratio, 1.37; P < .05; 95% CI, 1.00 to 1.86). An exploratory analysis of interaction between MMR status and adjuvant therapy showed a trend toward improved progression-free survival for probable MMR mutation cases.

CONCLUSION

MMR defects in EECs are associated with a number of well-established poor prognostic indicators. Women with tumors that had MMR defects were likely to have higher-grade cancers and more frequent lymphovascular space invasion. Surprisingly, outcomes in these patients were similar to patients with MMR normal tumors, suggesting that MMR defects may counteract the effects of negative prognostic factors. Altered immune surveillance of MMR-deficient tumors, and other host/tumor interactions, is likely to determine outcomes for patients with MMR-deficient tumors.

The Significance of Mismatch Repair Deficiency in Young Patients With Endometrial Cancer

The objective of this study was to identify the tumor characteristics associated with mismatch repair deficiency in young patients with endometrial carcinoma. Young patients (45 yr old or younger) with endometrial carcinoma treated by hysterectomy in our institution between July 2001 and June 2009 were identified. The clinical and pathologic data were obtained by review of clinical records. Among the 122 cases identified, paraffin sections were available in 67 cases for immunohistochemical staining and frozen tissue available in 62 cases for microsatellite instability (MSI) analysis. Both paraffin sections and frozen tissue were available in 36 cases. Among the 67 cases with immunohistochemical staining, 22 (32.8%) showed loss of expression of at least 1 mismatch repair protein. Defective MLH1 or MSH2 expression was associated with poor prognostic factors, including a higher incidence of pelvic lymph nodes metastasis (P=0.018) and higher stage (P=0.022) for MLH1, and an increased risk of lymphovascular permeation (P=0.015) for MSH2. On the contrary, defective MSH6 protein expression was associated with a lower incidence of high-grade tumors (P=0.04). Among the 62 cases with MSI analysis, 12 (19.4%) tumors were classified as microsatellite-high (MSI-H), whereas 2 (3.2%) were classified as microsatellite-low (MSI-L). There was no difference in the pathologic characteristics between MSI-stable and MSI-H tumor. We concluded that defective mismatch repair expression is important in young patients with endometrial carcinoma, with MSH6 protein being most commonly affected. The phenotype resulting from defective MSH6 expression was different from that caused by MLH1 or MSH2 loss.

Molecular analysis of isolated tumor glands from endometrial endometrioid adenocarcinomas

We studied the extensive molecular alterations of endometrial endometrioid adenocarcinoma (EEA) using a crypt isolation method. We analyzed copy number variation (CNV) using a single nucleotide polymorphism (SNP) array, genetic mutations (KRAS, BRAF, p53, PIK3CA), DNA methylation and microsatellite instability (MSI) status. In addition, loss of PTEN protein expression was examined. Increased chromosome copy numbers of 1q21.2-44 (22%) and 10q11.21-23.31 (28%) were seen relatively frequently in EEA, and copy-neutral loss of heterozygosity (LOH) was also observed in 10q22.1-26.3 (22%). The CNV patterns of EEA were classified into four groups through hierarchical cluster analysis. Cluster 1 had many CNVs of 10q, and cluster 2 was characterized by MSI status. In cluster 3, increased CNVs of 1q were often seen. In cluster 4, p53 mutations were detected. KRAS and PIK3CA mutations and reduced PTEN protein expression were common to all groups. On the other hand, CpG island methylator phenotype (CIMP) was rare in all groups. The data indicated an association with chromosomal gain of 1q and 10q or 10q copy-neutral LOH in some cases. We suggest that EEA consists of four groups that are characterized with molecular alterations.

The detection and implication of genome instability in cancer

Genomic instability is a hallmark of cancer that leads to an increase in genetic alterations, thus enabling the acquisition of additional capabilities required for tumorigenesis and progression. Substantial heterogeneity in the amount and type of instability (nucleotide, microsatellite, or chromosomal) exists both within and between cancer types, with epithelial tumors typically displaying a greater degree of instability than hematological cancers. While high-throughput sequencing studies offer a comprehensive record of the genetic alterations within a tumor, detecting the rate of instability or cell-to-cell viability using this and most other available methods remains a challenge. Here, we discuss the different levels of genomic instability occurring in human cancers and touch on the current methods and limitations of detecting instability. We have applied one such approach to the surveying of public tumor data to provide a cursory view of genome instability across numerous tumor types.

Clinical value of DNA content assessment in endometrial cancer

Endometrial carcinoma (EC) is the most common gynecologic cancer in industrialized countries. Traditional prognostic markers include FIGO stage, histologic subtype, and histologic grade. DNA ploidy was introduced as a prognostic marker 30 years ago, and the majority of published literature demonstrates significant associations between tumor aneuploidy and poorer prognosis in EC. However, ploidy analysis is not routinely implemented in the clinic. We reviewed the literature on clinical value of ploidy measured by DNA content as a prognostic marker, and its potential role as a predictive marker in EC.  PubMed was searched for papers evaluating the prognostic or predictive role of ploidy in EC. Search criteria were "DNA ploidy prognosis/predictive value endometrial cancer/carcinoma". Only articles written in English, published year 2000 or later were included.  The majority of the studies demonstrated highly significant correlation between DNA index (DI) and survival, in univariate analysis including stages I-IV, and in subgroup analysis of stage I and stage I-II EC. Several studies also showed significant association between DI and survival in multivariate analysis. Few studies have evaluated DI as a prognostic marker in a prospective setting. No studies evaluating DI as a predictive marker in EC were identified. In other cancer types, ploidy has been linked to prediction of response to hormonal therapy and chemotherapy.  Ploidy assessment in EC by DI is a strong prognostic marker. Still, its clinical applicability needs validation in a routine diagnostic, prospective setting with sufficient number of patients, characterized by state of the art histopathological evaluation and surgical staging.

Protein profiling of genomic instability in endometrial cancer

DNA aneuploidy has been identified as a prognostic factor in the majority of epithelial malignancies. We aimed at identifying ploidy-associated protein expression in endometrial cancer of different prognostic subgroups. Comparison of gel electrophoresis-based protein expression patterns between normal endometrium (n = 5), diploid (n = 7), and aneuploid (n = 7) endometrial carcinoma detected 121 ploidy-associated protein forms, 42 differentially expressed between normal endometrium and diploid endometrioid carcinomas, 37 between diploid and aneuploid endometrioid carcinomas, and 41 between diploid endometrioid and aneuploid uterine papillary serous cancer. Proteins were identified by mass spectrometry and evaluated by Ingenuity Pathway Analysis. Targets were confirmed by liquid chromatography/mass spectrometry. Mass spectrometry identified 41 distinct polypeptides and pathway analysis resulted in high-ranked networks with vimentin and Nf-κB as central nodes. These results identify ploidy-associated protein expression differences that overrule histopathology-associated expression differences and emphasize particular protein networks in genomic stability of endometrial cancer.

Genomic instability influences the transcriptome and proteome in endometrial cancer subtypes

BACKGROUND

In addition to clinical characteristics, DNA aneuploidy has been identified as a prognostic factor in epithelial malignancies in general and in endometrial cancers in particular. We mapped ploidy-associated chromosomal aberrations and identified corresponding gene and protein expression changes in endometrial cancers of different prognostic subgroups.

METHODS

DNA image cytometry classified 25 endometrioid cancers to be either diploid (n = 16) or aneuploid (n = 9), and all uterine papillary serous cancers (UPSC) to be aneuploid (n = 8). All samples were subjected to comparative genomic hybridization and gene expression profiling. Identified genes were subjected to Ingenuity pathway analysis (IPA) and were correlated to protein expression changes.

RESULTS

Comparative genomic hybridization revealed ploidy-associated specific, recurrent genomic imbalances. Gene expression analysis identified 54 genes between diploid and aneuploid endometrioid carcinomas, 39 genes between aneuploid endometrioid cancer and UPSC, and 76 genes between diploid endometrioid and aneuploid UPSC to be differentially expressed. Protein profiling identified AKR7A2 and ANXA2 to show translational alterations consistent with the transcriptional changes. The majority of differentially expressed genes and proteins belonged to identical molecular functions, foremost Cancer, Cell Death, and Cellular Assembly and Organization.

CONCLUSIONS

We conclude that the grade of genomic instability rather than the histopathological subtype correlates with specific gene and protein expression changes. The identified genes and proteins might be useful as molecular targets for improved diagnostic and therapeutic intervention and merit prospective validation.

Biomarkers and microsatellite instability analysis of curettings can predict the behavior of FIGO stage I endometrial endometrioid adenocarcinoma

The prognostic value of molecular biomarkers, microsatellite instability, DNA ploidy and morphometric mean shortest nuclear axis in endometrial cancer is conflicting, possibly due to the fact that different studies have used mixtures of histotypes, FIGO stages and different non-standardized non-automated methods. We have evaluated the prognostic value of classical prognostic factors, molecular biomarkers, microsatellite instability, DNA ploidy and morphometric mean shortest nuclear axis in a population-based cohort of FIGO stage I endometrial endometrioid adenocarcinomas. Curettings of 224 FIGO stage I endometrial endometrioid adenocarcinoma patients were reviewed. Clinical information, including follow-up, was obtained from the patients' charts. Microsatellite instability and morphometric mean shortest nuclear axis were obtained in whole tissue sections and molecular biomarkers using tissue microarrays. DNA ploidy was analyzed by image cytometry. Univariate (Kaplan-Meier method) and multivariate (Cox model) survival analysis was performed. With median follow-up of 66 months (1-209), 14 (6%) patients developed metastases. Age, microsatellite instability, molecular biomarkers (p16, p21, p27, p53 and survivin) and morphometric mean shortest nuclear axis had prognostic value. With multivariate analysis, combined survivin, p21 and microsatellite instability overshadowed all other variables. Patients in which any of these features had favorable values had an excellent prognosis, in contrast to those with either high survivin or low p21 (97 vs 78% survival, P<0.0001, hazard ratio=7.8). Combined high survivin and low p21 values and microsatellite instability high identified a small subgroup with an especially poor prognosis (survival rate 57%, P=0.01, hazard ratio=5.6). We conclude that low p21 and high survivin expression are poor prognosis indicators in FIGO stage I endometrial endometrioid adenocarcinoma, especially when high microsatellite instability occurs.

High frequency microsatellite instability has a prognostic value in endometrial endometrioid adenocarcinoma, but only in FIGO stage 1 cases

OBJECTIVES

To analyze the prognostic value of microsatellite instability (MSI) in a population-based study of FIGO stage 1-4 endometrial endometrioid adenocarcinomas.

STUDY DESIGN

Survival analysis in 273 patients of MSI status and clinico-pathologic features. Using a highly sensitive pentaplex polymerase chain reaction to establish MSI status, cases were divided into microsatellite stable (MSS), MSI-low (MSI-L, 1 marker positive) and MSI-high (MSI-H, 2-5 markers positive).

RESULTS

After 61 months median follow-up (1-209), 34 (12.5%) of the patients developed metastases but only 6.4% of the FIGO-1. MSI (especially as MSI-H versus MSS/MSI-Lcombined) was prognostic in FIGO-1 but not in FIGO2-4. The 5 and 10 year recurrence-free survival rates were 98% and 95% in the MSS/MSI-L versus 85% and 73% in the MSI-H patients (P = 0.005).

CONCLUSIONS

MSI-H status assessed by pentaplex polymerase chain reaction is an indicator of poor prognosis in FIGO 1, but not in FIGO 2-4 endometrial endometrioid adenocarcinomas.

DNA methylation in endometrial cancer

Endometrial cancer is the most commonly diagnosed gynecological cancer, and it has been shown to be a complex disease driven by abnormal genetic, and epigenetic alterations, as well as environmental factors. Epigenetic changes resulting in aberrant gene expression are dynamic and modifiable features of many cancer types. A significant epigenetic change is aberrant DNA methylation. In this review, we review evidence on the role of aberrant DNA methylation, examining changes in relation to endometrial carcinogenesis, and report on recent advances in the understanding of the contribution of aberrant DNA methylation to endometrial cancer with the emphasis on the role of dietary/ lifestyle and environmental factors, as well as opportunities and challenges of DNA methylation in endometrial cancer management and prevention.

Prognostic value of microsatellite instability (MSI) and PTEN expression in women with endometrial cancer: results from studies of the NCIC Clinical Trials Group (NCIC CTG)

AIM

The impact of PTEN status and microsatellite instability (MSI) on the prognosis of women with endometrial cancer is controversial. The aim of this study was to investigate MSI and PTEN expression in two patient populations using data from NCIC CTG studies.

METHODS

Archival paraffin embedded tumour from women with endometrial cancer enrolled in NCIC CTG studies: EN5 (stage I/II) and IND 126, 148 and 160 (advanced/recurrent disease) were examined for MSI using BAT25/26 and for PTEN expression using immunohistochemistry. PTEN and MSI status were correlated with clinicopathologic variables and survival using data from NCIC CTG trial databases.

RESULTS

PTEN and MSI results were available from 128 and 163 patients, respectively. MSI+ tumours were more common in women enrolled in EN5 compared to the IND studies (p=0.01). PTEN negative tumours were associated with improved survival in both univariate (hazard ratio (HR) 0.55, 95% confidence interval (CI) 0.32-0.94; p=0.03) and multivariate (adjusted HR 0.54, 95% CI 0.30-0.96; p=0.03) analyses in women enrolled in IND studies. Microsatellite stable tumours were associated with an improved prognosis in univariate (HR 0.18, 95% CI 0.06-0.51; p<0.0001) and multivariate (adjusted HR 0.16, 95% CI 0.05-0.5; p<0.0001) analyses in women enrolled in EN5. There was no significant correlation between MSI and PTEN status.

CONCLUSIONS

PTEN negative tumours in women with advanced disease are associated with improved survival. MSI+ tumours are more common in early stage disease and in this group of women are associated with a worse prognosis.

DNA mismatch repair deficiency in endometrial carcinoma

Microsatellite instability (MSI) is the hallmark of a molecular pathway to carcinogenesis due to sporadic or inherited abnormalities of DNA mismatch repair genes. Inherited mutations are seen in hereditary nonpolyposis colorectal cancer syndrome. Endometrial carcinoma shows as high an incidence of MSI as does colorectal carcinoma. This review provides a framework for the gynecologic pathologist to understand the complexities of MSI in endometrial carcinoma, by discussing the basic mechanisms of mismatch repair and carcinogenesis, testing, the morphologic features of MSI endometrial cancer and the contradictory data regarding prognosis.

Molecular alterations at chromosome 9p21 in melanocytic naevi and melanoma

BACKGROUND

The chromosome 9p21 and its CDKN locus, with the p16 tumour suppressor gene (CDKN2A), are recognized as the genomic regions involved in the pathogenesis of melanoma.

OBJECTIVES

To elucidate further the role of such regions during the different phases of melanocytic tumorigenesis.

METHODS

Tissue sections from naevi, primary and metastatic melanomas were investigated by fluorescence in situ hybridization for allelic loss at the 9p21 chromosome and by immunochemistry for p16CDKN2A expression.

RESULTS

Dysplastic naevi and primary or secondary melanomas were found to carry hemizygous deletions within the entire 9p21 region at similar frequencies (varying from 55% to 62%). Allelic deletion spanning the CDKN locus was observed at significantly increased rates moving from early (7%) to advanced (28%) primary melanomas and to secondary melanoma lesions (37%) (P=0.018). Also, inactivation of the p16 gene (CDKN2A) was absent in naevi and present at steadily increasing rates moving from primary melanomas (7% early lesions to 17% advanced lesions) to melanoma metastases (62%) (P=0.004).

CONCLUSIONS

Our findings indicate that, in a model of sequential accumulation of genetic alterations, 9p21 deletions may play a role in melanocytic transformation and tumour initiation whereas rearrangements at the CDKN locus, and p16 gene (CDKN2A) inactivation may contribute to tumour progression.

Microsatellite Instability and Epigenetic Inactivation of MLH1 and Outcome of Patients With Endometrial Carcinomas of the Endometrioid Type

Purpose

Most studies of microsatellite instability (MSI) and outcomes in endometrial cancer patients have included varied histologic subtypes. Nonetheless, MSI occurs almost exclusively in endometrioid tumors. The impact of MSI on outcomes in patients with endometrial cancer is controversial. We sought to determine whether MSI and MLH1 methylation are associated with clinicopathologic variables and survival outcomes in a large series of patients with endometrial carcinomas of the endometrioid type.

Patients and Methods

Tumor samples, blood, and clinicopathologic data were prospectively collected and analyzed for 446 patients with endometrioid carcinomas. MSI was determined using five National Cancer Institute (NCI) consensus panel markers, and the methylation status of the MLH1 promoter was determined by combined bisulfite restriction analysis (COBRA). Associations with clinicopathologic variables and survival outcomes were evaluated.

Results

MSI was identified in 147 cases (33%). MSI was associated with higher International Federation of Gynecology and Obstetrics (FIGO) grade (P < .0001). MSI+ tumors without MLH1 methylation were associated with younger age (P < .001). MSI was not associated with overall survival (OS; hazard ratio [HR], 1.011; 95% CI, 0.688 to 1.484; P = .96) or disease-free survival (DFS; HR 0.951; 95% CI, 0.554 to 1.635; P = .86). The combined MSI/MLH1 methylation status (treating MSI− as the reference) did not predict OS (MSI+/MLH1-U: HR, 0.62; 95% CI, 0.27 to 1.44; P = .26; MSI+/MLH1-M: HR, 0.95; 95% CI, 0.62 to 1.46; P = .82) or DFS (MSI+/MLH1-U: HR, 0.51; 95% CI, 0.22 to 1.19; P = .12; MSI+/MLH1-M: HR, 0.93; 95% CI, 0.62 to 1.40; P = .72).

Conclusion

MSI is not associated with survival in patients with endometrioid endometrial cancer.

Molecular genetic defects in endometrial carcinomas: microsatellite instability, PTEN and beta-catenin (CTNNB1) genes mutations

PURPOSE

The present study aims to assess the incidence of microsatellite instability (MSI) and mutations in the PTEN and beta-catenin (CTNNB1) genes in endometrial carcinomas and to analyze the detected defects in these factors in relation to each other and to the clinico-pathological features of tumors.

MATERIALS AND METHODS

In a series of 56 endometrioid endometrial carcinomas, the status of MSI was determined using nine polymorphic markers, and mutations in all exons of the PTEN gene and in exon 3 of the CTNNB1 gene were evaluated by SSCP and sequencing methods.

RESULTS

Microsatellite instability was found in 18 carcinomas (32.1%, MSI+); the remaining 38 tumors were microsatellite stable (MSI-). In 15 cases (26.8%), a loss of heterozygosity (LOH) at the studied microsatellite markers also occurred. In 29 carcinomas (51.8%), mutations were found in the PTEN gene and in nine tumors (16.1%) in the CTNNB1 gene. PTEN mutations occurred significantly more frequently in MSI+ than in MSI- tumors (77.8 vs. 39.5%, p = 0.007), but, except for one, none of them was attributable to MSI. In contrast, incidence of CTNNB1 mutations in MSI+ and MSI- tumors no significantly differed between themselves (16.7 vs. 15.8%, p = 0.760). Interestingly, mutations in the CTNNB1 gene most frequently coexisted with mutations in the PTEN gene (7/9, 77.8%). However, this finding requires future verification on a larger group of cases. The incidence of MSI and PTEN, but not CTNNB1 mutations, was significantly more common in poorly, than in well-to-moderately, differentiated tumors (G3 vs. G1 + G2; p = 0.042, 0.039 and 0.958, respectively).

CONCLUSION

We conclude that most frequently occurring mutations in the PTEN gene may be a key event for the tumorigenesis of endometrioid endometrial carcinomas, while coexistence or absence of microsatellite instability or mutations in the CTNNB1 gene may reflect the heterogeneity of molecular mechanisms contributing to the development of these tumors.

Microsatellite instability in mitochondrial genome of common female cancers

To investigate the occurrence of mitochondrial genome instability in primary cervical, endometrial, ovarian, and breast carcinomas, we analyzed 12 microsatellite regions in mitochondrial DNA (mtDNA) of tumor tissues and their matched normal controls. Four of the 12 microsatellite markers starting at nucleotide position (np) 303, 514, 956, and 16184, respectively, exhibited instability as indicated by the change in length of short base-repetitive sequences of mtDNA in cancer tissue relative to that in control normal tissue from the same patient. About 25.4% of cervical cancers, 48.4% of endometrial cancers, 21.9% of ovarian cancers, and 29.4% of breast cancers carried one or more mitochondrial microsatellite instability (mtMSI). mtMSI was frequently detected in the D-loop region but rarely occurred in the coding region. A relatively long C tract interrupted by a T residue is the mtMSI hot spot in all four types of cancer studied. Different tumors have different mtMSI profiles. In particular, the frequency of mtMSI in endometrial cancer was significantly higher than in the other three types of cancer. Furthermore, carriers of a germ-line T to C polymorphism at np 16189 could be more susceptible to breast cancer development in light of the higher frequency detected in cancer patients than in normal individuals.

Microsatellite instability in endometrioid endometrial carcinoma: correlation with clinically relevant pathologic variables

This study of 218 patients with endometrioid endometrial carcinoma explores the relationship between microsatellite instability (MSI) as established by the BAT26 method and the common pathologic variables of prognostic and therapeutic significance. MSI was positively correlated with grade, associated endometrial atrophy, squamous metaplasia, isthmic involvement, depth of myoinvasion, vascular invasion-associated changes, extrauterine tumor spread, and extramyometrial angiolymphatic spread. There was no significant correlation with carcinoma developing in adenomyosis, mucinous metaplasia, tumor size, cornual involvement, cervical extension, uterine serosal involvement, and targeted lymphoid response. The positive correlations are discussed in terms of molecular genetics.

Clinicopathologic Significance of Defective DNA Mismatch Repair in Endometrial Carcinoma

Purpose

Defective DNA mismatch repair is commonly present in sporadic manifestations of gastrointestinal, endometrial, and other cancers. The pathognomonic molecular manifestation of this repair defect is microsatellite instability (MSI). Here, we test the hypothesis that MSI predicts the clinicopathologic features of endometrial carcinoma.

Patients and Methods

A retrospective cohort of 473 patients treated for endometrial carcinoma at this institution was identified. All cases were reviewed by a gynecologic pathologist, and clinical information was abstracted from medical records. Using consensus criteria, DNA samples from nontumor and tumor tissue pairs were genotyped for MSI. Associations between MSI status and pathologic and clinical variables were assessed.

Results

Ninety-three (20%) of 473 tumors were MSI+. In the MSI+ tumor group compared with the MSI− tumor group, the proportion of advanced compared with early-stage tumors was higher (92% v 81%; P = .01), as was the proportion of tumors of endometrioid compared with nonendometrioid histologic subtype (94% v 23%; P = .001), and the proportion of tumors with myometrial invasion compared with those with none (92% v 78%; P = .01). By multivariate analyses, disease-free survival (hazard ratio, 0.3; 95% CI, 0.2 to 0.7) and disease-specific survival (hazard ratio, 0.3; 95% CI, 0.1 to 0.8) were significantly improved in patients with MSI+ tumors.

Conclusion

In endometrial carcinoma, the presence of MSI was independently associated with a more favorable clinical outcome.

Transposable elements – Is there a link between evolution and cancer?

Currently, the most predominant theory concerning the formation of cancer is that it is a genetic accident. Accordingly, various agents are thought to cause DNA damage which then subsequently activates oncogenes and inactivates tumor suppressor genes. This article, however, describes a theory that interprets cancer as a misguided adaptation. Stressors, which cannot be compensated for with the usual cell possibilities might arouse evolutionary mechanisms intended to create new protein variants. One of these is the activation of transposable elements which leads to a reformatting of the genome. The result of this process is either a cell that survives very well under stress (and will, therefore, never be detected), a dead cell (in case the process is ineffective), or a more or less abnormal and harmful cell that builds up a new but cancerous organ. This theory explains the complex genetic alterations which are present in almost all cancer cells. It also explains the action of non-mutagenic carcinogens. As part of the reformatting process of the cancer cell genome, activation of oncogenes and inactivation of tumor suppressor genes are not stochastic events but the result of an unlucky genomic composition.

Detection of chromosomal aberrations by fluorescence in situ hybridization in cervicovaginal biopsies from women exposed to diethylstilbestrol in utero

Epidemiologic studies have associated estrogens with human neoplasms such as those in the endometrium, cervix, vagina, breast, and liver. Perinatal exposure to natural (17beta-estradiol [17beta-E(2)]) and synthetic (diethylstilbestrol [DES]) estrogens induces neoplastic changes in humans and rodents. Previous studies demonstrated that neonatal 17beta-E(2) treatment of mice results in increased nuclear DNA content of cervicovaginal epithelium that precedes histologically evident neoplasia. In order to determine whether this effect was associated with chromosomal changes in humans, the frequencies of trisomy of chromosomes 1, 7, 11, and 17 were evaluated by the fluorescence in situ hybridization (FISH) technique in cervicovaginal tissue from 19 DES-exposed and 19 control women. The trisomic frequencies were significantly elevated in 4 of the 19 (21%) DES-exposed patients. One patient presented with trisomy of chromosomes 1, 7, and 11, while trisomy of chromosome 7 was observed in one patient. There were two patients with trisomy of chromosome 1. Trisomy of chromosomes 1, 7, 11, and 17 was not observed in the cervicovaginal tissue taken from control patients. These data suggest that DES-induced chromosomal trisomy may be an early event in the development of cervicovaginal neoplasia in humans.

Genetic imbalances in endometrial hyperplasia and endometrioid carcinoma detected by comparative genomic hybridization

OBJECTIVE

To evaluate the sequential genomic copy alterations related to the development of precursor lesions and endometrioid-type endometrial carcinomas, and its association with cellular atypia.

STUDY DESIGN

Paraffin-embedded tissue specimens from 32 cases of endometrial hyperplasia, 15 of endometrial carcinoma, and 20 of normal endometrial tissue were retrospectively evaluated by the comparative genomic hybridization (CGH) technique. The average number of copy alterations (ANCA) index was used to define the incidence of genomic imbalances in each tissue group. Identified sequential genetic abnormalities were compared with the final histopathological diagnosis and the cellular atypia.

RESULTS

Detectable and consistent chromosomal imbalances were found in 13 hyperplasia and 9 carcinoma specimens. There was a significant correlation between ANCA value and degree of cellular atypia and tumor grade. While 1p36-pter, 20q deletions, and 4q overrepresentation were the most prevalent imbalances detected in both complex hyperplasia and complex atypical hyperplasia, 17q22-qter deletion and amplification of 2p34 were only seen in hyperplasia with atypical cells. Overrepresentations of chromosomes 8q, 1q, and 3q are the most frequent aberrations in endometrial carcinomas, but were absent from all the precursor lesions except one. Underrepresentations of chromosomes 1p36-pter and 10q are the other commonly seen aberrations in carcinomas, the latter being more frequent in moderately differentiated than in poorly differentiated lesions.

CONCLUSIONS

Different patterns of chromosomal aberrations are seen in precursor lesions than in endometrial carcinomas, except for the loss of 1p36-pter. The presence of 1p deletion in both endometrial hyperplasia and cancer specimens suggests that this is an early event in the development of carcinoma. These results support a stepwise mode of tumorigenesis with accumulation of a series of genomic copy alterations in endometrial carcinogenesis.

Overexpression of h-prune in Breast Cancer is Correlated with Advanced Disease Status

Purpose: The h-prune gene is involved in cellular motility and metastasis formation in breast cancer through interacting with the nm23-H1 protein. The aim of this study was to better define the clinical and pathologic role of h-prune in breast cancer patients.

Experimental Design: Using immunohistochemistry, we assessed h-prune and nm23-H1 protein expression in two series of breast cancer patients: (i) in 2,109 cases with pathologic reports on primary tumors and (ii) in 412 cases with detailed clinical information. To assess the role of DNA amplification in gene activation, the h-prune copy number was evaluated by fluorescence in situ hybridization analysis in 1,016 breast cancer cases.

Results: In the patients tested (n = 2,463), 1,340 (54%) had an increased level of h-prune expression; a positive immunostaining for nm23-H1 was observed in 615 of 2,061 (30%) cases. Overexpression of h-prune was associated with multiple gene copy number at chromosome 1q21.3 in a very limited fraction of cases (68 of 1,016; 6.7%), strongly indicating that alternative pathways induce h-prune activation in breast cancer. Multivariate Cox regression analysis showed that neither h-prune overexpression nor decreased nm23-H1 immunostaining is independent prognostic factors. However, a significant association of h-prune overexpression with either advanced lymph node status (P = 0.017) or presence of distant metastases (P = 0.029) was observed.

Conclusions: Although not significantly correlated with overall survival, positive h-prune immunostaining identifies subsets of breast cancer patients with higher tumor aggressiveness. Further investigations using larger collections of advanced breast cancer patients are required for assessing the predictive role of h-prune in breast cancer.

High frequency of genomic instability in Ewing family of tumors

We tested Ewing sarcoma tumors for microsatellite instability (MSI) and loss of heterozygosity (LOH) to investigate the role of genomic instability (GI) in this sarcoma. We detected a high frequency of GI (57%), mostly on 1p and 11p, 35% and 30%, respectively. Patients with GI compared to those with stable genome had a median progression-free survival (PFS) and overall survival (OS) of 24 months and 70 months, compared with 39 and 84 months, respectively. MSI was observed in 48% (11/23) of the tumor samples. Low-MSI (L-MSI) patients (with MSI presented at only one locus) tended to have a better prognosis, 70% PFS, compared with 25% in the high-MSI (H-MSI) group (P=0.13). LOH without MSI did not correlate with progression. H-GI (MSI and/or LOH in > or =30% of tested markers) tended to associate with an adverse prognosis (P=0.28), and correlated significantly with the pelvic site of the primary tumor (P=0.02). The instability of 1p was not associated with progression, while alterations at the 11p locus tended to correlate with a more aggressive disease (P=0.18). Our data suggest that GI may play a role in Ewing sarcoma clinical behavior and outcome.

MSI-low, a real phenomenon which varies in frequency among cancer types

This study assessed whether low-level microsatellite instability (MSI-L) is a phenomenon specific to colorectal cancers or is also present in other tumour types. Breast (grade III ductal and lobular), endometrial and ovarian carcinomas, as well as colorectal cancers, were analysed for MSI-L using eight microsatellite markers. The markers were selected from a panel that had previously been shown to be sensitive for the detection of MSI-L in colorectal cancers. It was found that MSI-L was present in 30 of 87 (35%) colorectal cancers, 2 of 59 (3%) grade III breast carcinomas, 1 of 35 (3%) lobular breast cancers, 16 of 50 (32%) endometrial cancers, and 9 of 34 (26%) ovarian cancers. These results suggest that MSI-L is a very rare occurrence in breast carcinomas, but does occur as a real phenomenon in colorectal, endometrial, and ovarian carcinomas, which are all part of the hereditary non-polyposis colon cancer (HNPCC) syndrome. PCR artefact was also found to masquerade as MSI-L; criteria for the assessment of MSI-L are suggested to eliminate this problem.

Mutation analysis of candidate genes in melanoma-prone families

Putative tumour suppressor genes CDKN2A and CDKN2B (on chromosome 9p21) and CDKN2A-interacting cell growth regulatory genes CDK4 and Id-1 have been demonstrated to be involved in the pathogenesis of malignant melanoma (MM). Mutation analysis of these candidate genes was performed in MM families from southern Italy with three or more affected members or two affected members and one or more relative with histologically diagnosed atypical naevus. Two CDKN2A mutations, Arg24Pro and 1-292 G>A, were observed in two (15%) families; except for CDKN2A and Id-1 polymorphisms, no sequence variations were detected in the remaining genes. Screening among 119 sporadic MM cases revealed two additional CDKN2A mutations at very low prevalences. Identification of a large shared haplotype at 9p21 in some MM families negative for CDKN germline mutations suggests that other CDKN-inactivating mechanisms may be responsible for MM predisposition or, alternatively, additional susceptibility gene(s) may be present on chromosome 9p21. Fluorescence in situ hybridization analysis of a subset of MM tissue sections seemed to indicate that the D9S171 locus may be involved in MM pathogenesis.