Impact of microsatellite instability (MSI) on survival in high grade endometrial carcinoma

Amide Proton Transfer-Weighted Imaging Combined With Intravoxel Incoherent Motion for Evaluating Microsatellite Instability in Endometrial Cancer

BACKGROUND

Microsatellite instability (MSI), caused by mismatch repair (MMR) protein defects that lead to uncorrectable mismatch bases, results in the accumulation of gene mutations and ultimately to tumors. Preoperative prediction of MSI can provide a basis for personalized and precise treatment of endometrial cancer (EC) patients.

PURPOSE

To investigate amide proton transfer weighting (APTw) imaging combined with intravoxel incoherent motion (IVIM) in the assessment of MSI in EC.

STUDY TYPE

Retrospective.

POPULATION

A total of 71 patients with EC (12 classified as the MSI group and 22 as the microsatellite stabilization [MSS] group after entering and leaving the group standard).

FIELD STRENGTH/SEQUENCE

A 3.0 T/IVIM, diffusion-weighted imaging (DWI) and APTw.

ASSESSMENT

Amide proton transfer (APT) value, apparent diffusion coefficient (ADC), pure diffusion coefficient (D), pseudo diffusion coefficient (D*), and perfusion fraction (f) were calculated and compared between MSI and MSS groups.

STATISTICAL TESTS

The Kendall's W test; Mann-Whitney U-test; Chi-square test or Fisher's exact test; logistic regression analysis; Area under the receiver operating characteristic (ROC) curve (AUC); The Delong test; Pearson or Spearman correlation coefficients. The significance threshold was set at P < 0.05.

RESULTS

APT and D* values of the MSI group were significantly higher than those of the MSS group. While ADC, D, and f values in the MSI group were significantly lower than those in the MSS group. The multivariate analysis revealed that only APT and D* values were independent predictors to evaluate the MSI status. And the ROC curves indicated that the combination of APT and D* values could distinguish the MSI status of EC with the highest diagnostic efficacy (AUC = 0.973), even without significant difference to those by APT (AUC = 0.894) or D* (AUC = 0.920) value separately (P = 0.149 and 0.078, respectively).

CONCLUSION

Combination of APTw and IVIM imaging may serve as an effective noninvasive method for clinical assessment of MSI in EC.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 2.

Frequency of microsatellite instability (MSI) in upper tract urothelial carcinoma: comparison of the Bethesda panel and the Idylla MSI assay in a consecutively collected, multi-institutional cohort

AIMS

Upper tract urothelial carcinoma (UTUC) is a rare malignancy with a poor prognosis which occurs sporadically or in few cases results from a genetic disorder called Lynch syndrome. Recently, examination of microsatellite instability (MSI) has gained importance as a biomarker: MSI tumours are associated with a better response to immunomodulative therapies. Limited data are known about the prevalence of MSI in UTUC. New detection methods using the fully automated Idylla MSI Assay facilitate analysis of increased patient numbers.

METHODS

We investigated the frequency of MSI in a multi-institutional cohort of 243 consecutively collected UTUC samples using standard methodology (Bethesda panel), along with immunohistochemistry of mismatch repair (MMR) proteins. The same tumour cohort was retested using the Idylla MSI Assay by Biocartis.

RESULTS

Using standard methodology, 230/243 tumours were detected as microsatellite stable (MSS), 4/243 tumours as MSI and 9/243 samples as invalid. In comparison, the Idylla MSI Assay identified four additional tumours as MSS, equalling 234/243 tumours; 4/243 were classified as MSI and only 5/243 cases as invalid. At the immunohistochemical level, MSI results were supported in all available cases with a loss in MMR proteins. The overall concordance between the standard and the Idylla MSI Assay was 98.35%. Time to result differed between 3 hours for Idylla MSI Assay and 2 days with the standard methodology.

CONCLUSION

Our data indicate a low incidence rate of MSI tumours in patients with UTUC. Furthermore, our findings highlight that Idylla MSI Assay can be applied as an alternative method of MSI analysis for UTUC.

Response to first line platinum-based chemotherapy in mismatch repair deficient (MMRd)/ microsatellite instability high (MSI-high) endometrial carcinoma

BACKGROUND

Around 15% of metastatic endometrial carcinoma (EC) are MMRd/MSI-H improving response to immune checkpoint inhibitors (ICI). So far, few data existed considering the chemotherapy (CT) sensitivity in MMRd/MSI-H EC, especially response to first-line platinum-based treatment.

PATIENTS AND METHODS

We performed a multicentric retrospective analysis reporting the response to first line platinum CT in MMRd/MSI-H EC patients. The primary endpoints were objective response rate (ORR) and progression-free survival (PFS) with first line platinum-based CT.

RESULTS

A total of 112 patients MMRd/MSI-H EC from 8 centers were identified. Median overall survival was 58.0 months (95% CI: 45.3-95.1). Among them, 78 patients received first line platinum CT in recurrent/metastatic setting. With a median follow up of 32.6 months (min: 0.03; max: 135.0), ORR and DCR (disease control rate) were 50% (95% CI: 38.5-61.5) and 68% (95% CI: 56.4-78.1), respectively. Median PFS and OS from first line platinum-based CT was 7.8 months (95% CI: 6.0-9.0) and 51.9 months (95% CI: 28.0-NE), respectively. Median PFS with ICI in second line (n = 48) was 10.7 months (95% CI: 3.4-NE) from ICI initiation.

CONCLUSION

ORR in first line metastatic MMRd/MSI-H EC is consistent with efficacy in an all comer metastatic EC population.

The Role of Immunohistochemistry Markers in Endometrial Cancer with Mismatch Repair Deficiency: A Systematic Review

The objective of this systematic review was to summarize our current knowledge of the role of immunohistochemistry (IHC) markers for identifying mismatch repair-deficient (MMRd) tumors in endometrial cancer (EC). Identification of MMRd tumors, which occur in 13% to 30% of all ECs, has become critical for patients with colorectal and endometrial cancer for therapeutic management, clinical decision making, and prognosis. This review was conducted by two authors applying the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using the following terms: “immunohistochemistry and microsatellite instability endometrial cancer” or “immunohistochemistry and mismatch repair endometrial cancer” or “immunohistochemistry and mismatch repair deficient endometrial cancer”. Among 596 retrieved studies, 161 fulfilled the inclusion criteria. Articles were classified and presented according to their interest for the diagnosis, prognosis, and theragnostics for patients with MMRd EC. We identified 10, 18, and 96 articles using IHC expression of two, three, or four proteins of the MMR system (MLH1, MSH2, MHS6, and PMS2), respectively. MLH1 promoter methylation was analyzed in 57 articles. Thirty-four articles classified MMRd tumors with IHC markers according to their prognosis in terms of recurrence-free survival (RFS), overall survival (OS), stage, grade, and lymph node invasion. Theragnostics were studied in eight articles underlying the important concentration of PD-L1 in MMRd EC. Even though the role of IHC has been challenged, it represents the most common, robust, and cheapest method for diagnosing MMRd tumors in EC and is a valuable tool for exploring novel biotherapies and treatment modalities.

Mismatch repair deficiency and clinicopathological characteristics in endometrial carcinoma: a systematic review and meta-analysis

Background

Loss of mismatch repair (MMR) occurs frequently in endometrial carcinoma (EC) and is an important prognostic marker. However, the frequency of MMR deficiency (D-MMR) in EC remains inconclusive. This systematic review and meta-analysis addressed this inconsistency and evaluated related clinicopathology.

Methods

Electronic databases were searched for articles: PubMed, Science Direct, Web of Science, EMBASE, and the Wiley Online Library. Data were extracted from 25 EC studies of D-MMR to generate a clinical dataset of 7,459 patients. A random-effects model produced pooled estimates of D-MMR EC frequency with 95% confidence interval (CI) for meta-analysis.

Results

The overall pooled proportion of D-MMR was 24.477% (95% CI, 21.022 to 28.106) in EC. The Lynch syndrome subgroup had 22.907% pooled D-MMR (95% CI, 14.852 to 32.116). D-MMR was highest in type I EC (25.810) (95% CI, 22.503 to 29.261) compared to type II (13.736) (95% CI, 8.392 to 20.144). Pooled D-MMR was highest at EC stage and grades I–II (79.430% and 65.718%, respectively) and lowest in stages III–IV and grade III (20.168% and 21.529%). The pooled odd ratios comparing D-MMR to proficient MMR favored low-stage EC disease (1.565; 0.894 to 2.740), lymphovascular invasion (1.765; 1.293 to 2.409), and myometrial invasion >50% (1.271; 0.871 to 1.853).

Conclusions

Almost one-quarter of EC patients present with D-MMR tumors. The majority has less aggressive endometrioid histology. D-MMR presents at lower tumor stages compared to MMR-proficient cases in EC. However other metastatic parameters are comparatively higher in the D-MMR disease setting.

Cost-effectiveness of pembrolizumab compared with chemotherapy in the US for women with previously treated deficient mismatch repair or high microsatellite instability unresectable or metastatic endometrial cancer

AIMS

There is limited published evidence for the cost-effectiveness of treatments for unresectable or metastatic endometrial cancer (mEC). The objective of this analysis was to assess the cost-effectiveness of pembrolizumab versus chemotherapy for previously treated unresectable or mEC, in women whose tumors have deficient mismatch repair (dMMR) or high microsatellite instability (MSI-H). The analysis was carried out from a US healthcare payer perspective.

MATERIALS AND METHODS

A lifetime partitioned survival model comprising three health states (progression-free, progressed disease and death) was constructed. Chemotherapy was represented by single-agent paclitaxel or doxorubicin. Overall survival, progression-free survival and time on treatment data for pembrolizumab were obtained from a Phase II clinical study that included women with previously treated dMMR/MSI-H unresectable or mEC (KEYNOTE-158, NCT02628067). Survival data for chemotherapy were obtained from a published Phase III study for previously treated advanced endometrial cancer. Costs included were drug acquisition and administration, health-state, end-of-life, and adverse event management. Costs were presented in 2019 US$. Outcomes were calculated as quality-adjusted life-years (QALYs), using EQ-5D data from KEYNOTE-158. Model results were tested extensively in deterministic and probabilistic sensitivity analyses.

RESULTS

Results demonstrated that pembrolizumab is a highly cost-effective treatment option when compared with chemotherapy, with estimated deterministic and probabilistic incremental cost-effectiveness ratios (ICERs) of $58,165 and $57,668 per QALY gained, respectively. Pembrolizumab was associated with a large QALY and life-year gain per person versus chemotherapy over the model time horizon (deterministic 4.68 life year gain, 3.80 QALYs), with the majority of QALYs accrued in the progression-free health state.

LIMITATIONS

The key limitation of the analysis was the lack of comparative effectiveness data for pembrolizumab versus chemotherapy.

CONCLUSIONS

Pembrolizumab is a highly cost-effective treatment option when compared with chemotherapy for women with previously treated dMMR/MSI-H unresectable or mEC. Results were robust to the changes in parameters and assumptions explored.

A Novel Next-Generation Sequencing Approach to Detecting Microsatellite Instability and Pan-Tumor Characterization of 1000 Microsatellite Instability-High Cases in 67,000 Patient Samples

Microsatellite instability (MSI) is an important biomarker for predicting response to immune checkpoint inhibitor therapy, as emphasized by the recent checkpoint inhibitor approval for MSI-high (MSI-H) solid tumors. Herein, we describe and validate a novel method for determining MSI status from a next-generation sequencing comprehensive genomic profiling assay using formalin-fixed, paraffin-embedded samples. This method is 97% (65/67) concordant with current standards, PCR and immunohistochemistry. We further apply this method to >67,000 patient tumor samples to identify genes and pathways that are enriched in MSI-stable or MSI-H tumor groups. Data show that although rare in tumors other than colorectal and endometrial carcinomas, MSI-H samples are present in many tumor types. Furthermore, the large sample set revealed that MSI-H tumors selectively share alterations in genes across multiple common pathways, including WNT, phosphatidylinositol 3-kinase, and NOTCH. Last, MSI is sufficient, but not necessary, for a tumor to have elevated tumor mutation burden. Therefore, MSI can be determined from comprehensive genomic profiling with high accuracy, allowing for efficient MSI-H detection across all tumor types, especially those in which routine use of immunohistochemistry or PCR-based assays would be impractical because of a rare incidence of MSI. MSI-H tumors are enriched in alterations in specific signaling pathways, providing a rationale for investigating directed immune checkpoint inhibitor therapies in combination with pathway-targeted therapies.

Microsatellite instability in endometrial cancer: New purpose for an old test

Historically, microsatellite instability testing has been used to identify endometrial cancer patients with Lynch Syndrome. Now, it is also being used to identify those who may be immunotherapy candidates.

A potpourri of pathogenetic pathways in endometrial carcinoma with a focus on Lynch Syndrome

Endometrial carcinoma is the most frequently occurring female genital tract malignancy in developed nations, with a rising annual incidence. Endometrioid endometrial carcinoma (EEC), the most common histological variant, differs in morphologic and molecular characteristics from serous carcinomas but morphological distinction of high-grade EECs from serous carcinomas may prove difficult. Thus, molecular categorization of tumors may allow for better tumor classification with greater insight into the underlying biology of endometrial carcinomas with new therapeutic options. Microsatellite instability (MSI) is a commonly occurring molecular aberration in EECs and has been identified in most Lynch Syndrome (LS) associated tumors. This tumor syndrome predisposes afflicted individuals to a myriad of tumors including endometrial carcinoma. Herein, the molecular signature of endometrial tumors as well as LS, and its clinical manifestations are reviewed. Understanding of the pathogenetic pathways allows for greater comprehension of occurrences at a molecular level which are then appreciated at a cellular and tissue level, by the histopathologist. The molecular classification of endometrial tumors allows for further targeted therapeutic options for affected patients. Screening tests for patients with suspected LS enables surveillance of other tumors in the affected patient and her family with the potential to decrease morbidity and mortality. It is envisioned that this overview will allow for enhanced comprehension of genetic pathways by practicing pathologists, oncologists, gynecologists and other members of the multidisciplinary team, all of whom are involved in the management of the patient with an endometrial malignancy.

Prognostic values of DNA mismatch repair genes in ovarian cancer patients treated with platinum-based chemotherapy

Purpose

DNA mismatch repair (MMR) is a highly conserved biological pathway that plays a key role in maintaining genomic stability. MMR has been reported as a prognostic marker in certain cancers; however, the results are controversial. Therefore, identification of the prognostic value of MMR genes in ovarian cancer based on a large sample size is pivotal.

Methods

In the current study, we systemically investigated the prognostic roles of seven MMR genes, MSH2, MSH3, MSH6, MLH1, MLH3, PMS1 and PMS2, in ovarian cancer patients treated with platinum-based chemotherapy through “The Kaplan–Meier plotter” (KM plotter) database, which contains gene expression data and survival information of ovarian cancer patients.

Results

Among seven MMR genes, high mRNA levels of MSH6, MLH1 and PMS2 were significantly associated with a better overall survival for all ovarian cancer patients treated with platinum-based chemotherapy, especially in late-stage and poor-differentiated ovarian cancer patients. Increased MSH6 and PMS2 mRNA expression was correlated with a favorable overall survival in serous ovarian cancer patients.

Conclusions

Our results indicate that sufficient MMR system is associated with an improved survival in ovarian cancer treated with platinum-based chemotherapy. MMR gene may be a potential prognosis predictor in ovarian cancer.

The significance of markers in the diagnosis of endometrial cancer

Endometrial cancer is one of the most common cancers experienced by women throughout the world. It is also the most common malignancy within the female reproductive system, representing 37.7% of all disorders. The incidence increases with age, and is diagnosed most frequently in women between 45 and 65 years old. In the last few years, numerous studies have been performed to identify tumour biomarkers. Biomarkers include not only protein routinely used as tumour markers but also genes and chromosomes. The limiting factor in the use of markers in the diagnosis of endometrial cancer is their lack of specificity. However, specific markers for endometrial cancer are the subject of much research attention. Although moderately elevated levels of markers are present in a number of inflammatory or non-malignant diseases, significantly increased levels of markers indicate the development of cancer. Recently, research has been focused on the identification of molecular changes leading to different histological subtypes of endometrial cancer. In this paper the authors reviewed several currently investigated markers. Progress in these investigations is very important in the diagnostics and treatment of endometrial cancer. In particular, the identification of novel mutations and molecular profiles should enhance our ability to personalise adjuvant treatment with genome-guided targeted therapy.

Update on pathology, staging and molecular pathology of endometrial (uterine corpus) adenocarcinoma

Endometrial carcinoma is comprised of two major groups: type I that is hormonally driven with a good prognosis and type II that is hormone independent with a poor prognosis. The two most common subtypes are endometrioid adenocarcinoma, the prototypic type I cancer, and uterine serous carcinoma, the prototypic type II cancer, each with their own distinct precursor lesion. The histologic type, as codified by the WHO Tumor Classification system, grade, and stage are used to guide treatment. There is an increasing interest in screening for familial risk factors, specifically Lynch syndrome. A molecular classification of endometrial cancers holds promise for future improvements in care.

Refining prognosis and identifying targetable pathways for high-risk endometrial cancer; a TransPORTEC initiative

This study aimed to investigate whether molecular analysis can be used to refine risk assessment, direct adjuvant therapy, and identify actionable alterations in high-risk endometrial cancer. TransPORTEC, an international consortium related to the PORTEC3 trial, was established for translational research in high-risk endometrial cancer. In this explorative study, routine molecular analyses were used to detect prognostic subgroups: p53 immunohistochemistry, microsatellite instability and POLE proofreading mutation. Furthermore, DNA was analyzed for hotspot mutations in 13 additional genes (BRAF, CDKNA2, CTNNB1, FBXW7, FGFR2, FGFR3, FOXL2, HRAS, KRAS, NRAS, PIK3CA, PPP2R1A, and PTEN) and protein expression of ER, PR, PTEN, and ARID1a was analyzed. Rates of distant metastasis, recurrence-free, and overall survival were calculated using the Kaplan-Meier method and log-rank test. In total, samples of 116 high-risk endometrial cancer patients were included: 86 endometrioid; 12 serous; and 18 clear cell. For endometrioid, serous, and clear cell cancers, 5-year recurrence-free survival rates were 68%, 27%, and 50% (P=0.014) and distant metastasis rates 23%, 64%, and 50% (P=0.001), respectively. Four prognostic subgroups were identified: (1) a group of p53-mutant tumors; (2) microsatellite instable tumors; (3) POLE proofreading-mutant tumors; and (4) a group with no specific molecular profile (NSMP). In group 3 (POLE-mutant; n=14) and group 2 (microsatellite instable; n=19) patients, no distant metastasis occurred, compared with 50% distant metastasis rate in group 1 (p53-mutant; n=36) and 39% in group 4 (NSMP; P<0.001). Five-year recurrence-free survival was 93% and 95% for group 3 (POLE-mutant) and group 2 (microsatellite instable) vs 42% (group 1, p53-mutant) and 52% (group 4, NSMP; P<0.001). Targetable FBXW7 and FGFR2 mutations (6%), alterations in the PI3K-AKT pathway (60%) and hormone receptor positivity (45%) were frequently found. In conclusion, molecular analysis of high-risk endometrial cancer identifies four distinct prognostic subgroups, with potential therapeutic implications. High frequencies of targetable alterations were identified and may serve as targets for individualized treatment.

Mismatch repair status and clinical outcome in endometrial cancer: a systematic review and meta-analysis

BACKGROUND

The association between the deficiency in mismatch repair (MMR) genes and prognosis in women with endometrial cancer is unclear. Here we report a systematic review and meta-analysis exploring this association.

METHODS

We searched literature databases (MEDLINE, EMBASE, and Cochrane) from 1980 until December 2011 to identify studies evaluating the association between MMR status and clinical outcome in endometrial cancer. The main outcome measures were overall survival (OS) and disease-free survival (DFS).

RESULTS

Twenty-three studies met the inclusion criteria. The median sample size of studies was 112, 74% were retrospective case-series and 70% performed microsatellite instability (MSI) analysis to evaluate the status of MMR. Only 22% of studies used the panel of five microsatellite markers recommended by the National Cancer Institute. Seven studies used immunohistochemistry to define MMR deficiency, but only two of them determined the expression of all four MMR proteins. Overall, significant associations between MMR and outcome were observed in 32% of studies. There was marked inter-study heterogeneity for estimates of OS and DFS. Pooled analysis did not show any significant association between deficiency in MMR and worse OS (6 studies, hazard ratio [HR] 2.0, p=0.11) or DFS (4 studies, HR ratio 1.31, p=0.66).

CONCLUSION

There is no definitive evidence of a significant association between MMR status and detrimental survival in endometrial cancer.

Clinicopathologic analysis of loss of AT-rich interactive domain 1A expression in endometrial cancer

Loss of the AT-rich interactive domain 1A (a putative tumor suppressor) protein BAF250a has recently been described as a frequent event in endometrial carcinoma. In this study, we determined the significance of the loss of AT-rich interactive domain 1A immunoreactivity for several clinicopathologic features of uterine endometrioid carcinoma. AT-rich interactive domain 1A expression was assessed by immunohistochemistry using 111 paraffin-embedded tissue specimens and clinical data collected by a retrospective medical record review. The correlations between loss of AT-rich interactive domain 1A protein and clinicopathologic and prognostic features were examined. In addition, the expression of PTEN, p53, Her2, and MLH1 was assessed by immunohistochemistry and compared with AT-rich interactive domain 1A expression. AT-rich interactive domain 1A immunoreactivity was undetectable in 27 (24%) of 111 analyzed endometrioid endometrial carcinomas. There was no significant difference between negative and positive cases of AT-rich interactive domain 1A in terms of any clinicopathologic features examined (International Federation of Gynecology and Obstetrics stage, grade, depth of myometrial invasion, lymph node metastasis, lymphovascular space invasion, body mass index, postmenopausal status, patient age at diagnosis, and estrogen and progesterone receptor status). The comparison between the expression of AT-rich interactive domain 1A and the expression of PTEN, p53, Her2, and MLH1 also revealed no significant association. There was no significant correlation between AT-rich interactive domain 1A expression and progression-free/overall survival of patients. This study provides the first examination of the clinicopathologic relationship between AT-rich interactive domain 1A protein expression and endometrial carcinoma. No significant differences between positive and negative cases of AT-rich interactive domain 1A were observed with respect to any clinicopathologic features or patient survival.

Loss of HLA class I and mismatch repair protein expression in sporadic endometrioid endometrial carcinomas

Tumor cells can escape from cytotoxic T-cell responses by downregulation of human leukocyte antigen (HLA) class I molecules expressed at the cell surface which has been associated with a deficient mismatch repair (MMR) system in colorectal carcinomas. Our study investigated the association between expression of MMR proteins and HLA class I in sporadic endometrioid endometrial carcinomas (EC). In a consecutively selected cohort of 486 EC patients, MMR proteins (MLH1, MSH2 and MSH6) and HLA class I (HLA-A, -B, -C or β(2) m) were investigated by immunohistochemistry. Expression levels of MMR proteins and HLA class I were compared between low-grade and high-grade ECs. HLA class I expression was compared between tumors with loss (negative immunostaining of ≥1 MMR protein) and expression of MMR proteins. Associations between previously determined numbers of intratumoral CD8(+) T-lymphocytes and expression of MMR proteins and HLA class I and the influence on survival was determined. ECs with loss of MMR protein expression (33.5%) more frequently have loss of HLA-B/C (37.3%), compared to ECs with MMR protein expression (25.5%, p = 0.007). Patients with loss of MMR proteins have a worse disease-specific survival compared to patients with expression (p = 0.039). CD8(+) T-lymphocytes have a positive influence on disease-free and disease-specific survival in the total EC cohort but not in patients with loss of MMR protein expression. In conclusion, our results indicate that loss of MMR protein expression is related to selective downregulation of HLA class I which contributes to immune escape in EC with an abnormal MMR system.

Molecular markers and clinical behavior of uterine carcinosarcomas: focus on the epithelial tumor component

Carcinosarcomas (malignant mixed Müllerian tumors) of the uterus are rare and aggressive malignancies consisting of an epithelial (carcinoma) and a mesenchymal (sarcoma) tumor component and are considered as metaplastic endometrial carcinomas. This study evaluated molecular characteristics and clinical behavior of uterine carcinosarcomas to improve treatment regimens in the future. Immunohistochemical expression of estrogen receptor-α and -β, progesterone receptor-A and -B, MLH1, MSH2, MSH6, PTEN (phosphatase and tensin homolog deleted on chromosome 10), p53, β-catenin and cyclin D1 was determined in 40 uterine carcinosarcomas. Immunostaining was compared between epithelial and mesenchymal tumor components. To determine the prognostic role of the epithelial component, clinicopathological data and survival were compared between patients with endometrioid and non-endometrioid epithelial tumor components. To determine prognosis of carcinosarcomas compared with high-risk endometrial carcinomas, clinicopathological characteristics and survival were compared between these patients. Hormone receptor expression occurred infrequently: estrogen receptor-α (8%) and -β (32%), progesterone receptor-A (0%) and -B (23%), next to β-catenin (4%) and cyclin D1 (7%). PTEN, MLH1, MSH2 and MSH6 mutations occurred in 39%, 33%, 22% and 21%, respectively (based on absent immunostaining). Overexpression of p53 was observed in 38%. Expression patterns of p53, MSH2 and MSH6 corresponded between epithelial and mesenchymal tumor components. In our cohort, the epithelial component caused the majority of metastases (72%) and vascular invasion (70%). Survival tended to be worse for patients with a non-endometrioid epithelial component compared with an endometrioid epithelial component (5-year survival: 26% and 55%, respectively). Survival was worse for patients with uterine carcinosarcomas compared with high-risk endometrial carcinomas (grade 3 endometrioid and non-endometrioid); 5-year survival rates: 42%, 77% and 57%, respectively. Our results support the monoclonal origin of uterine carcinosarcomas. The epithelial component determines prognosis by causing the majority of metastases and vascular invasion. To improve prognosis, treatment should focus on the epithelial tumor component of uterine carcinosarcomas.

DNA repair pathways and their implication in cancer treatment

Many cytotoxic agents used in cancer treatment exert their effects through their ability to directly or indirectly damage DNA and thus resulting in cell death. Major types of DNA damage induced by anticancer treatment include strand breaks (double or single strand), crosslinks (inter-strand, intra-strand, DNA-protein crosslinks), and interference with nucleotide metabolism and DNA synthesis. On the other hand, cancer cells activate various DNA repair pathways and repair DNA damages induced by cytotoxic drugs. The purpose of the current review is to present the major types of DNA damage induced by cytotoxic agents, DNA repair pathways, and their role as predictive agents, as well as evaluate the future perspectives of the novel DNA repair pathways inhibitors in cancer therapeutics.

Promoter hypermethylation of CIDEA, HAAO and RXFP3 associated with microsatellite instability in endometrial carcinomas

OBJECTIVE

DNA promoter methylation is an epigenetic phenomenon for long-term gene silencing during tumorigenesis. The purpose of this study is to identify novel hypermethylated loci associated with clinicopathologic variables in endometrioid endometrial carcinomas.

METHODS

To find hypermethylated promoter loci, we used differential methylation hybridization coupling with microarray and further validated by combined bisulfite restriction analysis and MassARRAY assay. Methylation levels of candidate loci were corrected with clinicopathologic factors of endometrial carcinomas.

RESULTS

Increased promoter methylation of CIDE, HAAO and RXFP3 was detected in endometrial carcinomas compared with adjacent normal tissues, and was associated with decreased gene expression of all three genes. In a clinical cohort, promoter hypermethylation on CIDEA, HAAO and RXFP3 was detected in 85, 63 and 71% of endometrial carcinomas, respectively (n=118, P<0.001) compared with uninvolved normal endometrium. Methylation status of CIDEA, HAAO and RXFP3 had significant association with microsatellite instability in tumors (P<0.001). Furthermore, methylation levels of HAAO were further found to relate to disease-free survivals (P=0.034).

CONCLUSIONS

Hypermethylation of CIDEA, HAAO and RXFP3 promoter regions appears to be a frequent event in endometrial carcinomas. Hypermethylation at these loci is strongly associated with microsatellite instability status. Moreover, HAAO methylation predicts disease-free survival in this cohort of patients with endometrioid endometrial cancer.

Genome-wide single-nucleotide polymorphism arrays in endometrial carcinomas associate extensive chromosomal instability with poor prognosis and unveil frequent chromosomal imbalances involved in the PI3-kinase pathway

Endometrial cancer is one of the tumor types in which either chromosomal instability (CIN) or microsatellite instability (MSI) may occur. It is known to possess mutations frequently in the Ras-PI3K (phosphatidylinositol 3'-kinase) pathway. We performed a comprehensive genomic survey in 31 endometrial carcinomas with paired DNA for chromosomal imbalances (25 by the 50K and 6 by the 250K single-nucleotide polymorphism (SNP) array), and screened 25 of the 31 samples for MSI status and mutational status in the Ras-PI3K pathway genes. We detected five or more copy number changes (classified as CIN-extensive) in 9 (29%), 1 to 4 changes (CIN-intermediate) in 17 (55%) and no changes (CIN-negative) in 5 (16%) tumors. Positive MSI was less common in CIN-extensive tumors (14%), compared with CIN-intermediate/negative tumors (50%), and multivariate analysis showed that CIN-extensive is an independent poor prognostic factor. SNP array analysis unveiled copy number neutral LOH at 54 loci in 13 tumors (42%), including four at the locus of PTEN. In addition to eight (26%) tumors with PTEN deletions, we detected chromosomal imbalances of NF1, K-Ras and PIK3CA in four (13%), four (13%) and six (19%) tumors, respectively. In all, 7 of the 9 CIN-extensive tumors harbor deletions in the loci of PTEN and/or NF1, whereas all the 10 MSI-positive tumors possess PTEN, PIK3CA and/or K-Ras mutations. Our results showed that genomic alterations in the Ras-PI3K pathway are remarkably widespread in endometrial carcinomas, regardless of the type of genomic instability, and suggest that the degree of CIN is a useful biomarker for prognosis in endometrial carcinomas.