Theories of endometrial carcinogenesis: a multidisciplinary approach

Body size in relation to cancer of the uterine corpus in 1 million Norwegian women

A positive association between overweight/obesity and endometrial cancer has been observed. It has been hypothesized that obesity is mostly associated with a subtype described as estrogen-dependent (Type I tumors), constituting about 80% of the endometrial tumors. Few epidemiologic studies have, however, analyzed different histological subtypes separately. The present study aimed at exploring the relations between body size and histological subtypes of cancer of the uterine corpus. Height and weight were measured in over 1 million Norwegian women aged 20-74 during 1963-2001. During follow-up, 9,227 cancers of the uterine corpus were diagnosed. The tumors were classified as Type I tumors (mostly endometrial adenocarcinomas with subgroups), Type II tumors (papillary, serous, and clear cell adenocarcinomas and some poorly differentiated carcinomas), sarcomas, and mixed tumors. Relative risks (RRs) of cancer of the uterine corpus were estimated using Cox proportional hazards regression. Compared with women with normal BMI, overweight and obese women had an overall RR of cancer of the uterine corpus of 1.36 (95% CI: 1.29-1.42) and 2.51 (95% CI: 2.83-2.66). The increase in risk was most pronounced for Type I tumors, but was also seen for Type II tumors, sarcomas and mixed tumors. The overall RR of corpus uteri cancer associated with a 10-cm increase in height was 1.09 (95% CI: 1.05-1.13), and was mostly observed for Type I tumors.

Pathologic features of endometrial carcinoma associated with HNPCC

BACKGROUND

Endometrial carcinoma is a common malignancy in hereditary nonpolyposis colorectal carcinoma (HNPCC). Like colon carcinoma, endometrial carcinoma is diagnosed at an earlier age in women with HNPCC. In contrast to colon carcinoma, the pathologic features of endometrial carcinoma in HNPCC have not been studied in detail. It was the purpose of this study to pathologically characterize a series of HNPCC associated endometrial carcinomas.

METHODS

Fifty women with HNPCC and endometrial carcinoma were analyzed from four different hereditary cancer registries. H&E stained slides and pathology reports were reviewed for clinically important pathologic features of endometrial carcinoma. These results were compared with those for two different groups of sporadic endometrial carcinoma--women younger than age 50 years (n = 42) and women of all ages with tumors demonstrating microsatellite instability (MSI-high) secondary to methylation of MLH1 (n = 26).

RESULTS

Nearly one-fourth of HNPCC patients in this study had endometrial tumors with pathologic features that would require adjuvant therapy after hysterectomy. There was a trend toward the HNPCC patients having more nonendometrioid tumors; all of these patients were carriers of MSH2 mutations. Such nonendometrioid tumors were extremely rare in the MLH1 methylated group. A subset of MLH1 methylated sporadic tumors demonstrated a unique, 'undifferentiated' histology that was not observed in HNPCC or the young group.

CONCLUSION

Data suggest a genotype-phenotype relation in which microsatellite instability resulting from MLH1 methylation is almost exclusively associated with classical or 'undifferentiated' endometrioid tumors, whereas microsatellite instability secondary to MSH2 mutation can result in a more variable histologic spectrum of endometrial carcinoma.

Allelic loss at TP53 is not related to p53 protein overexpression in primary human endometrial carcinomas

We examined loss of heterozygosity (LOH) at the TP53 gene in primary human endometrial carcinomas (EC), and investigated the relationship between allelic loss, p53 protein overexpression, pRb-1 pathway alterations and MIB-1 proliferative activity. Applying the non-isotopic PCR-RFLP/VNTR-silver staining techniques, we investigated TP53 LOH in 46 tumors at four polymorphic loci. Out of 42 informative carcinomas, LOH was found in 19% of the cases studied. In general, there was no significant relationship between LOH and the clinical and pathological variables of cancer, including patient age, clinical stage, histological grade or depth of myometrial invasion. Interestingly, none of 7 tumors associated with hyperplasia revealed allelic imbalance, whereas 8 of 27 (30%) tumors without hyperplasia exhibited LOH (p=0.312; Fisher's exact test). Overexpression of nuclear p53 was not correlated with allelic loss at TP53 (p=0.336, Fisher's exact test). It is worth pointing out that p53 immunoreactivity was significantly related to proliferative activity of cancer (R=0.42, p=0.0037; Spearman's rank correlation test). A tendency towards a poorer outcome was reported in EC patients displaying TP53 LOH during short-time follow-up (p=0.093; log-rank test). None of the tumors simultaneously showed LOH at TP53 and RB1 genes (R=-0.211, p=0.16; Spearman's rank correlation test). p16INK4A alterations (LOH and gene deletion) occurred concomitantly, with 3 tumors showing the TP53 allelic loss, whereas the cyclin D1/cdk4 complex was overexpressed in a case with TP53 LOH. Altogether, losses at TP53 were not associated with p53 nuclear overexpression, but may affect a subset of EC patients characterized by an unfavorable prognosis at short-time follow-up. Allelic loss at TP53 seems to arise independently of LOH at the RB1 gene in carcinomas of the uterine corpus in humans. Disruptions at p16INK4A and/or cdk4/cyclin D1 concomitantly occurring with TP53 LOH may participate in the development of a subset of endometrioid-type ECs.

The association between p53 expression, stage and histological features in endometrial cancer

OBJECTIVE

Alterations of the p53 gene have been widely suggested to be relevant to the development of endometrial carcinoma. However, contradictory results have been reported when immunohistochemical determination of p53 expression has been correlated with stage and histological features of the tumours.

STUDY DESIGN

Pathology findings were reviewed and p53 immunoperoxidase staining was performed in 240 cases of endometrial carcinoma.

RESULTS

Uterine papillary serous adenocarcinomas showed significantly higher p53 overexpression than uterine endometrioid adenocarcinomas (100.0% versus 61.0%, p<0.005). p53 overexpression was significantly higher in the secretory variant (85.7%) than in the typical endometrioid carcinoma (60.0%) (p<0.05). p53 expression did not differ between early (stage I) and advanced (stage II-IV) carcinomas. Likewise, no difference was observed in p53 expression among different architectural grades. The incidence of metastasis to lymph nodes was similar in p53 positive (13.7%) and in p53 negative tumours (12.5%).

CONCLUSION

In the present series, p53 immunostaining did not differ between cases with different FIGO stages or histologic characteristics of the tumours. No simple relationship exists between the immunohistochemical determination of p53 expression and the biological aggressiveness of endometrial carcinomas.

Progression of conservatively treated endometrial carcinoma after full term pregnancy: A case report

INTRODUCTION

We describe a case of conservatively treated endometrial endometrioid (EE) adenocarcinoma which showed an aggressive clinical outcome after pregnancy.

CASE

A 30-year-old woman with a well differentiated EE adenocarcinoma decided to attempt a conservative approach and underwent progestin treatment with subsequent negative ultrasound and hysteroscopic controls. After 3 months, she conceived and at 36 weeks of gestation, a cesarean section was performed with multiple negative biopsies. Eight 8 months after delivery, an exploratory laparotomy documented disseminated poorly differentiated EE adenocarcinoma. Staging work up revealed diffuse metastatic disease. Despite chemotherapy, the patient experienced progression of disease with fatal acute respiratory syndrome due to massive neoplastic pulmonary lymphangitis.

CONCLUSION

Conservative medical management of endometrial cancer in young women willing to preserve their reproductive potential, carries on potential risks. Careful selection of cases, informed consent, and strict follow up procedures are mandatory.

Gene expression profiles of serous, endometrioid, and clear cell subtypes of ovarian and endometrial cancer

PURPOSE

The presence of similar histologic subtypes of epithelial ovarian and endometrial cancers has long been noted, although the relevance of this finding to pathogenesis and clinical management is unclear. Despite similar clinical characteristics, histologic subtypes of cancers of the ovary and endometrium are treated according to organ of origin. This study compares the gene expression profiles of analogous histologic subtypes of cancers of the ovary and endometrium using the same genomic platform to determine the similarities and differences between these tumors.

EXPERIMENTAL DESIGN

Gene expression profiles of 75 cancers (endometrioid, serous, and clear cell) of the ovary and endometrium, five renal clear cell cancers, and seven normal epithelial brushings were determined using a 11,000-element cDNA array. All images were analyzed using BRB ArrayTools. Validation was done using real-time PCR on select genes and immunohistochemical staining.

RESULTS

Comparison across endometrial and ovarian cancers and serous and endometrioid tumors showed expression patterns reflecting their organ of origin. Clear cell tumors, however, showed remarkably similar expression patterns regardless of their origin, even when compared with renal clear cell samples. A set of 43 genes was common to comparisons of each of the three histologic subtypes of ovarian cancer with normal ovarian surface epithelium.

CONCLUSIONS

The comparison of the gene expression profiles of endometrioid and serous subtypes of ovarian and endometrial cancer are largely unique to the combination of a particular subtype in a specific organ. In contrast, clear cell cancers show a remarkable similarity in gene expression profiles across organs (including kidney) and could not be statistically distinguished.

Determination of HER2/neu status in uterine serous papillary carcinoma: Comparative analysis of immunohistochemistry and fluorescence in situ hybridization

OBJECTIVE

To evaluate and compare HER2/neu protein overexpression and gene amplification in uterine serous papillary endometrial cancer (USPC).

STUDY DESIGN

Immunohistochemical (IHC) and fluorescent in situ hybridization (FISH) assays were used to analyze and compare HER2/neu protein expression and gene amplification, respectively, in paraffin blocks from 26 women harboring stage IA to IV USPC treated at the University of Arkansas for Medical Sciences from 1997 to 2004. Chromosome 17 polysomy status by FISH was also assessed in all specimens.

RESULTS

Moderate-to-strong expression of HER2/neu protein was noted in 16 (62%) of 26 USPC samples evaluated, with 7 (27%) samples showing moderate staining (2+) and 9 (35%) showing strong staining (3+) for HER2/neu. Amplification of the ERBB2 gene by FISH was observed in 11 of the 26 (42%) cases. Protein overexpression and gene amplification were found to correlate in 100% (9 of 9) of the 3+ positive tumors and 2 out of 7 (29%) of the 2+ positive tumors. Heterogeneity was noted in 3 cases in the amplification of the HER2/neu gene within the same tumor samples with pockets of amplified tumor cells amidst nonamplified tumor cells. None of the 10 USPC cases scored by IHC as 0 or 1+ was found positive for ERBB2 amplification by FISH.

CONCLUSIONS

Amplification of the HER2/neu oncogene represents a common finding in USPC. FISH analysis should be used for confirmation of gene amplification in USPC showing 2+ expression of HER2/neu. Prior screening and selection of appropriate immunohistochemistry-positive areas may be beneficial in the selection of some USPC patients undergoing FISH analysis.

Aromatase inhibitor anastrozole for treating endometrial hyperplasia in obese postmenopausal women

This is a preliminary study investigating the efficacy of aromatase inhibitor anastrozole in treating endometrial hyperplasia in obese postmenopausal women. We administered anastrozole for 12 months to 11 obese postmenopausal women with high operative risk, in order to treat endometrial hyperplasia (four simple, five complex and two atypical). Endometrial thickness in all cases and histology too in the two cases with atypia, revealed atrophical endometrium during treatment and additional mean follow-up of 10.2 months. The safety and tolerance profile was satisfactory. Anastrozole appears to be an interesting new modality for the treatment of endometrial hyperplasia in obese postmenopausal women.

Endometrial hyperplasia/adenocarcinoma. A conventional approach

Hyperplasia of the endometrium is a process characterized by an irregular, noninvasive proliferation of glands with a variable amount of stroma. Precise classification of endometrial hyperplasia in biopsy material is important in order to identify those hyperplasias that are likely to be precursors of endometrial adenocarcinoma. The current World Health Organization (WHO) classification provides a scheme that has become widely accepted, primarily dividing hyperplasias in to those with and those without cytologic atypia while the degree of glandular crowding (simple vs. complex) has secondary importance. A wide variety of other endometrial changes, ranging from artifacts, metaplasias and polyps to well-differentiated adenocarcinoma must be considered in the differential diagnosis. Well-differentiated adenocarcinoma is diagnosed when one of 3 essential criteria is found in biopsy specimens: (1) a confluent gland pattern; (2) an extensive papillary pattern; or (3) a desmoplastic stromal response. Using the WHO classification allows segregation of endometrial hyperplasia into clinically meaningful categories. Strict morphologic criteria also enable separation of hyperplasia from well-differentiated adenocarcinoma.

Aromatase and comparative response to its inhibitors in two types of endometrial cancer

Aromatase activity (AA) was evaluated totally in 80 tumors collected from primary endometrial cancer (EC) patients. All patients were divided into cases belonging to the types I or II of EC (respectively, 50 and 30 observations). Samples of malignant endometrium from type II demonstrated inclination to the higher AA in comparison with type I samples; the difference reached level of statistical significance in non-smoking patients (p=0.02). Although no positive correlation was revealed between AA in EC tissue and percentage of cells with DNA damage in normal endometrium from the same patients, the rate of DNA damage (percent of comets, comet's tail average length, etc.) was higher in intact endometrium collected from patients with type II of the disease. In 19 tumor samples, CYP19 gene expression was evaluated by RT-PCR and level of mRNA signal demonstrated positive correlation with AA (R(s)=+0.63, p=0.05) in the whole this material. Of note, though, CYP19 mRNA expression was not revealed in six cases, and all of them belonged to the type I of disease. Finally, in 23 EC patients (15 with type I and 8 with type II of the disease) effects of 2 weeks treatment with letrozole (10 pts) and exemestane (13 pts) were evaluated in neoadjuvant setting. Although diminishing of endometrial M-echo signal and the increases in FSH and LH concentration after treatment were more pronounced in type I patients, decrease in tumor PR content (p=0.04) was more revealing in patients with type II of EC; besides, the decreases in AA in tumor tissue by the end of treatment were noted predominantly in patients with lower body weight (BMI <27.5). Thus, although type II of EC is frequently considered as hormone-independent, increased ability of this type of the tumor to estrogen biosynthesis (at CYP19 gene and protein level) may lead to the reconsideration of such conclusion and warrants further investigation. The search of possible ethnic differences in AA and in the biologic response to aromatase inhibitors in EC can be of importance too.

Association of p73 G4C14-to-A4T14 polymorphism at exon 2 and p53 Arg72Pro polymorphism with the risk of endometrial cancer in Japanese subjects

To test the association of endometrial cancer with the p73 G4C14-to-A4T14 polymorphism in exon 2 and the p53 Arg72Pro polymorphism, an incident case-control study was performed in Japanese subjects. The cases comprised 114 endometrial cancer patients, and the controls were 320 healthy females and 122 noncancer female outpatients. An unconditional logistic regression model demonstrated a significant association between the p73 AA genotype and an increased risk of endometrial cancer (OR=2.82, 95% CI=1.36-5.82), especially of type-I tumors (OR=3.24, 95% CI=1.53-6.87). In contrast, there was no significant difference in the p53 Arg72Pro genotype frequency between the controls and cases.

Histologic Type, Organ of Origin, and Wnt Pathway Status: Effect on Gene Expression in Ovarian and Uterine Carcinomas

PURPOSE

Ovarian and uterine carcinomas manifest several differentiation patterns resembling those seen in nonneoplastic epithelia of the gynecologic tract. Specific oncogene and tumor suppressor gene defects have been associated with particular differentiation patterns in carcinomas arising in either the uterus or ovary. For instance, ovarian and uterine carcinomas with endometrioid differentiation frequently show beta-catenin mutations. Whereas type of differentiation is considered in the treatment of uterine carcinomas, it does not presently contribute to decisions about treatment of ovarian carcinomas. A widely accepted view is that the accumulation of specific gene defects and gene expression changes underlies phenotypic traits of cancers, including their response to treatment.

EXPERIMENTAL DESIGN

Using oligonucleotide microarrays to assess gene expression in 103 primary ovarian and uterine carcinomas, we sought to address whether organ of origin or type of differentiation (histotype; endometrioid versus serous) had a more substantial effect on gene expression patterns.

RESULTS

We found that effects on gene expression due to organ of origin and histotype are similar in magnitude and are parallel in that organ effects are similar in the two histotypes and histotype effects are similar in the two organs. In addition, ovarian and uterine endometrioid adenocarcinomas with beta-catenin defects show a common gene expression signature largely distinct from that seen in tumors lacking such defects.

CONCLUSIONS

Our results illustrate how organ of origin, type of differentiation, and specific molecular defects all contribute to gene expression in the most common types of ovarian and uterine cancers. The findings also imply gene expression data will be of value for stratifying ovarian cancer patients for new treatment approaches.

Endometrial glandular dysplasia: a putative precursor lesion of uterine papillary serous carcinoma. Part II: molecular features

Endometrial glandular dysplasia (EmGD) may be a newly defined precursor lesion of uterine papillary serous carcinoma (UPSC) by morphology. In this report, we studied molecular changes present in EmGD by the loss of heterozygosity (LOH) approach using laser capture microdissected tissue samples. Nineteen uteri showing at least 1 focus of EmGD by morphology were selected. These cases were 12 UPSC, 2 clear cell carcinomas, 1 mixed uterine papillary serous and endometrioid carcinoma, 1 uterine carcinosarcoma, 1 serous endometrial intraepithelial carcinoma (EIC), and 2 EmGD involving endometrial polyps. Seven microsatellite polymorphic DNA markers (TP53 at 17p, D1S211, and D1S162 at 1p32, D17S1323 at 17q21, D17S1330 at 17q25, D5S346 at 5q, and D2S123 at 2p) were utilized. A total of 123 laser-captured microdissection samples from 19 cases was studied with LOH method. The frequencies and patterns of LOH were analyzed and compared among benign resting endometrium (RE), EmGD, serous EIC, and UPSC. LOH was observed for at least 1 of the 7 markers in all categories of lesions, EmGD, serous EIC, and UPSC. The frequency of LOH for EmGD ranged from 4.2% to 31.3%; the range for serous EIC was 5.9% to 78.6%; and that for UPSC was 7.7% to 62.5%. The most frequent LOH in the 3 above-cited categories of lesions was identified at 17p (TP53) and 1p (D1S162). The frequency of LOH in EmGD with markers of TP53 and D1S162 was significantly higher than in RE (p < 0.05). With markers of D1S211 and D2S123, LOH in EmGD was higher than RE, approaching to a statistically significant level. Compared with foci of serous EIC and UPSC, however, the rate of LOH in EmGD was significantly lower only with TP53 locus (31.3% vs more than 60%, p < 0.05). The difference of LOH frequency with other chromosomal markers between EmGD and serous EIC/UPSC did not reach a statistically significant level. A significantly high concordant LOH pattern was found between foci of EmGD and serous EIC/UPSC (p = 0.05). We conclude that EmGD frequently shows LOH at multiple chromosomal loci, particularly at 17p and 1p. Significantly high concordant LOH frequency between EmGD and paired serous EIC or UPSC strongly suggests that EmGD is a noncancerous precursor lesion of UPSC, probably also of serous EIC. The clinical significance of EmGD needs further studies.

Age dependent association of endometrial polyps with increased risk of cancer involvement

Background

Endometrial polyps (EMPs) are commonly encountered in routine surgical pathology practice, but opinions differ on whether they are intrinsically a marker for concurrent or subsequent malignancy. The objectives of the present study are 1) to investigate the age-group in which EMP are most commonly encountered 2) to document the age-group in which EMP are most commonly associated with malignancies 3) To investigate whether the age of diagnosis of the various carcinoma subtypes in EMPs is congruent with published data on similar malignancies arising in non-polypoid endometrium and 4) To investigate whether the histologic subtype distribution of malignancies associated with EMPs are similar or different from the distribution of malignancies arising from non-polypoid endometrium based on published data.

Patients and methods

All cases of EMPs were retrieved from the files of Yale-New Haven Hospital for the period 1986–1995. The patients were divided into 5 age groups: Each group was further subclassified based on an association (or lack thereof) of EMPs with endometrial carcinoma. Chi-square test was used to compare the proportion of malignancy associated EMPs between the age groups.

Results

We identified 513 EMPs, of which 209 (41%) were from biopsy specimens and 304 (59%) from hysterectomy specimens. Sixty six (13%) of all EMPs were malignant. The 66 malignant EMPs included 58 endometrioid, 6 serous, 1 carcinosarcoma, and 1 clear cell carcinoma. In age group >35, only 1(2.5%) of 40 EMPs was associated with endometrial malignancy. In contrast, 37(32%) of 115 EMPs were associated with malignancy in the age group > 65. The frequency of malignant EMPs increased with age and reached statistical significance in the age group >65 (p < 0.001). The most common histologic type of malignancy was endometrioid adenocarcinoma.

Conclusions

EMPs show statistically significant age dependent association with malignant tumor involvement. Careful search for malignancy, particularly in women with multiple risk factors is advised in daily practice. Additional studies are needed to address the histological features and immunohistochemical profiles in the context of association between endometrioid and high-grade endometrial carcinoma and endometrial polyps.

Reduction of Primordial Follicles Caused by Maternal Treatment with Busulfan Promotes Endometrial Adenocarcinoma Development in Donryu Rats

Ovarian dysfunction leading to hormonal imbalance plays a crucial role in uterine carcinogenesis in rats as well as women. However, the effects of a reduction in primordial follicles at birth on uterine adenocarcinoma development have hitherto not been determined. The present study was therefore conducted using female Donryu rats, a high incidence rat strain of uterine adenocarcinoma. The animals were maternally exposed to 2.5 or 5.0 mg/kg of busulfan on gestation day 14 to reduce primordial follicles, and were then initiated by intrauterine treatment with N-ethyl-N'-nitro-N-nitrosoguanidine at 11 weeks of age. Both busulfan treatment doses caused earlier occurrence of persistent estrus, with dose-dependence as compared to controls. At 15 months of age, the rats were euthanized. The incidence of uterine adenocarcinomas and multiplicity of uterine neoplastic lesions were significantly increased by the 5.0 mg/kg, but not the 2.5 mg/kg busulfan treatment. Morphologically, the ovaries exposed to busulfan treatment exhibited severe atrophy, with few or no follicles and corpus lutea. Serum 17beta-estradiol (E2), progesterone, and inhibin levels were significantly decreased in the busulfan treatment groups, with a clear dose-relation. Interestingly, only the 5.0 mg/kg busulfan treatment elevated the E2/progesterone ratio. These results provide evidence that the reduction of primordial follicles promotes uterine adenocarcinoma development in rats in association with an earlier occurrence of the persistent estrus status.

TGF-β signaling is disrupted in endometrioid-type endometrial carcinomas

OBJECTIVE

Previous studies have demonstrated deregulation of the expression and changes in the intracellular distribution of TGF-beta pathway components in human endometrial cancer (EC). The aim of this study was to assess the relationship between the expression of TGF-beta cascade components, including TGF-beta receptor type I (TGF beta RI) and type II (TGF beta RII), SMAD2, SMAD3, SMAD4, and clinicopathological features--tumor grade, FIGO classification, and depth of myometrial invasion--of type I (endometrioid-type) ECs to give some insight into the role of TGF-beta cascade components in endometrial tumorigenesis.

METHODS

The expression of TGF beta RI, TGF beta RII, SMAD2, SMAD3, and SMAD4 was evaluated both at the mRNA and protein level using reverse transcription polymerase chain reaction (RT-PCR) and ELISA, respectively.

RESULTS

Infiltrating endometrial carcinomas (less and more than half of the myometrial wall thickness) express significantly higher TGF beta RII protein level compared with non-infiltrating tumors (P = 0.04 and P = 0.01, respectively). Decreased level of SMAD2 and SMAD4 mRNAs was observed in the uterine tumors infiltrating less and more than half of the myometrial wall (P = 0.03 and P = 0.02, respectively) compared with noninfiltrating ECs. Significantly higher SMAD4 protein level in the cytoplasmic fraction of ECs was found when tumor grade and depth of myometrial invasion were considered (P < 0.05). Generally, tumor progression was associated with a decreased number of cases characterized by the presence of SMADs in the nuclear fraction only.

CONCLUSION

Our data suggest that disturbances of the TGF beta RII and SMAD4 expression as well as localization of SMADs may be important to the infiltration of the myometrial wall by the type I endometrial carcinomas.

Distinctive Gene Expression Profiles by cDNA Microarrays in Endometrioid and Serous Carcinomas of the Endometrium

Endometrial carcinomas are classified by their morphology into two major subtypes. Endometrioid carcinomas (type I) are generally estrogen dependent, well-differentiated, superficially invasive, and have a good outcome. Serous carcinomas (type II) are hormone independent, frequently deeply invasive and widely metastatic, and have a poor prognosis. Microarray technology and analysis allows us to determine if the global gene expression profiles of these two subtypes correlate with their morphologic phenotype. Fresh tissue from 18 endometrial carcinomas was studied: 7 well-, 2 moderately, and one poorly differentiated endometrioid, 4 serous carcinomas, and 4 high-grade mixed endometrioid-serous carcinomas. Labeled cDNA probes were synthesized (Cy5 for tumor, Cy3 for reference) and applied to microarrays containing 18,098 cDNA clones or ESTs. A pool of equal amounts of total RNA from each tumor served as the reference RNA. By unsupervised cluster analysis, the endometrioid carcinomas clustered together and were separate from the serous carcinomas. The high-grade mixed carcinomas clustered with the serous carcinomas. Using a statistical algorithm based on gene expression pattern and conducting a supervised analysis of the two defined groups, we have identified 315 genes that statistically differentiate type I from type II endometrial carcinomas. In addition to corroborating the predicted overexpression of known markers (e.g., ras and catenin in endometrioid carcinomas), the cDNA microarray technique has revealed novel alterations in gene expression relevant to cell cycle, cell adhesion, signal transduction, apoptosis, and tumor progression not previously implicated in endometrial carcinomas. For serous carcinomas, these include aldolase, desmoplakin, integrin-linked kinase, PKC, and metallopeptidase. In conclusion, the gene expression profiles of type I and type II endometrial carcinomas are different. Refinement of these profiles will permit more accurate diagnostic tumor classification and the development of prognosis assays.

Clinicoprognostic significance of pRb1 pathway alterations in uterine endometrial adenocarcinoma

Components of the pRb1 pathway play a pivotal role in regulating the G1/S transition in the cell cycle. This study investigated the association between pRb1-cyclin D1-cdk4-p16INK4A pathway alterations and the clinical and prognostic utility for women affected by primary uterine endometrial adenocarcinoma (EC). The study population consisted of 50 cases of EC patients who were investigated for RB1 and CDKN2A (alias p16INK4A) gene alterations, as well as for the expression pattern of pathway proteins. Altogether, pRb1 pathway alterations were noted in 54% (27 of 50) of ECs, and more frequently in advanced-stage uterine carcinomas (P=0.024, Fisher exact test). Loss of heterozygosity abnormalities in RB1 and CKDN2A coexisted with altered cyclin D1-cdk4 complex immunoreactivity only in 2 patients, both less than 50 years of age. With respect to pRb1 pathway alterations, however, the recurrence rate was not significantly different (P=0.477; log-rank test). Our results suggest that the progression of uterine endometrial adenocarcinoma is generally accompanied by increased frequency of pRb1 pathway alterations. Alterations of the retinoblastoma pathway may not be necessarily associated with the recurrence of EC.

Significance of progesterone receptor-A and -B expressions in endometrial adenocarcinoma

The progesterone receptor (PR) has two isoforms, A and B, among which PR-B is mainly involved in regulating proliferation of the uterine endometrium. In this study, immunohistochemical analysis was carried out to investigate the correlation of PR-A and -B expressions with cell cycle-regulatory proteins and clinicopathological parameters in endometrial adenocarcinoma. One hundred and forty-one endometrioid adenocarcinomas [76 with well-differentiated (G1), 35 with moderately differentiated (G2) and 30 with poorly differentiated (G3)] were used. Specimens of formalin-fixed and paraffin-embedded tissue were immunohistochemically stained using the high polymer method (HISTOFINE, NICHIREI). The percentage of positive nuclei of tumor cells observed in three high power fields was expressed as a labeling index (LI). PR-B expression significantly occurred more frequently in G1. It was inversely correlated with p53 gene mutation and p53 over expression, and also with clinicopathological variables, including myometrial and lymph-vascular space invasion and the FIGO stage. Patients with negative PR-B had a poorer prognosis than positive cases. PR-A expression was also significantly higher in G1 and was inversely correlated with Ki-67 expression and myometrial invasion, but not with prognosis. PR-A and -B expressions were significantly correlated with biologically malignant potential. Especially, PR-B expression is useful as a prognostic indicator of endometrial adenocarcinoma.

In vivo adenovirus-mediated gene transduction into mouse endometrial glands: a novel tool to model endometrial cancer in the mouse

OBJECTIVE

The lack of an endometrial epithelium-specific promoter has slowed down the development of technically advanced mouse models of endometrial cancer. The aim of this study was to test whether direct in vivo adenoviral-mediated gene delivery can be used to circumvent this problem.

METHODS

Adenoviruses expressing the LacZ reporter gene or the Cre recombinase were injected into the left horn of the mouse uterus. Histochemistry and immunohistochemistry were used to detect expression of the reporter gene as well as targeted deletion of a floxed allele.

RESULTS

Our data demonstrate that in vivo direct injection of adenoviruses can efficiently target the endometrium in the mouse, specifically transducing genes to the glandular epithelial component.

CONCLUSIONS

This approach will allow the generation of more refined and genetically defined mouse models of endometrial cancer. Endometrial gland-specific transient expression of recombinases, such as Cre, may thus be employed to delete engineered alleles of tumor suppressor genes and to activate the expression of latent oncogenes.

Insulin resistance, its consequences for the clinical course of the disease, and possibilities of correction in endometrial cancer

OBJECTIVES

To study the frequency of insulin resistance (IR) in endometrial cancer patients, its relation to the clinical course of the disease and DNA damage, and to evaluate possible approaches to the pharmacological correction of IR in the patients studied.

METHODS

The signs of insulin resistance syndrome and its association with the clinical and pathological features of the disease and DNA damage in somatic cells (micronucleus frequency in peripheral blood lymphocytes) and endometrial normal and tumor tissue (alkaline unwinding) were determined in 99 endometrial cancer patients.

RESULTS

The frequency of insulin resistance syndrome counted on the basis of fasting plasma glucose and insulin concentrations according to Duncan et al. is equal to 0.35 (95% CI 0.24-0.46), or 35%, in endometrial cancer patients who do not have a history of diabetes mellitus. Patients with well- or moderately differentiated endometrial adenocarcinomas (mostly type I) had statistically significantly higher basal and stimulated plasma insulin and C-peptide concentrations than patients with poorly differentiated endometrial adenocarcinomas or rarely encountered tumors of the endometrium (primarily type II). Interestingly, the level of fasting insulinemia positively correlates with disease stage and with local and regional tumor dissemination only in the group of patients with well- or moderately differentiated endometrial adenocarcinomas. On the other hand, hyperinsulinemia and other hormonal-metabolic disturbances typical of insulin resistance syndrome do not increase the probability of DNA damage of somatic cells (according to the data of micronucleus test). In addition, no association between hormonal-metabolic disturbances and the degree of DNA unwinding in tumor and visually unchanged endometrium was found.

CONCLUSION

Thus, insulin resistance/hyperinsulinemia is associated with a more aggressive course of the disease in certain groups of the patients but--in contrast to excessive estrogenic stimulation--does not result in increased genotoxic damage in tumor and normal tissues. The data obtained once more confirm the need for treatment and prevention measures aimed at correcting hormonal-metabolic disturbances in endometrial cancer patients and groups at risk of this disease. Such an approach might include use of antidiabetic biguanides, thiazolidinediones (glitazones), and statins.

Prolonged use of gonadotropin-releasing hormone agonist and tibolone as add-back therapy for the treatment of endometrial hyperplasia

OBJECTIVES

To investigate the response of the various hyperplastic disorders of the endometrium to a prolonged treatment with leuprolide acetate, a gonadotropin-releasing hormone agonist (GnRH-a), plus tibolone, as add-back therapy, and further to study if the tibolone addition reduces the hypoestrogenic actions of the GnRH-analogue.

METHODS

We treated 26 women with histologically confirmed simple (n = 9), complex (n = 15) or atypical (n = 2) endometrial hyperplasia (EH) for 12 months with monthly injections of 1Ampulle/3.75 mg of leuprolide acetate, followed by tibolone, 2.5mg per day per os. Every woman underwent a hysteroscopic evaluation and biopsy of the endometrium after 3 (in cases with atypical EH), 6 and 12 months of treatment, as well as after 12 and 24 months of follow-up. The clinical, paraclinical and laboratory course of the disease was followed-up by using of a climacteric scoring system and by testing of various parameters.

RESULTS

The histopathologic evaluation of the endometria revealed regression of EH in all women after 12 months of treatment, however, during the first 2 years of follow-up EH reappeared in four women (4/21, 19%). Bone mineral density and serum parameters did not show significant changes during treatment, whereas only a mild suffering from hypoestrogenic side-effects was noted.

CONCLUSIONS

It seems that the combined GnRH-a/tibolone treatment in women with EH is a potent alternative, so far as the endometrial status and the clinical course of the disease are concerned, whereas tibolone appears to act sufficiently as add-back therapy to prolonged GnRH-a treatment. The probability of relapse of the disease during the follow-up period makes the close monitoring of the endometrium after cessation of the treatment absolutely necessary.

Molecular characterization of uterine clear cell carcinoma

Clinicopathological studies support a broad classification of endometrial carcinoma into two major types, designated as type I and type II, which correlate with their biological behavior. More recently, molecular studies have provided further insights into this classification scheme by elucidating the genetic events involved in the development and progression of endometrial carcinoma. Microsatellite instability and mutations in the PTEN gene have been widely associated with type I (endometrioid) endometrial carcinoma, while p53 mutations have been identified in the majority of type II endometrial carcinoma, of which uterine serous carcinoma is the prototype. Uterine clear cell carcinoma (UCC) is an uncommon variant of endometrial carcinoma, and clinicopathological studies have produced conflicting results regarding its biological behavior with 5-year survival ranging from 21 to 75%. The molecular characteristics of endometrioid and serous carcinoma have been studied extensively; however, there have been few molecular genetic studies of the clear cell subtype. In this study, we evaluated 16 UCCs (11 pure and 5 mixed) for mutations in the p53 gene, PTEN gene and for microsatellite instability. Although we found that these alterations were uncommon in pure clear cell carcinomas, all three were identified. In addition, two cases of mixed serous and clear cell carcinoma showed an identical mutation of the p53 gene in the histologically distinct components and one case of mixed clear cell and endometrioid carcinoma had identical mutations in the PTEN and p53 genes, and microsatellite instability in both components. Our data suggest that UCC represent a heterogeneous group of tumors that arise via different pathogenetic pathways. Additional molecular studies of pure clear cell carcinoma are required to further elucidate the genetic pathways involved in its development and progression.

Identification of a novel candidate gene,CASC2, in a region of common allelic loss at chromosome 10q26 in human endometrial cancer

Allelic deletions, which are suggestive for the presence of tumor suppressor genes, represent a common event in endometrial cancer (EC). Previous loss-of-heterozygosity studies for human chromosome 10q identified a candidate deletion interval at 10q25-q26, which we further narrowed to a 160-kb region at 10q26, bounded by markers D10S1236 and WIAF3299. Using a positional candidate approach, we identified three alternative transcripts of a novel human gene, CASC2 (cancer susceptibility candidate 2; formely C10orf5). One of such transcripts, CASC2a, encodes a short protein of 102 amino acids with no similarity to any other known gene product. Three (7%) CASC2a mutations were identified in tumor DNA from 44 EC patients. While c.-156G>T and c.22C>T (p.Pro8Ser) are sequence variants with unknown functional significance, c.84delA is a mutation with a truncation effect on the predicted protein (p. Asn28fsX50). Expression studies by real-time RT-PCR on several normal and tumor cells revealed that CASC2a mRNA is downregulated in cancer, suggesting that it may act as a potential tumor suppressor gene. The very low mutation rate seems to also indicate that inactivation of CASC2a might probably be due to mechanisms different from genetic alterations.

Expression of the inhibin-alpha subunit in normal, hyperplastic and malignant endometrial tissue: an immunohistochemical analysis

OBJECTIVES

Determination of the frequency and tissue distribution of inhibin-alpha (INH-alpha) in normal, hyperplastic and malignant endometrium.

MATERIALS AND METHODS

Endometrial tissue was obtained from normal, hyperplastic (glandular-cystic hyperplasia), adenomatous hyperplasia (AH grade I to III) and endometroid adenocarcinoma and immunohistochemically characterized with INH-alpha antibody.

RESULTS

INH-alpha was expressed in normal, hyperplastic and malignant endometrium. Highest expression was observed during secretory phase and glandular-cystic hyperplasia compared to all groups. A continuous decline was noted from AH grade I to III with a significance between AH I and II.

DISCUSSION

A menstrual cycle associated expression of INH-alpha in glandular endometrial epithelium was observed. Since AH grade II and III can be considered as a precursor of endometrial cancer, INH-alpha could be a marker of cell transformation and an endometrial tumor-suppressor agent.

Alterations of pRb1-cyclin D1-cdk4/6-p16(INK4A) pathway in endometrial carcinogenesis

The retinoblastoma protein pathway (pRb1-cyclin D1-cdk4/6-p16(INK4A)) participates in the regulation of the cellular processes at the transition of G1/S phases of the cell-cycle. Derailments of this pathway, caused either by lack of pRb1 or p16(INK4A) expression or overexpression of cyclin D1 and/or cdk4/6, are implicated in the deregulation of the cell-cycle machinery, resulting in uncontrolled cell proliferation, tumor heterogeneity, invasion and metastasis. Several studies conducted so far have assessed the deregulation of the pRb1-pathway components in various human tumors and cell-lines, provided these pathway alterations play an obligatory role in tumorigenesis. This review briefly summarizes the current information on the pRb1-cyclin D1-cdk4/6-p16(INK4A) alterations in sporadic uterine cancer, placing emphasis on the influence on the dualistic model of endometrial carcinogenesis.

The coexistence of ERBB2, INT2, and CMYC oncogene amplifications and PTEN gene mutations in endometrial carcinoma

PURPOSE

To evaluate the frequency of ERBB2, INT2 and CMYC oncogene amplifications and their coexistence with PTEN gene mutations in endometrial carcinomas.

METHODS

In 54 endometrial carcinomas amplification of ERBB2, INT2 and CMYC was determined using differential polymerase chain reaction (dPCR), and mutations in all exons of PTEN were investigated by PCR-SSCP and direct sequencing methods. Results were correlated with clinicopathological features of tumors.

RESULTS

In 31 out of 54 endometrial carcinomas (57.4%) genetic defects were found within the examined genes. Of all identified defects, mutations in PTEN and the amplification of CMYC were most frequent (26/54-48.1% and 10/54-18.5%, respectively). INT2 was amplified in 5.6% (3/54) of cases. In no case did we find ERBB2 amplification. In 77.4% (24/31) of cases only one gene was damaged. Of these, 20 cases showed only PTEN mutations, three cases only CMYC, and one case only INT2 amplification. In another seven out of 31 tumors (22.5%) defects in two or three genes coexisted simultaneously: PTEN and CMYC in five cases, CMYC and INT2 in one case, and PTEN, CMYC, and INT2 in one case. We found a number of interesting relations between the location of mutations within the PTEN sequence and the presence (+) or lack (-) of CMYC amplification. In the PTEN+CMYC- tumors the PTEN mutations were most frequent in exons 1-5, and less frequent in exons 7-8 (66.7% and 33.3%, respectively). In contrast, in the PTEN+CMYC+ carcinomas the PTEN mutations were found mainly in exons 7-8 (85.7%). PTEN mutations were equally frequent in both early and more advanced endometrial carcinomas. The CMYC amplification, however, was more frequent in advanced as compared to early tumors, although this difference did not reach statistical significance.

CONCLUSIONS

Our data suggest that differences in the presence of genetic defects may reflect the different molecular pathways of endometrial carcinogenesis. These data also suggest that location of intragenic PTEN mutations and their coexistence with the CMYC amplification may play a crucial part in the development of various subtypes of endometrial carcinoma, but this preliminary suggestion requires further research.

Detection of endometrial intraepithelial neoplasia (EIN) in postmenopausal endometrium

OBJECTIVES

To detect the presence of endometrial intraepithelial neoplasia (EIN) in the endometrium of postmenopausal patients.

PATIENTS AND METHODS

Sixty-three postmenopausal patients with endometrial polyps (n=48), hyperplasia (n=12) and endometrioid carcinoma (n=3) were enrolled for this study. The diagnosis of EIN was made by using morphological criteria and immunohistochemical methods for detection of PTEN and bcl-2.

RESULTS

EIN lesions were found in cases of endometrial polyp (n=1), atrophic endometrium (n=1) and in hyperplasia (n=1). The glands were packed, showed cytological atypia and were negative for both PTEN and bcl-2. Three patients with endometrial hyperplasia had isolated PTEN-negative glands but they were still bcl-2 positive.

CONCLUSIONS

The use of immunohistochemical methods helps detect the presence of EIN in the postmenopausal endometrium but does not substitute the morphological criteria for this diagnosis.

p16INK4A alterations are accompanied by aberrant protein immunostaining in endometrial carcinomas

PURPOSE

To date, the significance of p16INK4A tumor suppressor gene inactivation in sporadic endometrial cancer (EC) has only rarely been described. In this study, we examined the alteration type and frequency of gene alterations [point mutations, aberrant promoter methylation and loss of heterozygosity (LOH)] in 50 sporadic ECs, and correlated the genetic findings with the immunohistochemical expression of the p16INK4A protein and the classical clinicopathological features.

METHODS

Gene mutations were detected by PCR-SSCP-sequencing analysis, promoter hypermethylation by methylation-specific PCR (MSP), and LOH by PCR of the STS-marker c5.1.

RESULTS

In total, p16INK4A alterations were found in 14 of 50 (28%) sporadic ECs. In six (12%) cases, two alterations occurred simultaneously. Partial p16INK4A deletions were found in four of 50 (8%) samples. There was one missense mutation (codon 70; CCC-->GCC) and one frameshift mutation (1-bp deletion in exon 2). Only 2 of 47 (4.2%) tumors exhibited aberrant promoter methylation. An allelic loss was detected in 12 of 50 (24%) carcinomas with a higher incidence in advanced endometrial carcinomas than in early-stage uterine tumors. p16INK4A alterations were generally accompanied by gene silencing, confirmed by aberrant protein immunostaining ( r=-0.442; P=0.001). There was a significant difference in the frequency of p16INK4A alterations between early (stage I; 18%) and advanced (stages II-IV; 58%) ECs ( P=0.022). One case showed complete protein loss, but absence of genetic alterations.

CONCLUSIONS

Our data indicate that p16INK4A inactivation plays a role in the tumorigenesis of the subset of sporadic ECs, particularly in cases exhibiting an aggressive clinical behavior. We demonstrate that p16INK4A methylation can act efficiently and similarly to other genetic alterations as one of the two necessary hits according to the Knudson two-hit hypothesis of tumor suppressor gene inactivation.

Analysis of racial differences in incidence, survival, and mortality for malignant tumors of the uterine corpus

BACKGROUND

In the United States, incidence rates for malignant tumors of the uterine corpus are lower among blacks than among whites, whereas mortality rates are higher among blacks. Reasons for the higher level of mortality among blacks have been debated.

METHODS

Using data from the Surveillance, Epidemiology, and End Results program, the authors compared incidence rates by histopathologic type for malignant tumors of the uterine corpus (including uterus, not otherwise specified) during the period 1992-1998 among white Hispanic, black, and white non-Hispanic patients. The authors also compared cumulative relative survival rates for blacks and whites by histopathologic type and by other factors, and they calculated estimated type-specific mortality rates.

RESULTS

Overall incidence (per 100,000 woman-years) of corpus malignancy was significantly lower among white Hispanics (14.04; 95% confidence interval [CI], 13.39-14.72) and blacks (15.31; 95% CI, 14.61-16.04) compared with white non-Hispanics (23.43; 95% CI, 23.06-23.81). Compared with white non-Hispanics, blacks had significantly higher incidence rates of serous/clear cell carcinoma (rate ratio, 1.85; 95% CI, 1.61-2.12), carcinosarcoma (rate ratio, 2.33; 95% CI, 1.99-2.72), and sarcoma (rate ratio, 1.56; 95% CI, 1.31-1.86). Survival was worse for blacks than for whites in every histopathologic category and in 'usual' types of endometrial adenocarcinoma, stratified by stage, grade, and age. Rare aggressive tumor types accounted for 53% of mortality among blacks, compared with 36% among whites.

CONCLUSIONS

Less favorable outcomes for usual types of endometrial adenocarcinoma and for rare aggressive tumors contribute equally to the relatively high mortality due to corpus cancer among black women.

Progestin suppresses matrix metalloproteinase production in endometrial cancer

OBJECTIVES

Endometrial carcinoma (EC) is one of the few cancers where there is a clear relationship between excessive hormone stimulation and malignant transformation. In this study we have analyzed the effects of the female sex steroids estrogen and progesterone on matrix metalloproteinases (MMP-9 and -2) production in primary EC cells and EC cell lines. MMPs are implicated in cancer invasion via mechanisms including extracellular matrix degradation and the processing of a range of molecules, including growth factors and cytokines.

METHODS

Cells were isolated from biopsies collected from three cancer patients undergoing hysterectomy for grade 1 endometrial adenocarcinoma and two patients undergoing procedures unrelated to EC. These cells plus the EC cell lines Ishikawa and HEC-1A were cultured without hormones or with medroxyprogesterone acetate (MPA), estradiol (E(2)), or these hormones in combination. Gelatin and reverse zymography were used to analyze MMPs and TIMPs, respectively, in culture medium. RT-PCR was used to characterize steroid receptor expression.

RESULTS

Cell lines differed from primary cells in the range and abundance of MMPs secreted. Treatment with MPA significantly reduced proMMP-9, proMMP-2, and MMP-2 release from primary EC cancer and stromal cells. Treatment with E(2) alone or MPA + E(2) had no significant effect on MMP expression. Primary EC and stromal cells also showed a loss of the progesterone B receptor isoform.

CONCLUSION

EC cells retain the suppression of MMPs by progesterone, seen in normal endometrial cells. These data provide a rationale for the use of progestin therapy in the treatment of early stage grade 1 endometrial carcinomas.

Tumor estrogen content and clinico-morphological and endocrine features of endometrial cancer

OBJECTIVES

To compare estrogen concentrations in endometrial cancer tissue with those in macroscopically normal endometrium and with certain morphological characteristics of the tumor and endocrine parameters in patients.

METHODS

The estradiol content was evaluated by radioimmunoassay after homogenization and extraction in 78 adenocarcinomas (61 from postmenopausal patients).

RESULTS

Higher concentrations of estradiol in tumor tissue samples than in macroscopically normal endometrium were found in patients of both reproductive and postmenopausal age. This difference was the same in patients with either endometrial carcinoma type I or type II. No association between tumor steroid receptor levels, estradiol concentrations in blood serum, and timing of menopause with intratumoral estradiol contents was discovered. Estradiol concentrations in tumor tissues correlated positively with the clinical stage of disease and rate of tumor invasion (in patients with peripheric/lower type of fat topography), and negatively with tumor differentiation stage (in patients with central/upper type of fat topography) and the percentage of intact double-stranded DNA in normal endometrium.

CONCLUSIONS

Tumor estrogen content in endometrial cancer has clinical significance that is modified in the presence of certain endocrine characteristics related to insulin resistance. The role of local estrogen production (aromatase activity) in this setting deserves special study.

Loss of expression of MLH1, MSH2, MSH6, and PTEN related to endometrial cancer in 68 patients with endometrial hyperplasia

Derangements in the tumor suppressor gene PTEN and the mismatch-repair genes, hMLH1, hMSH2, and hMSH6, have an important role in endometrial carcinogenesis. The purpose of this study was to assess immunohistochemically the pattern of protein expression for these genes in 68 patients with endometrial hyperplasia and to determine the relation of protein expression to cancer development or coexistence of cancers. Loss of expression of these genes also was evaluated as potential tumor markers for clinical use. PTEN and hMLH1 both showed loss of expression in 55% of specimens from 18 patients with subsequent or coexisting carcinoma. D&C specimens from 50 patients who did not develop cancer (10 patients underwent hysterectomy within 2 years; 40 had no hysterectomy; follow-up of 10-20 years), expressed protein at a much higher frequency (92% for PTEN and 98% for hMLH1). The parameter with the strongest independent relation to subsequent or coexisting carcinoma in a stepwise multiple logistic regression analysis was hMLH1. Evaluation of the investigated factors as prognostic markers for tumor development showed high specificity (92% for PTEN, 98% for MLH1) at the expense of sensitivity (56% for PTEN, 56% for MLH1). The results were compared with the results of the computerized image analysis algorithm, the D-score.

P53 expression in spontaneous and estradiol-induced endometrial hyperplasia during menopause

OBJECTIVE

To determine the percentage of endometrial hyperplasia positive for p53 expression in both spontaneously occurring cases or following the use of unopposed estradiol.

METHODS

Fifty-four postmenopausal patients with endometrial hyperplasia diagnosed by endometrial biopsy and hysteroscopy were recruited to this study. Thirty-three patients had used unopposed estradiol for periods of time from 1 to 3 years. P53 expression was detected in paraffin-embedded endometrial specimens by immunohistochemical methods.

RESULTS

The percentage of endometrial hyperplasia positive for p53 expression was significantly greater in spontaneously occurring hyperplasia than in cases induced by the unopposed use of estradiol.

CONCLUSION

Endometrial hyperplasia caused by the unopposed use of estradiol during menopause probably harbors fewer genomic errors than those cases occurring spontaneously.

Endometrial hyperplasia, polyps, and adenomyosis associated with unopposed estrogen in rhesus monkeys (Macaca mulatta)

The purpose of this study was to evaluate the effects of estrogen and progesterone on the vaginal mucosa and their role in vaginal transmission of simian immunodeficiency virus. Incidentally, endometrial hyperplasia was observed in estrogen-treated monkeys at necropsy. Six adult female rhesus monkeys (Macaca mulatta) were ovariectomized and 120 days later received two subcutaneous implants, each containing 200 mg estradiol. The animals were sacrificed 17-27 months later and the uterus examined at necropsy. All the monkeys had simple endometrial hyperplasia, some with polyps or adenomyosis, at the time of necropsy. The severity of the changes correlated with the time between implantation and necropsy. The lesions were similar to endometrial hyperplasia caused by unopposed estrogen in women, but occurred over a time period that is suitable for experimental manipulation. Rhesus monkeys could be used as a model to test the safety of various combinations of sex steroids for the prevention of postmenopausal symptoms in women.

Systemic therapy for gynecological neoplasms: ovary, cervix and endometrium

Early-stage endometrial carcinomas should be treated by total abdominal hysterectomy and bilateral salpingo-oophorectomy. In a small subset of patients, who wish to have children, conservative treatment (hormonal therapy) could be considered. The most effective agents for palliation of advanced disease are doxorubicin plus cisplatin.

Neoadjuvant therapy of endometrial cancer with the aromatase inhibitor letrozole: endocrine and clinical effects

OBJECTIVE

To investigate the short-term hormonal and clinical effects of the aromatase inhibitor letrozole (Femara) in patients with endometrial cancer.

MATERIALS AND METHODS

Ten previously untreated, post-menopausal patients (mean age 59 years) with endometrial cancer, predominantly stage I disease, received letrozole 2.5mg per day for 14 days before surgery. Clinical, sonographic, morphologic, cytologic, and hormonal-metabolic parameters (blood estradiol, follicle-stimulating hormone (FSH), luteinizing hormone (LH), glucose, and cholesterol by radioimmunoassay, enzyme immune assay, or enzyme-colorimetric methods; tumor progesterone receptors by ligand-binding assay; and aromatase activity by 3H-water release assay) were evaluated before and after treatment.

RESULTS

Treatment was well-tolerated in all patients. In two patients, pain relief in the lower part of the belly and/or decrease in intensity of uterine discharge was reported. In the three cases, substantial decreases in endometrial M-echo (ultrasound) signal were noted; the mean value of this parameter after treatment was 31.1% lower than before treatment. Blood estradiol concentration decreased by an average of 37.8% after letrozole therapy, and tumor progesterone receptor levels and aromatase activity decreased by 34.4 and 17.5%, respectively. Treatment with letrozole did not influence surgery.

CONCLUSIONS

These data show that short-term treatment with letrozole in the neoadjuvant setting resulted in some positive clinical changes. Longer-term and larger-scale trials of neoadjuvant letrozole in endometrial cancer are warranted.

The postmenopausal ovary as an androgen-producing gland; hypothesis on the etiology of endometrial cancer

Postmenopausal estrogens originate from the peripheral conversion of androgens, which are produced by the adrenal glands and the ovaries. Estrogens are considered to contribute to the neoplastic development of endometrium. Hyperplasia of ovarian stroma is associated with an increased androgen production by the ovaries and with the development of endometrial pathology. We hypothesize that, in cases of endometrial pathology, an increased production of aromatizable androgens by postmenopausal ovaries will lead to elevated prehormone availability for estrogen formation in utero. Following the conversion of ovarian androgens, a reaction catalyzed by the cytochrome p450 aromatase, estrogens may function as a local mitogenic factor eventually leading to the development of endometrial cancer. We consider the local availability of androgens and the local activity of aromatase relevant for this process. If this hypothesis proves to be right it may give rise to the introduction of aromatase inhibitors in treatment strategies of hormone dependent endometrial malignancies.

CYP17 genetic polymorphism in endometrial cancer: are only steroids involved?

Initiation and/or promotion of endometrial cancer is known to be associated with estrogen and androgen (androstenedione) excess as well as with hyperinsulinemia/insulin resistance. It is possible that some allelic polymorphisms of the genes involved in steroidogenesis or steroid metabolism contribute to endometrial cancer susceptibility. We evaluated here the role of CYP17 biallelic (MspAI) polymorphism in 114 endometrial cancer patients compared with 182 healthy women. Our data demonstrated that A2/A2 CYP17 genotype, considered on the basis of initial breast cancer studies as 'unfavorable', was under-represented in endometrial cancer group (odds ratio 0.48, 95% confidence interval 0.25-0.89) that confirmed results of two other recent investigations. Carriers of this genotype were characterized by having lower blood insulin (by 120 min of oral glucose tolerance test 36.7+/-3.9 microU/ml vs. 90.4+/-16.7 microU/ml in postmenopausal women with A1/A1 genotype, P=0.04) and C-peptide levels (after night fasting 575.2+/-78.3 pg/ml vs. 978.9+/-115.7 pg/ml, respectively, P=0.04). No significant difference was found between the mean concentrations of testosterone, dehydroepiandrosterone sulfate and estradiol concentrations in patients-carriers of separate CYP17 genotypes. Thus, CYP17 polymorphism (namely, carrying the 'normal' A1/A1 genotype) might be one of the risk factors for endometrial cancer development. A1/A1 CYP17 variant may be associated with untraditional (non-steroidal) pathways that calls for corresponding preventive measures in high-risk groups.

Bcl-2, iNOS, p53 and PCNA expression in normal, disordered proliferative, hyperplastic and malignant endometrium

We attempted to determine Bcl-2, inducible nitric oxide synthase (iNOS), p53 and proliferating cell nuclear antigen (PCNA) expression, and the relationships between them, in endometrioid adenocarcinomas and precursor lesions. Expression of Bcl-2, iNOS, p53 and PCNA were investigated immunohistochemically in 91 samples from benign (proliferative (pEM), secretory (sEM), disordered proliferative (dEM), inactive/atrophic (aEM), hyperplastic endometrium) and malignant endometrial tissue. Staining scores for Bcl-2 in the dEM, endometrial hyperplasia (EMH) and endometrioid cancer (ECA) groups were higher than in the pEM group (P = 0.004; P = 0.036 and P = 0.020, respectively). A significant difference in proliferating cell nuclear antigen staining was found between simple and complex EMH samples (P = 0.000). An inverse relationship was found between iNOS and p53 in the hyperplasia group (r = -0.533, P = 0.019). While a significant difference was found in p53 staining in ECA between the pEM, dEM and EMH groups, no such difference was found in iNOS staining. In addition, there was no direct relationship between iNOS and p53 in the ECA group. It was concluded that the interaction between iNOS, p53 and Bcl-2 in proliferative processes in the development of type 1 endometrioid adenocarcinomas is different from that in tumors originating in other organs.

Risk factors for endometrial hyperplasia: results from a case-control study

We analyzed epidemiologic characteristics of women at risk for endometrial hyperplasia (EH), using data from a case-control study. One hundred twenty nine women aged 35-73 (median 51 years) with histologically confirmed complex endometrial hyperplasia without atypies identified at the University of Milan during the period 1990-99 were examined. Controls were 258 non hysterectomized women aged 36-74 (median 52 years), admitted to a network of hospitals covering the same area where cases had been identified for conditions other than gynecological, malignant, or hormone-related. Cases with EH were more educated than controls (OR > 12 years of education vs. < 7: 2.8, 95% CI 1.7-4.8), more frequently obese (OR 2.7, 95% CI 1.5-5.0) and diabetic (OR 2.4, 95% CI 0.8-6.9). Parous women (OR 1.8) and women reporting induced abortions (OR 1.6) showed an increased risk of EH, but the associations were not statistically significant. Compared to premenopausal women, the OR of EH was 0.2 (95% 0.1-0.5) for postmenopausal ones. Compared to women reporting menopause at age 50 or less, the OR of endometrial hyperplasia was 1.5 (95% CI 0.6-3.5) and 2.2 (95%CI 0.7-6.7), respectively, in women with menopause at age 50-52 and > or = 53. Considering postmenopausal women only the OR was 3.1 (95% CI 1.1-9.3) for use of hormonal replacement therapy (HRT). We conclude that this study indicates that high education, obesity, diabetes, and HRT use increase the risk of endometrial hyperplasia.

Assessment of the quality and frequency of mutations occurrence in PTEN gene in endometrial carcinomas and hyperplasias

The quality and frequency of mutations in PTEN gene were assessed in 59 carcinomas and 6 hyperplasias of the endometrium in women. Screening for mutations was done in all exons of PTEN gene by the PCR-SSCP analysis and DNA sequencing. Results were correlated with histological status and clinical features of endometrial carcinomas. In 45.8% (27/59) of carcinomas, 36 somatic mutations were detected in PTEN gene. In seven carcinomas, two mutations and in one carcinoma three mutations coexisted simultaneously. Moreover in 33.3% (2/6) of hyperplasia cases mutations were shown. Most identified mutations (57.9%) were present in exons 5 and 8, less frequently in exons 2 (15.8%) and 7 (13.2%) and they were least frequent in exons 1 and 3 (5.3% each). No mutations were found in exons 4, 6 and 9. Of all identified mutations, 73.7% of those resulting in truncated protein were present due to deletions, insertions and nonsense mutations. Missense mutations accounted for 13.2% of mutations and they were present only in exon 5. One point mutation (2.5%) was in intronic splice site. The remaining 10.5% of mutations were neutral polymorphisms. No statistically significant correlation were found between the frequency of PTEN gene mutations and the clinical stage of endometrial carcinomas. However, evident statistically significant, reverse correlation were observed between the frequency of mutations and the grade of morphological differentiation of the diseases (chi(2)=7.2393, alpha=0.0071). In conclusion, our data support the view that PTEN gene mutations are frequent events involved in development of endometrial carcinomas in women.

Expression of cyclin D1 in normal, metaplastic, hyperplastic endometrium and endometrioid carcinoma suggests a role in endometrial carcinogenesis

CONTEXT

Endometrioid carcinoma is often preceded by characteristic histopathologic lesions known as endometrial hyperplasia. Estrogen appears to be involved in the development of endometrioid carcinoma. Other mechanisms of endometrial carcinogenesis include mutations in p53 and PTEN tumor suppressor genes and overexpression of cyclin D1. However, the pattern of cyclin D1 expression is not well defined in normal, hyperplastic, neoplastic, and metaplastic endometrium.

DESIGN

Cyclin D1 immunohistochemical analysis was used to evaluate 108 fixed, paraffin-embedded endometrial biopsy specimens and uterine resections obtained from 108 patients. Specimens included proliferative and secretory endometria, simple and complex hyperplastic lesions, and endometrioid adenocarcinoma. Normal and metaplastic surface epithelia were also evaluated independently of glandular morphologic features.

RESULTS

Cyclin D1 was significantly overexpressed in glands with complex hyperplasia and endometrioid adenocarcinoma compared with proliferative or secretory endometrium and simple hyperplasia. Significant overexpression was also noted in papillary, syncytial, and squamous metaplasias compared with normal surface epithelium or epithelium with tubal metaplasia.

CONCLUSION

Overexpression of cyclin D1 increases from normal endometrium to hyperplasia and carcinoma, suggesting that it may play a role in endometrial carcinogenesis. Overexpression of cyclin D1 in endometrial glands was independent from overexpression of cyclin D1 in surface metaplastic epithelium.

Markers of proliferative activity are predictors of patient outcome for low-grade endometrioid adenocarcinoma but not papillary serous carcinoma of endometrium

On the basis of pathogenesis, two types of endometrial cancer can be recognized. Type 1 endometrial carcinomas are relatively indolent tumors that develop after prolonged estrogen stimulation, on a background of endometrial hyperplasia. Type 2 endometrial carcinomas are aggressive tumors that are not associated with hyperplasia or estrogen excess. The aim of this study is to evaluate the prognostic significance of tumor proliferative activity in early-stage endometrial cancer by using mitotic index and immunostaining, comparing Type 1 (endometrioid) and Type 2 (papillary serous carcinoma) tumors. The mitotic index, MIB-1, and p53 immunostaining in 39 tumors from patients with low-grade Stage Ia or Ib endometrioid adenocarcinoma; as well as 23 tumors from patients with Stage I papillary serous carcinoma. In low-grade endometrioid adenocarcinoma, mitotic and MIB-1 indices were statistically significant independent prognostic indicators (P =.004 and P =.018, respectively), and both were strongly correlated with p53 expression (P =.01 and P =.006, respectively). The mean mitotic index was 5 mitoses/10 high-power fields, and mean MIB-1 index was 27.5%. There was no significant correlation between mitotic or MIB-1 indices and patient outcome or p53 expression in papillary serous carcinoma. The mean mitotic index was 31 mitoses/10 high-power fields, and mean MIB-1 index was 30.5% in these tumors. p53 expression and proliferative indices are strongly correlated in low-grade endometrioid adenocarcinoma. MIB-1 and mitotic indices are independent prognostic indicators in these tumors. Papillary serous carcinoma of endometrium is rapidly proliferative in tumors even at an early stage, and quantification of proliferative activity in these tumors does not allow prediction of patient outcome.

Toxicity of antiestrogens

The object of this article is to review briefly the preclinical and clinical safety of some antiestrogens. Tamoxifen, toremifene, droloxifene, and idoxifene are polyphenylethylene antiestrogens, whereas the pure antiestrogen, ICI 182,780 or faslodex, as well as raloxifene, is of a different structure. Tamoxifen has been shown to be genotoxic in several studies. It induces unscheduled DNA synthesis in rat hepatocytes and micronuclei in MCL-5 a cells in vitro. Tamoxifen also induces aneuploidy in rat liver in vivo and chromosome aberrations and micronuclei in mouse bone marrow. Toremifene has also shown to be genotoxic, but to a far lower extent, by inducing micronuclei in MCL-5 a cells in vitro and by inducing aneuploidy in rat liver in vivo. Tamoxifen has been shown to be hepatocarcinogenic in the rat in at least four independent long-term studies. The initiation of tumors in the rat is the result of metabolic activation by cytochrome P450 isoenzymes to an electrophile(s) that binds irreversibly to DNA. The other antiestrogens have not been shown to be carcinogenic in rodents. In several independent clinical studies, the risk of endometrial cancer has increased among tamoxifen-treated women. After reviewing the available data, the International Agency for Research on Cancer concluded that there was sufficient evidence to show that tamoxifen is a class I human carcinogen. The increased risk for endometrial cancer occurs predominantly among women who are 50 years old or older and who have been treated with tamoxifen. It is not yet clear whether the uterine tumor formation is a result of genetic mechanisms, analogous to those seen in the rat liver or due to the estrogen agonist action of tamoxifen. However, the other antiestrogens with a more or less similar intrinsic estrogenic potential have not been shown to be carcinogenic in humans.

Nuclear receptors in cell life and death

The balance between cell proliferation and programmed cell death (apoptosis) determines body patterns during animal development and controls compartment sizes, tissue architecture and remodeling. The removal of primordial structures by apoptosis allows the organism to develop sex specifically and to adapt for novel functions at later stages; apoptosis also limits the size of evolving structures. It is a ubiquitous function that is essential for all cells. Although inappropriate regulation or execution of apoptosis leads to disease, such as cancer, there is now evidence for its great therapeutic potential. This would be particularly true if apoptosis could be targeted at defined cell compartments, rather than acting ubiquitously like chemotherapy. Here, we discuss the potential of nuclear receptor ligands, many of which act through their cognate receptors in defined body compartments as modulators of cell life and death, with special emphasis on the molecular pathways by which these receptors affect cell-cycle progression, survival and apoptosis.

Endometrioid adenocarcinomas of the uterine corpus in women younger than 50 years of age can be divided into two distinct clinical and pathologic entities based on anatomic location

BACKGROUND

This study used the clinicopathologic profiles of Japanese women younger than 50 years of age with endometrial carcinoma to distinguish the clinicopathologic features of carcinomas of the lower uterine segment (LUS) from those of carcinomas of the corpus mucosa proper (CMP).

METHODS

Eighty-eight endometrial carcinomas in women younger than 50 years old (25.3%) were selected from our file of 348 Japanese women with endometrial carcinoma. Seventy-two were classified as carcinomas of the CMP and 16 carcinomas of the LUS. A tumor was judged to be a carcinoma of the LUS when it involved a continuous area ranging from the lower corpus to the upper cervix with or without intervention of a portion of uninvolved LUS.

RESULTS

The mean ages of women with carcinomas of the CMP and LUS were 41.2 and 39.0 years, respectively. In comparison to carcinomas of the LUS, carcinomas of the CMP were more strongly associated with reproductive risk factors including parity (P = 0.01) and polycystic ovary syndrome (P = 0.02). There was no significant difference in body mass index or the incidence of diabetes mellitus and hypertension between women presenting with carcinomas of the CMP and LUS. Histologically, carcinomas of the LUS more frequently showed a high-grade endometrioid tumor (P = 0.02) with deep myometrial invasion (P < 0.01) and were less associated with endometrial hyperplasia (P < 0.01) than those of the CMP.

CONCLUSIONS

Carcinomas of the LUS occurred predominantly in women younger than 50 years of age and had clinicopathologic features distinct from carcinomas of the CMP in women younger than 50 years of age.