K-ras mutations in endometrial carcinomas with microsatellite instability

Molecular features for timely cancer diagnosis and treatment - tumors of the ovary, fallopian tube and endometrium

Gynecologic pathology has moved, within only a few years, from being a diagnostic area devoid of molecular testing into a diagnostic discipline in which such analyses are becoming routine. The direct relevance of molecular characterization to the choice of treatment of patients with carcinomas originating in both the uterus and adnexae makes it likely that such testing will only expand along with our understanding of the molecular make-up of these tumors. As a consequence, gynecologic pathologists have become an integral part of patient management, rather than lab personnel providing external services.In parallel, molecular testing is expanding as a tool for diagnosing rare tumors affecting these organs, including soft tissue tumors, sex cord-stromal tumors and germ cell tumors, as well as other rare entities. Increased knowledge in this area bears directly on the ability to diagnose these tumors in a reproducible manner, as well as recognize and consult on genetic diseases. Hopefully, despite the inherent difficulty in studying rare cancers, it will also translate into new therapeutic options for the malignant ones among these rare cancers.

GNA14 stimulation of KLF7 promotes malignant growth of endometrial cancer through upregulation of HAS2

BACKGROUND

Endometrial cancer (UCEC) is one of the most common gynecological malignancies. We previously found that overexpression of G protein α subunit 14 (GNA14) promoted UCEC growth. Krüppel-like factor 7 (KLF7) acts as an oncogene in various cancer types, whereas the connection between GNA14 and KLF7 in UCEC is unclear. We herein explored the involvement of GNA14/KLF7 in UCEC development.

METHODS

Clinical relevance of GNA14, KLF7 and HAS2 in UCEC was analyzed from TCGA and by immunohistochemical staining. Knockdown and overexpression of indicated genes were conducted by transfecting the cells with siRNAs and lentivirus, respectively. mRNA and protein expression was detected by qRT-PCR and Western blot. CCK8, colony formation, cell cycle, apoptosis, transwell and wound healing were performed to check cell biology function in vitro. Tumor growth in nude mice was conducted to check in vivo function. RNA sequencing was used to determine dys-regulated genes.

RESULTS

We demonstrated that GNA14 stimulated the expression of KLF7 in UCEC cells. There was a positive correlation between GNA14 and KLF7 in normal and UCEC tissues. In vitro, KLF7 promoted cell proliferation, colony formation, cell cycle progression, and migration of UCEC cells. Apoptosis was inhibited by KLF7. Xenografted tumorigenesis of UCEC cells was suppressed by KLF7 knockdown. Furthermore, RNA sequencing results showed that KLF7 regulated the expression of a large amount of genes, among which hyaluronan synthase 2 (HAS2) was downregulated in KLF7 knockdown cells. Based on TCGA database and immunoblotting assays, KLF7 positively regulated HAS2 in UCEC cells and tissues. Lastly, knockdown of HAS2 reversed the oncogenic role of KLF7 on UCEC cell proliferation, migration, and xenografted tumor development.

CONCLUSION

Taken together, we reveal that GNA14/KLF7/HAS2 signaling cascade exerts tumor promoting function during UCEC development.

Branch migration-based polymerase chain reaction combined with endonuclease IV-assisted target recycling probe/blocker system for detection of low-abundance point mutations

Sensitive detection of low-abundance point mutations in blood or tissue may provide a great opportunity for the minimally invasive diagnosis of cancer and other related diseases. We demonstrate a novel method for ultra-sensitive detection of point mutations at low abundance by combination of branch migration-based PCR with endonuclease IV-assisted target recycling probe/blocker system. The method is able to identify the point mutations at abundances down to 0.01-0.02%. We anticipate this method to be widely adopted in clinical diagnosis and molecular research.

Two-sided role of estrogen on endometrial carcinogenesis: stimulator or suppressor?

Endometrial carcinoma (EC) often expresses estrogen receptors (ER), and the growth of EC is stimulated by estrogen. Therefore, EC is considered to be an estrogen-dependent tumor. However, the role of estrogen in endometrial carcinogenesis is somewhat unclear because the majority of EC occurs at peri- or post menopause when serum estrogen levels are generally decreased. In this article, we describe the double-edged role of estrogen in the genesis of EC, especially in terms of mismatch repair functions in vitro and in vivo, i.e. when serum estradiol (E2) levels are relatively low (approximately less than 90 pg/ml), and E2 enhance the carcinogenesis, whereas high E2 levels may suppress the carcinogenesis. This will deepen mechanistic insight into unopposed estrogen.

Gene Promoter Methylation in Endometrial Carcinogenesis

Up to 60% of untreated atypical hyperplastic endometrium will develop into endometrial carcinoma (EC), and for those who underwent a hysterectomy a coexisting EC is found in up to 50%. Gene promoter methylation might be related to the EC development. The aim of this study is to determine changes in gene promoter profiles in normal endometrium, atypical hyperplasia (AH) and EC in relation to K-Ras mutations. A retrospective study was conducted in patients diagnosed with endometrial hyperplasia with and without subsequent EC. Promoter methylation of APC, hMLh1, O6-MGMT, P14, P16, RASSF1, RUNX3 was analysed on pre-operative biopsies, and correlated to the final histological diagnosis, and related to the presence of K-Ras mutations. In the study cohort (n=98), differences in promoter methylation were observed for hMLH1, O6-MGMT, and P16. Promoter methylation of hMLH1 and O6-MGMT gradually increased from histologically normal endometrium to AH to EC; 27.3, 36.4% and 38.0% for hMLH1 and 8.3%, 18.2% and 31.4% for O6-MGMT, respectively. P16 promoter methylation was significantly different in AH (7.7%) compared to EC (38%). K-Ras mutations were observed in 12.1% of AH, and in 19.6% of EC cases. No association of K-Ras mutation with promoter methylation of any of the tested genes was found. In conclusion, hMLH1 and O6-MGMT promoter methylation are frequently present in AH, and thus considered to be early events in the carcinogenesis of EC, whereas P16 promoter methylation was mainly present in EC, and not in precursor lesions supporting a late event in the carcinogenesis.

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.

Estrogen affects the negative feedback loop of PTENP1-miR200c to inhibit PTEN expression in the development of endometrioid endometrial carcinoma

Endometrial carcinoma is one of the most common malignancies in the female reproductive system. It is well-known that estrogen plays an important role in the pathogenesis of endometrioid endometrial carcinoma (EEC), and induces the cancer suppressor gene PTEN deletion. However, how estrogen affects PTEN expression remains unknown. In the present study, we found in 40 EEC specimens, miR-200c level was higher in most cancer areas than that in the adjacent normal endometrium, while PTEN and PTENP1 were lower. Moreover, the expression of PTEN/PTENP1 and miR-200c also showed a converse relationship in EEC cell lines. In addition, we demonstrated that miR-200c bound directly to PTEN and PTENP1, and PTENP1 could reverse miR-200c inhibition function to PTEN using a dual-luciferase reporter and RNA binding protein immunoprecipitation (RIP) assays. Next, 17β-estradiol (E2) treatment could improve miR-200c and drop the PTEN level, which caused a consequential increase of the phospho-PI3K-AKT pathway genes. When we stably knocked down estrogen receptor α (ERα) expression in the EEC cell line, the effects of E2 on miR-200c and PTEN declined. In addition, it was demonstrated that E2 might modulate cell proliferation, migration and invasion relying on the expression of miR-200c. Taken together, it can be concluded that estrogen improves the miR-200c level by combining with ER, PTENP1 and PTEN could be inhibited by miR-200c, and then activate the PI3K-AKT pathway. This work provided a new mechanism of EEC development and a new potential therapeutic target.

GNA14 silencing suppresses the proliferation of endometrial carcinoma cells through inducing apoptosis and G2/M cell cycle arrest

Endometrial carcinoma is the most common gynecological malignancy. The pathological factors triggering this disease are largely unknown. Although the role of guanine nucleotide-binding protein subunit α (GNA) 11 (GNA11) in melanoma has been described, the involvement of GNA14 in endometrial carcinoma remains to be determined. Here, we found that GNA14 expression was increased in endometrial carcinoma tissues compared with simple hyperplasia tissues. Based on lentivirus-mediated knockdown assay, we showed that GNA14 silencing significantly suppressed the proliferation of both HEC-1-A and Ishikawa cells. The caspase 3/caspase 7 activity and apoptosis were enhanced by GNA14 knockdown. GNA14 depletion led to cell cycle arrest at the G₂/M phase. In addition, Apoptosis Array analysis revealed that caspase-3 and Fas were up-regulated by GNA14 knockdown. Our study suggests that GNA14 silencing blunts endometrial carcinoma cell proliferation. Targetting GNA14 may bring help for the patients of endometrial carcinoma.

Immunohistochemical Detection of Hematopoietic Cell-specific Protein-Tyrosine Phosphatase (Tyrosine Phosphatase SHP-1) in a Series of Endometrioid and Serous Endometrial Carcinoma

In this study, we evaluated the expression of SHP-1 (PTPN6) in endometrioid (Ec) and serous (Sc) subtypes of endometrial carcinoma by immunohistochemical analysis. In total, 114 patients with Ec carcinoma and 48 patients with Sc carcinoma were enrolled in this study. The correlation between the type of histology, the grade of tumor, the stage of development, and immunoreactivity to SHP-1 was evaluated. Kaplan-Meier and multivariate survival analyses, using a Cox regression model, were performed to establish whether this marker has prognostic value in these malignancies, on the basis of follow-up and stratification of the patients according to their SHP-1 immunoreactivity. A significantly higher SHP-1 expression was observed in the Ec group compared with the Sc group (P=0.0005, Fisher exact test). In the Ec group, SHP-1 immunoreactivity was correlated with grading, demonstrating that more differentiated lesions expressed SHP-1 more frequently than less differentiated neoplasms (G1 vs. G2, P=0.0243, statistically significant value, Fisher exact test; G1 vs. G3, P=0.0088, extremely significant value, Fisher exact test). Instead, in the Sc group, SHP-1 expression was not correlated with grading, as Sc is now defined as a high-grade carcinoma. SHP-1 expression did not change with neoplastic progression in Ec and Sc groups. From both univariate and multivariate analysis in the Ec group, expression of SHP-1 remained a positive prognostic factor (P=0.004, log-rank test) [HR=0.32 (0.11 to 0.94), P=0.039]. In contrast, in the Sc group, no correlation between SHP-1 expression and survival was noted (P=0.77, log-rank test). In this study, we observed that the absence of SHP-1 in immunohistochemical analysis might serve as a marker of poor prognosis for a subset of high-grade endometrial cancer.

Mixed endometrial carcinomas with a "low-grade serous"-like component: a clinicopathologic, immunohistochemical, and molecular genetic study

Recently, we reported 2 mixed endometrioid endometrial carcinomas with a "low-grade serous"-like component, which does not fit into any of the 4 molecular groups described by The Cancer Genome Atlas. To understand the nature of these tumors, we have done an immunohistochemical and molecular genetic study of these 2 cases and added a third case. Immunoreactivity for p53, ER, Ki67, WT1, MLH1, PMS2, MSH2, and MSH6 was assessed. Targeted next-generation sequencing for somatic mutations, including genes commonly implicated in carcinogenesis including TP53, KRAS, and PIK3CA, and Sanger sequencing for PTEN and POLE were also performed. All patients were nulliparous and had morbid obesity. Their tumors showed a micropapillary component that resembled that of ovarian low-grade serous carcinoma and merged with villoglandular endometrioid carcinoma. The invasive tumor glands exhibited a microcystic, elongated, or fragmented pattern and contained psammoma bodies. Two tumors showed aberrant p53 expression, and all 3 were positive for ER. All showed KRAS mutations, and TP53 mutations were found in 2 cases. One patient developed peritoneal carcinomatosis, one patient is alive with disease, and another died of a brain tumor. The third patient, whose tumor was confined to the uterus (stage IA), is alive without evidence of disease, but she has been followed for only 6 months. Mixed endometrial carcinomas with a "low-grade" serous-like component exhibit a morphologic spectrum of endometrioid and serous differentiation with microcystic, elongated, or fragmented features; ER expression; KRAS and TP53 mutations; and aggressive behavior.

Molecular genetics and cellular events of K-Ras-driven tumorigenesis

Cellular transformation and the accumulation of genomic instability are the two key events required for tumorigenesis. K-Ras (Kirsten-rat sarcoma viral oncogene homolog) is a prominent oncogene that has been proven to drive tumorigenesis. K-Ras also modulates numerous genetic regulatory mechanisms and forms a large tumorigenesis network. In this review, we track the genetic aspects of K-Ras signaling networks and assemble the sequence of cellular events that constitute the tumorigenesis process, such as regulation of K-Ras expression (which is influenced by miRNA, small nucleolar RNA and lncRNA), activation of K-Ras (mutations), generation of reactive oxygen species (ROS), induction of DNA damage and apoptosis, induction of DNA damage repair pathways and ROS detoxification systems, cellular transformation after apoptosis by the blebbishield emergency program and the accumulation of genomic/chromosomal instability that leads to tumorigenesis.

[Histological and molecular classification of endometrial carcinoma and therapeutical implications]

Endometrial cancer is the fourth cause of cancer in women in France and is the second most common cancer of the gynecologic cancer after breast cancer with 7275 new cases in 2012. The incidence of this neoplasm tends to increase with population aging, diabetes and obesity's augmentation. In rare cases, a hereditary factor has been described: Lynch's syndrome. The therapeutic management of the patient depends on the endometrial biopsy which specifies the histological type and the histo-prognostic grade as well as the MRI which allow the tumor staging. Within the last decade, improvement in technologies such as genomic, transcriptomic and histological analyses, allowed the establishment of new and finer classifications of endometrial carcinomas. The latest classification proposed by The Cancer Genomic Atlas (TCGA), has been made routinely applicable through the international consortium TransPORTEC. It consists of 4 groups listed from good to poor prognosis: (1) ultra-mutated "POLE"; (2) hyper-mutated "MSI"; (3) low copy number "NSMP" and (4) high number of copies "TP53 mutated" (serous-like). This integrated characterization combined with mutational data opens new opportunities for therapeutic strategies.

Endometrial Carcinoma: Specific Targeted Pathways

Endometrial cancer (EC) is the most common gynecologic malignancy in the western world with more than 280,000 cases per year worldwide. Prognosis for EC at early stages, when primary surgical resection is the most common initial treatment, is excellent. Five-year survival rate is around 70 %.Several molecular alterations have been described in the different types of EC. They occur in genes involved in important signaling pathways. In this chapter, we will review the most relevant altered pathways in EC, including PI3K/AKT/mTOR, RAS-RAF-MEK-ERK, Tyrosine kinase, WNT/β-Catenin, cell cycle, and TGF-β signaling pathways. At the end of the chapter, the most significant clinical trials will be briefly discussed.This information is important to identify specific targets for therapy.

Molecular Pathology: Predictive, Prognostic, and Diagnostic Markers in Uterine Tumors

This article focuses on the diagnostic, prognostic, and predictive molecular biomarkers in uterine malignancies, in the context of morphologic diagnoses. The histologic classification of endometrial carcinomas is reviewed first, followed by the description and molecular classification of endometrial epithelial malignancies in the context of histologic classification. Taken together, the molecular and histologic classifications help clinicians to approach troublesome areas encountered in clinical practice and evaluate the utility of molecular alterations in the diagnosis and subclassification of endometrial carcinomas. Putative prognostic markers are reviewed. The use of molecular alterations and surrogate immunohistochemistry as prognostic and predictive markers is also discussed.

Mixed and Ambiguous Endometrial Carcinomas: A Heterogenous Group of Tumors With Different Clinicopathologic and Molecular Genetic Features

Besides endometrioid, serous, and clear cell carcinomas, there are endometrial carcinomas exhibiting mixed and ambiguous morphologic features. We have analyzed the immunophenotype (p53, p16, β-catenin, ER, HNF-1B, MLH1, and Ki-67) and mutational status (PTEN, KRAS, PIK3CA, and POLE) of 7 mixed carcinomas and 13 ambiguous carcinomas, all of them classified initially as mixed carcinomas. Only 2 of the 7 (28%) mixed carcinomas showed different immunophenotypes in different components. All but 2 tumors (5/7, 71%) overexpressed p53 and p16 and were negative for ER. Both carcinomas (2/7, 28%) showed a prominent micropapillary component that resembled an ovarian low-grade serous carcinoma and merged with villoglandular endometrioid carcinoma. The ambiguous carcinomas exhibited glandular architecture, high nuclear grade, and overlapping features of endometrioid and serous carcinomas. All tumors overexpressed p53 and p16, and the majority of cases (12/13, 92%) were negative for ER. KRAS mutations were identified in 3 of 7 (42%) mixed carcinomas, including the 2 cases with a "low-grade" serous-like component. PIK3CA mutations occurred in 2 (2/13, 15%) ambiguous carcinomas and PTEN mutations in 1 (1/7, 14%) mixed and 1 (1/13, 8%) ambiguous carcinoma. POLE exonuclease domain mutations were encountered in a case of mixed undifferentiated and well-differentiated (dedifferentiated) carcinoma. Two of the 7 (29%) mixed endometrial carcinomas and 5 of the 13 (38%) ambiguous carcinomas had extended beyond the pelvis (stages III and IV). Two of the 7 (29%) patients with mixed endometrial carcinoma and 6 of 12 (50%) patients with ambiguous endometrial carcinoma were alive with disease or had died of tumor. Our results show that, biologically, many so-called mixed carcinomas represent serous carcinomas with ambiguous morphology. Our series include 2 true mixed endometrial carcinomas with a "low-grade serous"-like component, microcystic, elongated, or fragmented features, KRAS mutations, and aggressive behavior.

Molecular profiles of benign and (pre)malignant endometrial lesions

Endometrial carcinomas are histologically classified as endometrioid, assumed to originate from hyperplastic endometrium, or non-endometrioid carcinomas, assumed to originate from atrophic endometrium. However, both on a histological and a molecular level there are indications that there are more carcinoma types and carcinogenetic pathways. This study aims to analyze endometrial carcinogenesis on a molecular level. The presence of known KRAS, PIK3CA, AKT1, CTNNB1, BRAF, EGFR and NRAS mutations was studied in proliferative, atrophic and hyperplastic endometrium, endometrioid and serous carcinomas, and the endometrium next to these carcinomas, using single molecule Molecular Inversion Probes. Mutations were found in 9 (15%) of the 62 non atypical, and in 6 (18%) of the 34 atypical hyperplasia cases. In comparison, mutations were found in 1 (3%) of the simple, and 8 (30%) of the 27 complex hyperplasia cases. In 12/22 (55%) endometrioid carcinomas, a mutation was found. The KRAS gene was most often mutated in carcinomas next to hyperplastic endometrium, whereas PIK3CA and CTNNB1 mutations were found in endometrioid carcinomas with adjacent atrophic endometrium. Complex hyperplasia rather than atypical hyperplasia appears to be the most important lesion in the carcinogenesis of endometrioid carcinomas, and KRAS, PIK3CA and CTNNB1 mutations appear to play an important role in this process. Carcinogenesis of endometrioid carcinomas next to hyperplasia seems to be different to that of those next to atrophia. The value of these findings in managing endometrial hyperplasia and carcinoma should be studied.

Targeted genomic profiling reveals recurrent KRAS mutations and gain of chromosome 1q in mesonephric carcinomas of the female genital tract

Mesonephric carcinoma is a rare form of gynecologic cancer derived from mesonephric remnants usually located in the lateral wall of the uterine cervix. An analogous tumor occurs in the adnexa, female adnexal tumor of probable Wolffian origin. The pathogenesis and molecular events in mesonephric carcinoma are not known. The aim of this study was to examine the molecular alterations in mesonephric carcinoma to identify driver mutations and therapeutically targetable mutations. This study consisted of 19 tumors from 17 patients: 18 mesonephric carcinomas (15 primary tumors and three metastatic tumors) and 1 female adnexal tumor of probable Wolffian origin. In two patients, both primary and metastatic tumors were available. Genomic DNA was isolated and targeted next-generation sequencing was performed to detect mutations, copy number variations, and structural variants by surveying full exonic regions of 300 cancer genes and 113 selected intronic regions across 35 genes. Fluorescence in situ hybridization (FISH) for 1p and 1q was performed in two cases. Eighty-one percent (13/16) of mesonephric carcinomas had either a KRAS (n=12) or NRAS (n=1) mutation. Mutations in chromatin remodeling genes (ARID1A, ARID1B, or SMARCA4) were present in 62% of mesonephric carcinomas. All mesonephric carcinomas lacked mutations in PIK3CA and PTEN. The most common copy number alteration was 1q gain, found in 12 (75%) mesonephric carcinomas; this was confirmed by FISH in two cases. Mesonephric carcinoma is characterized by molecular alterations that differ from those of more common variants of cervical and endometrial adenocarcinoma, which harbor KRAS/NRAS mutations in 7% and 25% of cases, respectively. KRAS/NRAS mutations are common in mesonephric carcinoma and are often accompanied by gain of 1q and mutations in chromatin remodeling genes. Targeting inhibitors of the RAS/MAPK pathway may be useful in the treatment of mesonephric carcinoma.

Modal variety of microsatellite instability in human endometrial carcinomas

PURPOSE

Microsatellite instability (MSI) in human endometrial cancer (EC) was analysed using a unique fluorescent technique. MSI is associated with various human neoplasms. However, the reported frequency of MSI differs widely in each malignancy. Methodological difficulties have in fact been pointed out in its assay techniques.

METHODS

We previously established a sensitive fluorescent technique in which the major methodological problems are overcome. Application of this technique has revealed two distinct modes of microsatellite alterations, i.e. Type A and Type B. In the present study, we have applied this technique to 94 ECs.

RESULTS

Significant microsatellite alterations were observed in 38 (40.4%) tumours of the panel. The two modes, Type A and Type B, were indeed observed in this malignancy. More importantly, we found that the modes more closely correlated with the molecular and clinicopathological backgrounds of the tumours than the established and widely used MSI grades, MSI-H and MSI-L. Type B MSI widely correlated with family history of hereditary non-polyposis colorectal cancer-associated cancers, whereas MSI-H only did with that of colorectal cancer. Furthermore, mutation in the KRAS oncogene, which has been regarded as generally infrequent in microsatellite-unstable tumours, was clearly associated with Type A MSI.

CONCLUSIONS

Our observations may suggest a biological relevance and a potential utility of the modal classification of MSI and, furthermore, added complexities to genomic instability underlying tumourigenesis in human endometrium.

Molecular mechanisms of tamoxifen-associated endometrial cancer (Review)

Tamoxifen has been prescribed to millions of females for breast cancer prevention or treatment. However, tamoxifen is known to significantly enhance the risk of developing endometrial lesions, including hyperplasia, polyps, carcinomas, and sarcoma. Notably, tamoxifen-associated endometrial cancer often has a poor clinical outcome. Understanding the molecular mechanism of tamoxifen-induced endometrial cancer is essential for developing strategies that minimize tamoxifen’s effects on the endometrium without jeopardizing its breast cancer treatment effects. However, this understanding remains limited. Tamoxifen appears to mediate its effect on endometrial cells through estrogenic and non-genomic pathways, rather than introducing a genomic alteration as a carcinogen. Although tamoxifen functions as an agonist and promotes cell proliferation in endometrial cancer, it also displays antagonist activity towards some estrogen targets. Alterations in estrogen receptor-α and its isoforms, as well as the membrane associated estrogen receptor G protein-coupled receptor 30, have been observed with tamoxifen-exposed endometrial cells, and likely mediate the effects of tamoxifen on endometrial cancer cell proliferation and invasion. In addition, gene profile studies of short-term exposure to tamoxifen indicate that the majority of tamoxifen targets are tamoxifen-specific. However, the tamoxifen regulated gene targets that are involved in mediating the effects of long-term exposure to tamoxifen are not yet fully understood. Recent progress has indicated a potential role of unfolded protein response and mammalian target of rapamycin signaling in tamoxifen-associated endometrial cancer. In the future, studies focusing on long-term effects of tamoxifen exposure are required to understand the molecular mechanisms of tamoxifen-associated endometrial cancer.

Ovarian and endometrial endometrioid adenocarcinomas have distinct profiles of microsatellite instability, PTEN expression, and ARID1A expression

AIMS

To understand the role of and differences in molecular alterations between endometrial and ovarian endometrioid adenocarcinomas.

METHODS AND RESULTS

We investigated the microsatellite status of 26 ovarian endometrioid adenocarcinomas (OVEMs), 42 endometrial endometrioid adenocarcinomas (EMCAs), and 19 concurrent (endometrial and ovarian) endometrioid adenocarcinomas. We evaluated the expression of the mismatch repair proteins, PTEN and ARID1A, and mutations of PTEN, KRAS, CTNNB1, and PIK3CA. High levels of microsatellite instability (MSI-H) were present in one of 26 OVEMs, 12 of 42 EMCAs, and four of 19 concurrent endometrioid adenocarcinomas. Only four of 19 concurrent endometrioid adenocarcinomas showed identical molecular alterations in their endometrial and ovarian components. Loss of ARID1A or loss of PTEN expression, and MSI-H, were more common in EMCAs than OVEMs (P = 0.044, P = 0.004, and P = 0.012, respectively). MSI-H in endometrial endometrioid adenocarcinomas was also related to loss of ARID1A expression (P < 0.001). In the cohort of MSI-H endometrioid adenocarcinomas involving the endometrium (n = 16), MSH6-deficient cases showed higher frequencies of CTNNB1 and PIK3CA mutations (P = 0.008 and P = 0.036, respectively), but lower frequencies of KRAS mutation (P = 0.011), than PMS2-deficient cases.

CONCLUSIONS

The different frequencies of molecular genetic alterations between endometrial endometrioid adenocarcinomas and ovarian endometrioid adenocarcinomas imply that distinct processes may be involved in their tumorigenesis or tumour progression.

Molecular alterations of PI3K/Akt/mTOR pathway: a therapeutic target in endometrial cancer

It is well established that the PI3K/Akt/mTOR pathway plays a central role in cell growth and proliferation. It has also been suggested that its deregulation is associated with cancer. Genetic alterations, involving components of this pathway, are often encountered in endometrial cancers. Understanding and identifying the rate-limiting steps of this pathway would be crucial for the development of novel therapies against endometrial cancer. This paper reviews alterations in the PI3K/Akt pathway, which could possibly contribute to the development of endometrial cancer. In addition, potential therapeutic targets of this pathway with emphasis on the mTOR inhibitors are also presented.

Histological features associated with occult lymph node metastasis in FIGO clinical stage I, grade I endometrioid carcinoma

AIMS

Lymph node involvement affects prognosis/treatment in endometrial carcinoma patients. We assessed various histological features associated with nodal metastasis in patients with grade I, stage I endometrial endometrioid carcinoma (EEC).

METHODS AND RESULTS

Eighteen stage I EECs with occult positive lymph nodes and 36 controls were assessed for depth of myoinvasion; microcystic, elongated and fragmented (MELF) pattern of myometrial invasion; lymphovascular invasion (LVI); and epithelial metaplasia. Nodal metastases were subclassified as isolated tumour cells (ITCs; ≤0.2 mm), micrometastasis (>0.2 mm and <2 mm), or macrometastasis (≥2 mm). Node-positive cases had significantly higher rates of LVI (P < 0.001) and MELF invasion (P = 0.003) on univariate analysis. Only LVI was associated significantly with nodal metastasis on multivariate analysis (P = 0.002). Tumours with MELF invasion demonstrated reduced E-cadherin expression. Macrometastases were identified in seven cases (39%) with or without micrometastasis/ITCs. Eight (44%) contained only ITCs. Eleven (61%) had histiocyte-like nodal metastases. Biopsy material from four of six (67%) and five of 17 (29%) cases with and without nodal metastasis showed detached eosinophilic tumour cell buds. Of the former, three were associated with histiocyte-like nodal metastases - a feature absent in biopsies without tumour budding.

CONCLUSIONS

Lymph nodes from grade I EEC exhibiting cellular budding or LVI should be examined for occult metastases, especially in the form of histiocyte-like cells.

Molecular pathology of endometrial carcinoma

This review paper discusses the main molecular alterations of endometrial carcinoma, the most common cancer of the female genital tract. Two clinicopathological variants are recognized: the oestrogen-related (type I, endometrioid carcinoma) and the non-oestrogen-related (type II, non-endometrioid carcinoma). Whereas type I shows microsatellite instability and mutations in PTEN, PIK3CA, K-RAS and CTNNB1 (beta-catenin), type II exhibits TP53 mutations and chromosomal instability. Recent investigations regarding the role of non-coding RNA have provided important information regarding tumour progression. Understanding pathogenesis at the molecular level is essential for identifying biomarkers of potential use in targeted therapies.

Genetic alterations in SMAD4 and K-ras in Serbian patients with endometrial carcinoma

OBJECTIVE

This study was aimed at analyzing alterations in K-ras gene and SMAD4 gene promoter in endometrial carcinoma tissue in Serbian patients.

METHODS/MATERIALS

The study has encompassed 36 patients whose endometrial cancer tissue samples and peripheral blood samples were analyzed for the presence of alterations in the K-ras gene and the SMAD4 gene promoter. The detection of K-ras codon 12 mutation was performed by polymerase chain reaction restriction fragment length polymorphism technique. Analysis of mononucleotide repeat variants at -462T(15) and -4T(12) of the SMAD4 gene promoter was performed by capillary electrophoresis analysis of DNA fragments fluorescently labeled by polymerase chain reaction.

RESULTS

Mutation in codon 12 of the K-ras gene was detected with relatively high frequency of 75.0% (27 of 36 cases). Analysis of 2 mononucleotide repeats in the SMAD4 gene promoter showed that in most cases, haplotypes -462T(15)/-4T(12) and -462T(16)/-4T(12) were present; whereas in one case, a novel haplotype -462T(15)/-4T(10) was detected.

CONCLUSIONS

Findings on the role and potential significance of the K-ras codon 12 mutation and SMAD4 gene promoter variants in patients with endometrial carcinoma remain controversial, and their occurrence in this type of cancer should be further investigated.

Endometrial carcinoma: molecular alterations involved in tumor development and progression

In the western world, endometrial carcinoma (EC) is the most common cancer of the female genital tract. The annual incidence has been estimated at 10-20 per 100,000 women. Two clinicopathological variants are recognized: the estrogen related (type I, endometrioid) and the non-estrogen related (type II, non-endometrioid).The clinicopathological differences are paralleled by specific genetic alterations, with type I showing microsatellite instability and mutations in phosphatase and tensin homologue deleted on chromosome 10, PIK3CA, K-RAS and CTNNB1 (β-catenin), and type II exhibiting TP53 mutations and chromosomal instability. Some non-endometrioid carcinomas probably arise from pre-existing endometrioid carcinomas as a result of tumor progression and, not surprisingly, some tumors exhibit combined or mixed features at the clinical, pathological and molecular levels. In EC, apoptosis resistance may have a role in tumor progression. Understanding pathogenesis at the molecular level is essential in identifying biomarkers for successful targeted therapies. In this review, the genetic changes of endometrial carcinogenesis are discussed in the light of the morphological features of the tumors and their precursors.

FGFR2 alterations in endometrial carcinoma

Fibroblast growth factor receptor 2 (FGFR2) is a tyrosine kinase receptor involved in many biological processes such as embryogenesis, adult tissue homeostasis and cell proliferation. Mutations in FGFR2 have been reported in up to 10-12% of endometrial carcinomas identical to those found in congenital craniofacial disorders. Inhibition of FGFR2 could be a new therapeutic target in endometrial carcinoma. FGFR2 immunostaining was assessed in three tissue microarrays: one constructed from paraffin-embedded blocks of 60 samples of normal endometrium in different phases of menstrual cycle, and two tissue microarrays containing endometrial carcinoma samples (95 and 62 cases). FGFR2 expression was correlated with stage, histological type and grade as well as with immunostaining of PTEN, RASSF1A, estrogen and progesterone receptors, KI67, Cyclin D1, STAT-3 and SPRY2. FGFR2 mutations were assessed by PCR and direct sequencing, with DNA obtained from 31 paraffin-embedded endometrial carcinoma samples. In normal endometrium, FGFR2 expression was higher in the secretory than in the proliferative phase (P=0.001), with an inverse correlation with Ki67 (P=0.00032), suggesting a tumor-suppressor role for FGFR2 in normal endometrium. Cytoplasmic expression of FGFR2 was higher in endometrial carcinoma when compared with the atrophic endometrium from the same patients (P=0.0283), but was lower in comparison with normal endometrium from women in the menstrual cycle. Interestingly, nuclear staining was observed in some cases, and it was less frequent in endometrial carcinoma when compared with the adjacent atrophic endometrium (P=0.0465). There were no statistical differences when comparing superficial and myoinvasive endometrial carcinoma samples. Endometrioid endometrial carcinomas showed higher expression of FGFR2 than nonendometrioid endometrial carcinomas (fold change 2.56; P=0.0015). Grade III endometrioid endometrial carcinomas showed decreased FGFR2 expression when compared with grade II endometrioid endometrial carcinomas (P=0.0055). No differences were found regarding pathological stage. Two missense mutations of FGFR2 gene were detected in exons 6 and 11 (S252W and N549K, respectively; 6.45%). Results support the hypothesis that FGFR2 has a dual role in the endometrium, by inhibiting cell proliferation in normal endometrium during the menstrual cycle, but acting as an oncogene in endometrial carcinoma.

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.

KSR1 is overexpressed in endometrial carcinoma and regulates proliferation and TRAIL-induced apoptosis by modulating FLIP levels

The Raf/MEK/extracellular signal-regulated kinase (ERK) pathway participates in many processes altered in development and progression of cancer in human beings such as proliferation, transformation, differentiation, and apoptosis. Kinase suppressor of Ras 1 (KSR1) can interact with various kinases of the Raf/MEK/extracellular signal-regulated kinase pathway to enhance its activation. The role of KSR1 in endometrial carcinogenesis was investigated. cDNA and tissue microarrays demonstrated that expression of KSR1 was up-regulated in endometrial carcinoma. Furthermore, inhibition of KSR1 expression by specific small hairpin RNA resulted in reduction of both proliferation and anchorage-independent cell growth properties of endometrial cancer cells. Because inhibition of apoptosis has a pivotal role in endometrial carcinogenesis, the effects of KSR1 in regulation of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis were investigated. KSR1 knock-down sensitized resistant endometrial cell lines to both TRAIL- and Fas-induced apoptosis. Sensitization to TRAIL and agonistic anti-Fas antibody was caused by down-regulation of FLIP (FLICE-inhibitory protein). Also investigated was the molecular mechanism by which KSR1 regulates FLIP protein levels. It was demonstrated that KSR1 small hairpin RNA did not affect FLIP transcription or degradation. Rather, FLIP down-regulation was caused by Fas-associated death domain protein-dependent inhibition of FLIP translation triggered after TRAIL stimulation in KSR1-silenced cells. Re-expression of heterologous KSR1 in cells with down-regulated endogenous KSR1 restored FLIP protein levels and TRAIL resistance. In conclusion, KSR1 regulates endometrial sensitivity to TRAIL by regulating FLIP levels.

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.

Endocervical-like (Müllerian) mucinous borderline tumours of the ovary are frequently associated with the KRAS mutation

AIMS

  Clinicopathological aspects of the endocervical-like mucinous borderline tumour of the ovary (EMBT), including higher frequencies of bilaterality, endometriosis and hormone receptor reactivity, and often admixtures of various Müllerian-type epithelia, closely resembles endometrioid tumour more than mucinous borderline tumour of the intestinal type (IMBT). Thus, the aims of this study were to determine whether EMBT is really a subtype of mucinous borderline tumours, as shown in the current classification system, and to determine the best classification for EMBT.

METHODS AND RESULTS

  The clinicopathological and immunohistochemical features of 17 EMBTs were analysed, including oestrogen receptor (ER), progesterone receptor (PR), PTEN, cytokeratins (CK) 7 and 20, and β-catenin. Additionally, mutational analyses of the KRAS (exon 1) and PTEN genes (all nine exons) were performed in all cases, and the results were compared with literature findings for IMBT and endometrioid tumours. Twelve patients (71%) were confirmed histologically to have endometriosis in one or both ovaries. In seven cases, gradual transitions from endometriotic foci to the EMBT were identified. Immunohistochemically, all cases were reactive for ER and PR, with no nuclear expression of β-catenin. CK7 positivity was strong in all patients, whereas there was no reactivity for CK20. PTEN reactivity was diffuse in the nuclei of epithelial and underlying stromal cells. Sixty-nine per cent showed KRAS mutations in exon 1 and codon 12, but no PTEN mutation was identified in any of the nine exons.

CONCLUSION

  Our study suggests that EMBT has features of both mucinous and endometrioid tumours and is an additional tumour type arising in endometriosis. While clinicopathological features of EMBTs are closer to endometrioid tumours, they still have molecular characteristics closer to IMBTs.

Immunoglobulin G fragment C receptor polymorphisms and KRAS mutations: are they useful biomarkers of clinical outcome in advanced colorectal cancer treated with anti-EGFR-based therapy?

KRAS mutations have been identified as a strong predictor of resistance to anti-epidermal growth factor receptor (EGFR) therapies. Besides inhibiting the EGFR pathway, anti-EGFR monoclonal antibodies may exert antitumor effects through antibody-dependent cell-mediated cytotoxicity (ADCC). Through this mechanism, the antibody fragment C portion (Fcγ) interacts with Fc receptors (FcγRs) expressed by immune effectors cells. We investigated the association of FcγR polymorphisms and KRAS mutation with the clinical outcome of 104 refractory metastatic colorectal cancer (mCRC) patients treated with anti-EGFR antibodies. FcγRIIa-H131R and FcγRIIIa-V158F polymorphisms were analyzed in genomic DNA using a 48.48 dynamic array on the BioMark system (Fluidigm, South Sanfrancisco, CA, USA). Tumor tissues from 96 cases were screened for KRAS mutations. KRAS mutation was associated with a lower response rate (RR) (P = 0.035) and a shorter progression-free survival (PFS) (3 vs 7 months; P = 0.36). FcγRIIa-H131R and FcγRIIIa-V158F polymorphisms did not show statistically significant associations with response, PFS, or KRAS status. In the logistic regression analysis, KRAS status (P = 0.04) and skin toxicity (P = 0.03) were associated with RR. By multivariate analysis, the clinical risk classification (P = 0.006) and skin toxicity (P < 0.0001) were found to be independent risk factors for PFS. In conclusion, the FcγRIIa and FcγRIIIa polymorphisms are not useful as molecular markers for clinical outcome in mCRC patients. To date, the EORTC (European Organization for Research and Treatment of Cancer Classification), skin toxicity, and KRAS status are the only reliable biomarkers to identify patients that would benefit from anti-EGFR therapy.

Controversies in the management of endometrial carcinoma

Endometrial carcinoma is the most common type of female genital tract malignancy. Although endometrial carcinoma is a low grade curable malignancy, the condition of the disease can range from excellent prognosis with high curability to aggressive disease with poor outcome. During the last 10 years many researches have provided some new valuable data of optimal treatments for endometrial carcinoma. Progression in diagnostic imaging, radiation delivery systems, and systemic therapies potentially can improve outcomes while minimizing morbidity. Firstly, total hysterectomy and bilateral salphingo-oophorectomy is the primary operative procedure. Pelvic lymhadenectomy is performed in most centers on therapeutic and prognostic grounds and to individualize adjuvant treatment. Women with endometrial carcinoma can be readily segregated intraoperatively into “low-risk” and “high-risk” groups to better identify those women who will most likely benefit from thorough lymphadenectomy. Secondly, adjuvant therapies have been proposed for women with endometrial carcinoma postoperatively. Postoperative irradiation is used to reduce pelvic and vaginal recurrences in high risk cases. Chemotherapy is emerging as an important treatment modality in advanced endometrial carcinoma. Meanwhile the availability of new hormonal and biological agents presents new opportunities for therapy.

Expression profiling of 22 genes involved in the PI3K-AKT pathway identifies two subgroups of high-grade endometrial carcinomas with different molecular alterations

Previously, we showed that PIK3CA and p53 alterations in uterine endometrial carcinomas correlate with poor prognosis. However, the contribution of phosphatidylinositol 3-kinase (PI3K) -AKT deregulation to endometrial carcinogenesis is not completely understood. The purpose of this study was to analyze alterations of this pathway in endometrial carcinomas and correlate them with the most common genetic abnormalities. Expression profiling of 22 genes involved in PI3K-AKT signaling pathway was analyzed in 38 endometrial carcinomas using TaqMan low-density array (TLDA) analysis. The gene expression pattern was analyzed by hierarchical clustering analysis. Unsupervised clustering divided the high-grade endometrial carcinomas into two clusters. One cluster identified tumors with alterations in the PI3K-AKT signaling pathway (exon 20 PIK3CA mutations and/or PTEN mutations 9/15; 60%), and p16 protein overexpression (8/13; 62%). Almost all non-endometrioid adenocarcinomas (serous and clear cell adenocarcinomas) were segregated into this cluster. In contrast, the other cluster identified tumors with p53 alterations (6/6; 100%), p16 protein overexpression (5/5; 100%), and exon 9 PIK3CA mutations (2/6; 33%). Exon 20 PIK3CA and PTEN mutations were not found in this subgroup. Low-grade endometrial carcinomas clustered in a third subgroup characterized by high frequency of PTEN mutations (10/17; 59%) and microsatellite instability (6/17; 35%). Our results show that gene expression profile differences in the PI3K-AKT signaling pathway identify two subgroups of high-grade endometrial carcinomas with different molecular alterations (PI3K-AKT pathway vs p53 alterations) that may have distinct roles in endometrial carcinogenesis. Identification of these subgroups can provide insight into the biology of these tumors and may facilitate the development of future treatments.

DcR1 expression in endometrial carcinomas

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a member of the TNF family, which mediates apoptosis by the extrinsic pathway. Up-regulation of decoy receptors, DcR1 and DcR2, may result in diminished binding of TRAIL to their functional receptors. DcR1 expression was assessed in normal endometrial tissue (NE) and endometrial carcinoma (EC) samples by immunohistochemistry (IHC) and quantitative real-time polymerase chain reaction (PCR). IHC was performed in two tissue microarrays; one composed of 80 samples of NE and a second one constructed from paraffin-embedded blocks of 62 EC. For quantitative real-time RT-PCR analysis, RNA was obtained from 19 NE and 28 EC samples using Trizol. mRNA expression of DcR1 was assessed with Taqman-based assays in an Abi-Prism 700 SDS. Results were correlated with stage, histological type, and grade. By IHC, cytoplasmic expression of DcR1 was frequently seen in NE (79.6%) and varied according to the menstrual cycle. Positive DcR1 immunostaining was also detected in EC (98.1% of the cases) without any specific statistical association with histological type, grade, and stage. By quantitative real-time PCR, all NE had similar levels of DcR1expression (0.8-1.7 RQ), which were considered the basal levels of DcR1 expression in NE. Increased DcR1 expression (> or =5-fold higher than the basal levels) was detected in 13 of 28 EC (46.4%). High DcR1 expression levels were found in ECs of different stages: IA, four of 12 (33%); IB, two of four (50%); IC, four of six (66%); and IIA and IIB three of six (50%). Results suggest that DcR1 expression occurs in a subset of EC and may contribute to resistance to TRAIL-induced apoptosis.

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.

Identification of potential serum markers for endometrial cancer using protein expression profiling

OBJECTIVES

Screening method of endometrial cancer (EC) has not been established yet. Our study was to explore serum biomarkers of EC patients using surface-enhanced laser desorption and ionization-time-of-flight mass spectrometry (SELDI-TOF MS).

METHODS

Serum samples from 65 EC patients and 40 controls were analyzed by SELDI-TOF MS (training set). Single- and multi-variant analyses were performed to compare protein profiles in serum of EC patients and healthy controls. Subsequently, blind test set including 40 EC patients and 40 controls were analyzed for validation.

RESULTS

A panel of four biomarker candidates were selected in training set analysis. These markers could also distinguish stage I patients from controls. Among them, two biomarkers were purified and identified as apolipoprotein A1 and a modified form of apolipoprotein C1. Screening for blind test set using dual-biomarker analysis yielded a sensitivity of 82% and a specificity of 86%.

CONCLUSIONS

Involvement of apolipoproteins with EC is first suggested in this study. In addition to possibility of screening method for EC, findings of these new biomarkers might be related with carcinogenesis or predisposition to EC.

Monitoring of Endometrial K-ras Mutation in Tamoxifen-Treated Patients With Breast Cancer

Introduction:

A high incidence of endometrial K-ras mutations has been reported in tamoxifen (TAM)-treated patients with breast cancer. We examined the changes in the frequency of the endometrial K-ras mutations after the cessation of TAM treatment.

Methods:

DNA was extracted from fresh cytological or polypectomy samples of the endometrium in 28 patients who had undergone TAM treatment of breast cancer. Mutations were detected by an enriched polymerase chain reaction-enzyme-linked minisequence assay (Sumitomo Metal Industry, Inc, Tokyo, Japan). K-ras codon 12 mutations were monitored in these 28 patients.

Results:

An initial examination detected endometrial K-ras mutations in 13 of the 28 patients. However, repeated examinations performed after cessation of TAM treatment did not detect endometrial K-ras mutations in any of these 13 patients. No endometrial K-ras mutation has been detected in the repeated examinations performed for these patients for more than 2 years since the cessation of TAM treatment. In addition, the 15 patients who did not have endometrial K-ras mutations in the initial examination did not demonstrate them in repeat examinations.

Conclusions:

The cessation of TAM treatment may reduce the risk of developing endometrial cancers through K-ras mutations.

Transitional cell tumors of the ovary: a comparative clinicopathologic, immunohistochemical, and molecular genetic analysis of Brenner tumors and transitional cell carcinomas

Transitional cell tumors of the ovary include 2 distinct clinicopathologic categories: Brenner tumors and transitional cell carcinomas (TCCs). Their molecular genetic alterations have not been fully investigated. We have performed a clinicopathologic, immunohistochemical, and molecular genetic analysis of 19 transitional cell tumors including 13 Brenner tumors (5 benign, 7 borderline, and 1 malignant) and 6 TCCs. Immunoreactivity for epidermal growth factor receptor (EGFR), Ras, Cyclin D1, p16, Rb, and p53, as well as fluorescence in situ hybridization analysis for EGFR were assessed in all cases. Screening for mutations in K-Ras, B-Raf, CTNNB1, PIK3CA, and p53 genes was also performed. The mean patient age was 58 years (range, 32 to 85 y). Abdominal enlargement and pain were the usual complaints. Treatment was known in 14 patients: 10 had hysterectomy with bilateral salpingo-oophorectomy, which was accompanied by omentectomy in 7; and 4 had only unilateral or bilateral salpingo-oophorectomy, 1 with omentectomy. Four patients had brachytherapy. Six borderline Brenner tumors were stage IA and 1 stage IIA. The malignant Brenner tumor was stage IA. One TCC was stage IA, one IC, 2 IIIC and the stage was unknown in 2 cases. Follow-up information was available only in 5 of the nonbenign cases. Two patients who had borderline Brenner tumors were alive and well at 3 and 10.9 years. The patient who had a malignant Brenner tumor died of pulmonary thromboembolism shortly postoperatively, and 2 patients with TCCs died of tumor 1.8 and 13 years, postoperatively. Brenner tumors and TCCs differed mainly in the expression of EGFR, p16, and p53. Benign Brenner tumors showed a low immunoexpression for all markers. Borderline Brenner tumors failed to immunoreact for p16, Rb, and p53; and showed weak immunostaining for Cyclin D1, moderate for Ras, and strong for EGFR. The malignant Brenner tumor was also negative for p16, Rb, and p53, and strongly positive for Cyclin D1, Ras, and EGFR. In contrast, TCCs had p53 mutations with p53 and p16 protein overexpression and showed a negative immunoreaction for EGFR, Cyclin D1, and Ras. Our results suggest that Brenner tumors and TCCs follow different tumorigenic pathways, whereas borderline and malignant Brenner tumors are low-grade neoplasms with activation of the PI3K/AKT pathway through EGFR, TCCs are high-grade tumors that have p53 mutations and p16 and p53 protein overexpression.

Concomitant PI3K-AKT and p53 alterations in endometrial carcinomas are associated with poor prognosis

The status of p53 and the phosphatidylinositol 3-kinase-AKT (PI3K-AKT) signaling pathway was investigated in 132 endometrial carcinomas, including endometrioid endometrial carcinomas, non-endometrioid endometrial carcinomas, and mixed endometrioid adenocarcinomas-non-endometrioid adenocarcinomas. Results were compared with the clinicopathologic parameters associated with prognosis, patients' follow-up, and other genetic alterations found frequently in these tumors. Molecular genetic differences between low-grade and high-grade endometrioid adenocarcinomas were encountered; ie, PIK3CA mutations were detected in 26 and 34% of cases, respectively. We found p53 alterations in only 17% of high-grade endometrioid adenocarcinomas. In contrast, non-endometrioid adenocarcinomas had a higher frequency of p53 alterations (54%), PIK3CA mRNA overexpression (45%), and exon 20 PIK3CA mutations (21%). In the mixed endometrioid adenocarcinomas-non-endometrioid adenocarcinomas, the most frequent alterations were p53 (50%) and PIK3CA (44%) mutations, followed by PTEN mutations (38%). In some cases, p53 and PIK3CA alterations coexisted, but they rarely coexisted with the PTEN mutations. Our findings suggest that the PIK3CA mutations are frequent events in endometrial carcinomas of any histological type. However, location of the PIK3CA mutations, either in exon 9 or exon 20, varies significantly according to the histologic grade and type of carcinoma. Carcinomas with exon 20 PIK3CA mutations or PIK3CA mRNA overexpression were often high-grade carcinomas associated with myometrial invasion; in contrast, tumors that carried exon 9 mutations were more likely to be low-grade carcinomas. The Kaplan-Meier analysis suggested that p53 alterations (strong immunoexpression or mutations) conferred a worse prognosis (P=0.000). Although alterations in the PI3K-AKT signaling pathway alone did not influence overall survival, patients with deregulated PI3K-AKT pathway (PIK3CA and/or PTEN alterations) and p53 alterations had shorter survival (P=0.000) than patients with only p53 alterations. Such a relationship was lost when we considered exon 9 PIK3CA mutations. Our results contribute to further characterize the molecular genetic model for endometrial carcinogenesis.

Endometrial hyperplasia and the risk of progression to carcinoma

The primary presenting symptom of endometrial neoplasia is abnormal uterine bleeding, which typically prompts an endometrial biopsy to rule out carcinoma. Approximately 70% of women with abnormal uterine bleeding are diagnosed with benign findings and 15% are diagnosed with carcinoma. The remaining 15% receive a diagnosis of endometrial hyperplasia (EH), which includes a broad range of lesions, from mild, reversible proliferations to the immediate precursors of carcinoma. The widely used World Health Organization (WHO) system classifies EH according to four combinations of glandular crowding and nuclear atypia: simple (SH), complex (CH), simple atypical (SAH), or complex atypical hyperplasia (CAH), although the two forms of atypical hyperplasia (AH) are often collapsed into one category. Diagnoses of EH raise three issues. First, the low interobserver reproducibility-less than 50% in almost all studies-hinders the ability of WHO-based classification to effectively guide clinical management. Second, approximately 50% of women diagnosed with AH have concurrent carcinoma. Not surprisingly, most women with AH undergo hysterectomy as primary treatment, but non-surgical management can be effective. Third, data on progression risks for women with EH who retain their uterus are extremely limited. Emerging data indicate the long-term risk among women with SH or CH is less than 5%, but the risk among women with AH is approximately 30%. These data highlight priority areas for future research, such as increasing the diagnostic reproducibility of EH, improving the discrimination between AH and carcinoma, and identifying biomarkers to stratify risks or serve as indicators of response to clinical treatment.