DNA ploidy, cell proliferation and steroid hormone receptors in endometrial hyperplasia and early adenocarcinoma

Molecular characterization of Wdr13 knockout female mice uteri: a model for human endometrial hyperplasia

Endometrial hyperplasia (EH) is a condition where uterine endometrial glands show excessive proliferation of epithelial cells that may subsequently progress into endometrial cancer (EC). Modern lifestyle disorders such as obesity, hormonal changes and hyperinsulinemia are known risk factors for EH. A mouse strain that mimics most of these risk factors would be an ideal model to study the stage-wise progression of EH disease and develop suitable treatment strategies. Wdr13, an X-linked gene, is evolutionarily conserved and expressed in several tissues including uteri. In the present study, Wdr13 knockout female mice developed benign proliferative epithelium that progressed into EH at around one year of age accompanied by an increase in body weight and elevated estradiol levels. Molecular characterization studies revealed increase in ERα, PI3K and a decrease in PAX2 and ERβ proteins in Wdr13 mutant mice uteri. Further, a decrease in the mRNA levels of cell cycle inhibitors, namely; p21 and cyclin G2 was seen. Leukocyte infiltration was observed in the uterine tissue of knockout mice at around 12 months of age. These physiological, molecular and pathological patterns were similar to those routinely seen in human EH disease and demonstrated the importance of WDR13 in mice uterine tissue. Thus, the genetic loss of Wdr13 in these mice led to mimicking of the human EH associated metabolic disorders making Wdr13 knockout female mice a potential animal model to study human endometrial hyperplasia.

An estrogen-induced endometrial hyperplasia mouse model recapitulating human disease progression and genetic aberrations

Endometrial hyperplasia (EH) is a condition originating from uterine endometrial glands undergoing disordered proliferation including the risk to progress to endometrial adenocarcinoma. In recent years, a steady increase in EH cases among younger women of reproductive age accentuates the demand of therapeutic alternatives, which emphasizes that an improved disease model for therapeutic agents evaluation is concurrently desired. Here, a new hormone-induced EH mouse model was developed using a subcutaneous estradiol (E2)-sustained releasing pellet, which elevates the serum E2 level in mice, closely mimicking the effect known as estrogen dominance with underlying, pathological E2 levels in patients. The onset and progression of EH generated within this model recapitulate a clinically relevant, pathological transformation, beginning with disordered proliferation developing to simple EH, advancing to atypical EH, and then progressing to precancerous stages, all following a chronologic manner. Although a general increase in nuclear progesterone receptor (PR) expression occurred after E2 expression, a total loss in PR was noted in some endometrial glands as disease advanced to simple EH. Furthermore, estrogen receptor (ER) expression in the nucleus of endometrial cells was reduced in disordered proliferation and increased when EH progressed to atypical EH and precancerous stages. This EH model also resembles other pathological patterns found in human disease such as leukocytic infiltration, genetic aberrations in β-catenin, and joint phosphatase and tensin homolog/paired box gene 2 (PTEN/PAX2) silencing. In summary, this new and comprehensively characterized EH model is cost-effective, easily reproducible, and may serve as a tool for preclinical testing of therapeutic agents and facilitate further investigation of EH.

5-Aza-2′-Deoxycytidine Improves the Sensitivity of Endometrial Cancer Cells to Progesterone Therapy

Objective

Progesterone has been proven to have limited effects on endometrial cancers (ECs), mainly owing to the down-regulation of progesterone receptor (PR). Here, we explored whether 5-aza-2′-deoxycytidine (5-aza-CdR), a demethylating agent, could enhance the susceptibility of EC cells to medroxyprogesterone acetate (MPA).

Methods

Ishikawa and KLE cell lines were treated with 5-aza-CdR and/or MPA. The expression of PR, PR target genes, and matrix metalloproteinase (MMP) was investigated by real-time polymerase chain reaction and Western blot. Promoter methylation was detected by methylation-specific polymerase chain reaction. The effects of 5-aza-CdR and/or MPA on cell proliferation, apoptosis, and invasion of EC cells were evaluated by 2-(4-Iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium assay, flow cytometry, invasion assay, and gelatin zymography, respectively.

Results

5-Aza-2′-deoxycytidine significantly increased the expression of PR and its downstream targets by demethylating PR promoter in both Ishikawa and KLE cells. 5-Aza-2′-deoxycytidine combined with MPA synergistically suppressed the EC cell growth by inducing cell cycle arrest at G2/M phase and apoptosis. Furthermore, 5-aza-CdR synergized with MPA to inhibit the invasion of EC cells, perhaps owing to the down-regulation of MMP-2 and MMP-9 expression and activity.

Conclusions

5-Aza-2′-deoxycytidine and MPA synergistically inhibit EC cell growth and invasion. Their combined use may provide a new effective therapeutic opportunity for endometrial carcinoma.

Effect of levonorgestrel IUD and oral medroxyprogesterone acetate on glandular and stromal progesterone receptors (PRA and PRB), and estrogen receptors (ER-α and ER-β) in human endometrial hyperplasia

OBJECTIVES

The effect on progesterone and estrogen receptor expression in glands and stroma after two different treatment regimens of endometrial hyperplasia was determined.

METHODS

Pre- and post-treatment paraffin-embedded endometrial hyperplasia specimens from women treated with levonorgestrel (LNG) intrauterine device (n = 21) and women treated with 10 mg medroxyprogesterone acetate (MPA) for 10 days per cycle (n = 29) were examined immunohistochemically and evaluated by H-score (a semi-quantitative microscopical method evaluating staining intensity and number of stained cells, scale 0-3) for changes in expression of PRA (progesterone receptor A), PRB (progesterone receptor B), ER-alpha (estrogen receptor-alpha), ER-beta (estrogen receptor-beta) and AR (androgen receptors) after 3 months of treatment.

RESULTS

All the patients in the LNG IUD group responded to treatment with no sign of hyperplasia after 3 months, while only about half of the patients given MPA orally responded. Expression of PRA, PRB, ER-alpha and ER-beta were markedly reduced after progestin treatment in both treatment groups but the reduction was much more pronounced in the LNG group (H-score for PRA was reduced from 2.61 to 0.11 in glands and from 2.26 to 0.09 in stroma in LNG group. Corresponding reduction for PRB in the LNG group was from 1.96 to 0.11 and from 0.83 to 0.01. PRA was reduced from 2.53 to 1.78 in glands and from 1.93 to 1.30 in stroma in the MPA group. Corresponding reduction for PRB in the MPA group was from 2.02 to 1.25 in glands and from 0.80 to 0.34 in stroma). Weak and focal stromal expression of AR was demonstrated in 22% of the specimens before but not after therapy. There was a statistically significant reduction in both PR and ER among the responders whereas non-responders showed no statistical change after treatment.

CONCLUSION

The present study shows that LNG IUD causes an almost complete down-regulation (lack of immunohistochemical expression) of PR expression and a considerable down-regulation of ER expression in both glands and stroma. The changes in receptor expression were markedly less pronounced after treatment with intermittent oral MPA. The differences in receptor expression among responders and non-responders might serve as possible markers for therapy response.

Can flowcytometric DNA studies forecast the prognosis of endometrial hyperplasia?

OBJECTIVES

The study is investigating the relation of the ploidy pattern and cell cycle kinetics to different types of endometrial hyperplasia to select the high-risk women who will need strict follow up surveillance.

STUDY DESIGN

An observational study of 152 patients with endometrial hyperplasia. Endometrial samples were subjected to flowcytometric study of the nuclear DNA content to determine the ploidy pattern and cell cycle kinetics.

RESULTS

The mean age of women was 46.3+/-3.6 years. 15.8% of women were nulliparae, 36.8% were diabetic and 43.6% were hypertensive. 48.7% of women were obese (BMI>30). Most of endometrial samples (88.2%) were simple endometrial hyperplasia without atypia. The cell cycle kinetics in different types of endometrial hyperplasia shows that there were significant statistical differences as regards the S-phase fraction and proliferative index (PI) between typical and atypical hyperplasia.

CONCLUSION

The study of cell cycle kinetics by flowcytometry might help in picking up, among all women with endometrial hyperplasia, the group of patients who need further close and strict follow up by endometrial pathologic study. This is going to minimize the cost and invasiveness of surveillance of patients with various grades of endometrial hyperplasia.

Immunohistochemical analysis of c-myc, c-jun and estrogen receptor in normal, hyperplastic and neoplastic endometrium

To evaluate the role of c-jun and c-myc proto-oncogenes in normal, hyperplastic and neoplastic endometrium in relation to estrogen receptor (ER) status and to investigate whether these genes can be related to other histopathological features of endometrial carcinoma, 32 endometrial carcinomas, 38 endometrial hyperplasias and 22 cyclic endometria (10 proliferative and 12 secretory) were evaluated histologically. Endometrial hyperplasia cases were classified as simple and complex hyperplasia without atypia, and atypical hyperplasia. Endometrial carcinoma cases were subtyped according to the International Society of Gynecological Pathologists. Modified FIGO system was used for both grading and staging. Immunohistochemical examination was performed using antibodies to ER-alpha, c-myc and c-jun with streptavidin-biotin-peroxidase technique. The mean percentage of ER-alpha positive cells changed cyclically during the menstrual cycle, and it was the highest (96%) and the lowest (31.6%) in proliferative and carcinomatous endometrium, respectively. There was a statistically significant difference between proliferative and secretory phases and proliferative and carcinomatous endometrium in relation to ER-alpha staining (p<0.05). There was also a statistically significant difference with respect to ERalpha reactivity between secretory phase and each hyperplastic group, as well as between the carcinoma group and each hyperplastic group (p<0.05). Although not significant, the mean percentage of c-myc expressing cells in the carcinoma group was higher (15.3%) than that of proliferative phase and hyperplastic groups. The mean percentage of c-jun positive cells in proliferative endometrium was slightly higher than in secretory endometrium, and it was the highest in atypical hyperplastic endometrium (28.3%), but there was no statistically significant difference between the groups. In carcinoma cases, a positive correlation was observed between c-jun positivity and tumor grade (p=0.027, r=0.3908), but such a correlation with c-myc was not found. A positive correlation was detected between ER-alpha and c-myc expression (p=0.038, r=0.3686). A progressive loss of ER seems to be correlated with increasing malignant transformation. C-myc expression might play a role in the development of endometrial carcinoma via ER. The association between c-jun and ER appears to be lost in endometrial carcinoma. The relationship between c-myc, c-jun and ER appears to be altered in endometrial carcinoma compared to that of menstrual endometrium.

Matrix metalloproteinase-26 (matrilysin-2) expression is high in endometrial hyperplasia and decreases with loss of histological differentiation in endometrial cancer

OBJECTIVE

Matrix metalloproteinases (MMPs) are key players in the degradation of extracellular matrix and basement membranes, and are thus important in tumor invasion. Recently, MMP-26 (endometase), a novel matrilysin-type member of the MMP family, was cloned from an endometrial tumor. This study examines the expression of MMP-26 mRNA in hyperplastic, premalignant and malignant endometrial samples, and compares with normal endometrial tissue.

METHODS

Endometrial carcinoma samples (19) were histologically classified as well, intermediately and poorly differentiated. Samples with hyperplasia (n = 15) were classified as simple, complex, or complex with atypia. Normal endometrial specimens (n = 39) were classified according to an ideal 28-day menstrual cycle and subsequently grouped in the early, middle, and late parts of the cycle. All samples were analyzed using in situ hybridization and real time PCR. The probes used for in situ hybridization and real time PCR recognized non-overlapping sequences. MMP-26 protein was localized by immunohistochemistry.

RESULTS

MMP-26 mRNA was exclusively localized in the epithelial component of normal, hyperplastic, premalignant, as well as malignant samples. It was not found in the stroma of any tissue category. Quantifications with real time PCR as well as semi-quantifications of the in situ hybridization signal revealed maximal levels in normal tissue at midcycle and in endometrial hyperplasia both with and without atypia. The amount of MMP-26 mRNA decreased progressively with loss of histological differentiation in malignant samples. Immunostaining localized MMP-26 in epithelial glandular and luminal cells, in vessel walls, and in tumor cells. Since the pattern of MMP-26 expression mimicked that of ER-alpha, we searched the MMP-26 promoter region for a potential estrogen response element (ERE). A sequence at position -130 to -116 had high homology to the consensus sequence of an ERE. Based on these observations, we suggest that ER-alpha is involved in regulation of the MMP-26 gene.

CONCLUSIONS

MMP-26 mRNA is selectively localized in the epithelial compartment of normal, hyperplastic, and malignant endometrial tissue. Expression is high in normal and hyperplastic endometria, but is downregulated in the late part of the cycle and in malignant tumors. The expression pattern of MMP-26 mRNA mimics that of ER-alpha, and the promoter region of the MMP-26 gene has a potential ERE.

Progesterone regulation of activating protein-1 transcriptional activity: a possible mechanism of progesterone inhibition of endometrial cancer cell growth

The uterine endometrium and cancers derived from it are classic models of hormone action: estrogen promotes growth and progesterone inhibits proliferation and results in differentiation. We have now identified a major pathway through which progesterone causes these growth-limiting effects. Ligand-bound progesterone receptors modulate the composition and transcriptional activity of members of the activating protein-1 (AP-1) family, and in particular, c-Jun. First, a dominant negative form of c-Jun inhibits the constitutive growth of Hec50co cells in a manner similar to the effects of progesterone through progesterone B receptors. Second, progesterone inhibits the transcriptional activity of the AP-1 complex in reporter gene assays. Third, the DNA binding of AP-1 and the composition of the individual AP-1 factors on DNA is regulated by progesterone on electrophoretic mobility shift assays. Fourth, progesterone strongly inhibits total AP-1 as well as c-Jun recruitment to the cyclin D1 promoter, but enhances AP-1 occupancy on the p53 and p21 promoters, as shown by chromatin immunoprecipitation assays. The effects of progesterone on AP-1 DNA binding are confirmed to result in altered transcription of these AP-1 target genes by RT-PCR. These studies establish that modulation of AP-1 activity is a potential pathway of progesterone-induced growth inhibition in endometrial cancer cells.

DNA ploidy and S-phase fraction analyses of hyperplastic, atypical and cancerous endometrium using flow cytometry from paraffin-embedded tissues

Atypical hyperplasia of the endometrium is an entity that needs to be clearly distinguished from other florid hyperplastic states on the one hand and from well-differentiated adenocarcinomas on the other. This may at times be difficult on pure morphological grounds. In this study, DNA ploidy and S-phase fraction of hyperplastic, atypical and cancerous endometrium were evaluated using flow cytometry from paraffin-embedded tissues. In total, 72 cases (24 hyperplastic, 24 atypical and 24 adenocarcinomas) were selected. All hyperplastic endometria showed a diploid stemline, while 2/24 atypical hyperplasias showed aneuploid (Near-diploid) peaks. Both of these cases were severely atypical and one of these, on hysterectomy, showed early invasive carcinoma. There was no significant difference in mean S-phase fractions of hyperplastic vs. atypical endometria. DNA aneuploidy was significantly more common with much higher S-phase fractions in poorly and moderately differentiated carcinomas than in well-differentiated ones. It was concluded that aneuploid (near-diploid) peaks, if ever present in atypical hyperplasias, may indicate an aggressive disease/neoplastic transformation.

The effects of tamoxifen on proliferation and steroid receptor expression in postmenopausal endometrium

AIM

To study the effects of tamoxifen on the proliferation index and oestrogen receptor (ER) and progesterone receptor (PR) expression in postmenopausal endometrium.

METHODS

A total of 125 endometrial specimens of postmenopausal women, comprising benign endometria from tamoxifen users (n = 35) and non-users (n = 24), and endometrial cancer from tamoxifen users (n = 15) and non-users (n = 51), were immunohistochemically examined using MIB-1, anti-ER, and anti-PR antibodies in endometrial epithelium and stroma.

RESULTS

In benign endometrium the mean MIB-1 index in the epithelium was higher in tamoxifen users than in non-users (mean, 13% (SD, 13%) v mean, 2% (SD, 2%); p < 0.05), whereas in endometrial cancer the MIB-1 index was higher, but similar in tamoxifen users and non-users (mean, 32% (SD, 24%) and mean, 35% (SD, 18%)). The expression of ER was comparably high in benign epithelium from tamoxifen users and non-users (97% and 92%, respectively), but in endometrial cancer it was lower in tamoxifen users (60% and 88%; p < 0.05). The expression of PR in stromal cells was higher in tamoxifen users, both in benign (84% v 54%) and in malignant endometrium (33% v 10%; p < 0.05).

CONCLUSION

The proliferation index (as measured by MIB-1) in benign endometrial epithelium is higher in tamoxifen users than in non-users, and this might play a role in the reported higher incidence of endometrial cancer in postmenopausal tamoxifen users. The increased expression of PR in stroma from tamoxifen users with both benign and malignant endometrium demonstrates an additional oestrogenic effect of tamoxifen on the endometrial stroma.

Computerized image analysis of p53 and proliferating cell nuclear antigen expression in benign, hyperplastic, and malignant endometrium

CONTEXT

The endometrium is an intrinsically dynamic tissue with great capability for regeneration and proliferation; consequently, there is some overlap between features seen in benign, premalignant, and malignant lesions. This leads to marked intrabiopsy, interbiopsy, and interobserver variability.

OBJECTIVE

We studied the specificity and sensitivity of computerized image analysis of molecular markers to evaluate its potential use as a diagnostic tool.

DESIGN

Specimens from 100 patients were examined and the following histologic diagnoses were assigned: proliferative endometrium (n = 10), secretory endometrium (n = 10), endometrial hyperplasia (n = 40; 30 with no atypia, 10 with atypia), and carcinoma (n = 40; 20 endometrioid, 10 serous, and 10 clear cell). All cases were evaluated immunohistochemically for p53 and proliferating cell nuclear antigen (PCNA) expression. Computerized image analysis was performed with a CAS 200 digital analyzer.

RESULTS

Expression of p53 was found only in carcinomas (65%) and endometrial hyperplasia with atypia (30%). Expression of p53 was higher in the poor prognostic categories (serous carcinoma and clear cell carcinoma) than in endometrioid carcinoma. In endometrioid carcinoma, p53 expression correlated with grade. Proliferating cell nuclear antigen showed a similar pattern of results to p53 in the various carcinoma subtypes and endometrioid carcinoma grades. Endometrial hyperplasia PCNA values were the lowest among all the groups. Both carcinomas and proliferative endometrium showed higher glandular and stromal PCNA values, significantly different from endometrial hyperplasia with atypia. In proliferative endometrium, stromal PCNA was the highest among all of the groups. The p53 and PCNA results correlated with each other for carcinoma.

CONCLUSIONS

Computerized image analysis correlates well with the established morphologic groups of endometrial pathology and yields results consistent with previous studies. Owing to its higher degree of sensitivity, computerized image analysis is of potential use in cases of diagnostic dilemmas and can help objectively allocate the case in the correct category (e.g., proliferative endometrium vs. endometrial hyperplasia, endometrial hyperplasia with atypia vs. endometrioid carcinoma). It is particularly useful in the evaluation of stromal changes.

Correlation of proliferation indices, apoptosis, and related oncogene expression (bcl-2 and c-erbB-2) and p53 in proliferative, hyperplastic, and malignant endometrium

BACKGROUND

The various morphological groupings of endometrial pathology are often difficult to distinguish from each other. The endometrium is an actively proliferating tissue and there is an overlap in cell proliferation fraction (CPF) between benign proliferative endometrium (BPE) and endometrial carcinoma (EC). Apoptosis in benign cycling endometrium is related to the menstrual cycle. In this study we evaluated CPF, apoptosis, and oncogenes that relate to cell turnover (bcl-2, p53, and c-erbB-2) in the spectrum of endometrial pathology.

METHODS

We examined a total of 64 cases consisting of 10 cases of BPE, 18 cases of simple endometrial hyperplasia (SEH), 18 cases of complex hyperplasia (CEH; including eight cases with atypical hyperplasia), and 18 cases of EC, FIGO grade 1. CPF was measured by the mitotic index (MI) and by the percentage of Ki-67 positive nuclei (Ki-67 index). Apoptotic index (AI) was determined on hematoxylin and eosin sections.

RESULTS

MI was 2.48% in BPE, 0.65% in SEH, 0.6% in CEH, and 0.91% in EC (P < .00001). Ki-67 index was 38.44%, 16.4%, 23.25%, and 31.7% respectively (P < .00001). AI was 1.17%, 2.2%, 2.57%, and 3.31% respectively (P = .02). The AI/MI and AI/Ki-67 ratios were lowest in BPE and highest in SEH (P = .007). All cases of BPE, 84% of SEH cases, 77% of CEH cases, and 88% of EC cases displayed cytoplasmic and/or nuclear bcl-2 expression. Cytoplasmic bcl-2 expression increased from BPE to SEH, whereas it decreased in CEH and EC with emergence of only nuclear expression. Of the EC cases, 38.8% showed intense nuclear bcl-2 reactivity and a significantly higher Ki-67 index than cases with cytoplasmic expression (P = .01). No p53 or c-erbB-2 expression was seen in either BPE or EH. Of the EC cases, 50% were positive for p53 whereas 30% were positive for c-erbB-2. C-erbB-2-positive cases had a significantly higher Ki-67 index and AI than negative cases (P = .02). Cases of EC with p53 expression also had significantly higher AI (P = .01).

CONCLUSIONS

In actively proliferating tissues like endometrium, CPF does not correlate with progression to malignancy. In contrast, AI and derived AI/CPF ratios are better indicators of progression. The expression of p53, c-erbB-2, and nuclear bcl-2 in EC correlate with higher cell turnover indices (CPF and AI).

Neoplastic transformation of the endocervix associated with downregulation of lactoferrin expression

The incidence of cervical adenocarcinomas in young women over the last two decades has increased. Even with increasing knowledge of the role of human papillomavirus in the etiology of adenocarcinoma of the cervix, there is a paucity of data concerning the genetic and epigenetic factors that contribute to the histologic features and biologic behaviors of these tumors. Lactoferrin is a basic glycoprotein found in human milk, secondary granules of neutrophils, and many body secretions, and it has been associated with carcinogenesis of the endometrium, breast, and lymphoid systems. In this study, we examined the expression of lactoferrin in normal human endocervical epithelium and in cervical adenocarcinomas in relation to proliferative index, steroid receptor status, p53 protein expression, and apoptosis. Immunohistochemical and in situ studies demonstrated that lactoferrin protein and mRNA were strikingly downregulated upon neoplastic transformation of the endocervix as early as in adenocarcinoma in situ when compared with the prominent expression exhibited by the normal cervical epithelium. Furthermore, neoplastic transformation of endocervical epithelial cells was accompanied by a pronounced stimulation of proliferation and a substantial reduction in the expression of the estrogen and progesterone receptors and p53 but little or no change in the number of apoptotic cells. In conclusion, we identified lactoferrin as a novel cancer-specific marker of endocervical adenocarcinomas that may be useful in the early detection of the disease, prediction of prognosis, and the development of new therapeutic modalities.

Treatment of endometrial hyperplasias with gonadotropin-releasing hormone agonists: pathological, clinical, morphometric, and DNA-cytometric data

On the basis of the recently reported observation that gonadotropin-releasing hormone agonists (GnRH-a) can affect endometrial cell proliferation, both indirectly, through the hormonal axis, and directly, by acting on the GnRH-a receptors, we investigated how far GnRH-a can be used as a new treatment mode for endometrial hyperplasias. Forty-two women, aged 28-60 years, with histologically confirmed simple (n = 30) or complex (n = 12, 2 with atypias) hyperplasia of the endometrium were involved in the study. According to the protocol they were treated for 6 months with GnRH-a (leuprolide acetate or triptorelin), and each patient underwent uterine curettage in the third and the sixth month of treatment, and 6 and at least 12 months after cessation of the treatment, for histological examination and morphometric and DNA-cytometric evaluation of the endometrium (mean pathological follow-up, 19.2 months; mean clinical follow-up, 30.7 months). During treatment, most of the women first revealed endometrial atrophy, and, after cessation of the treatment, again an atrophic or mainly functional endometrium; in 7 women, all with initial diagnosis of simple hyperplasia, the endometrial hyperplasia reappeared, which led in all 7 cases to hysterectomy. The mean values of almost all morphometric and DNA-cytometric parameters during and after treatment showed statistically significant changes in relation to pretreatment values, indicating a decrease in the proliferative activity of the endometrial cells; the GnRH-a antiproliferative effect was still active for a long time after cessation of the therapy. Our results, based for the first time not only on histological but also on serial nuclear morphometric and DNA-cytometric examinations of the endometrial cells and on the longest follow-up time, support the view that in cases of endometrial hyperplasia, especially of complex type, the use of GnRH agonists, which decrease the proliferative tendency of endometrial cells, could represent an alternative conservative therapeutic approach, which, however, requires close monitoring of the endometrium.

Potential criteria for cohort selection in chemoprevention trials of uterine adenocarcinoma

Women at risk of uterine cancer include those with one or more of the following characteristics: obesity, nulliparity, late menopause, diabetes mellitus, prolonged unopposed estrogen use, and tamoxifen therapy. Risk is additionally increased by the presence of endometrial hyperplasia. The incorporation of biomarkers into the selection criteria of cohort groups at risk for developing endometrial cancer offers an innovative approach to the clinical design of chemoprevention trials of endometrial adenocarcinoma. Biomarkers that may be useful in cohort selection include nuclear morphometry, specific genetic abnormalities, and markers of proliferation and differentiation.