Proliferative activity in postmenopausal endometrium: the lurking potential for giving rise to an endometrial adenocarcinoma

Endometrial safety of low-dose vaginal estrogens

ABSTRACT

It is estimated that up to 50% to 90% of postmenopausal women may experience genitourinary syndrome of menopause (GSM), which may have a detrimental impact on quality of life. One of the most effective modes of treatment of GSM is low-dose vaginal estrogens. Numerous studies have addressed the safety of these estrogens using endometrial biopsy and/or endometrial thickness on ultrasound. Based on these studies, the consensus is that low-dose vaginal estrogens do not substantially increase the risk of endometrial hyperplasia or cancer; however, the data are severely limited by short duration of follow-up. Although long-term trials are warranted, they are difficult to carry out, costly, and will not yield data for years. More immediate information regarding endometrial safety may be obtained from studies measuring endometrial tissue and serum concentrations of estradiol, estrone, and relevant equine estrogens after administration of different estrogen formulations and doses. This would allow us to understand better the metabolism of estrogens by the vagina and endometrium, and how much estrogen is reaching the endometrium. Here, we discuss metabolism, receptor binding, and signaling of estrogens in vaginal and endometrial tissue, and summarize the existing studies on the endometrial impact of low-dose vaginal estrogen treatment in postmenopausal women.

Long-term outcome of postmenopausal women with proliferative endometrium on endometrial sampling

BACKGROUND

Proliferative endometrium has been reported in 15% of endometrial biopsies of women aged 50 years and older. Contrary to endometrial hyperplasia, proliferative endometrium has not been associated with the risk of endometrial cancer.

OBJECTIVE

This study aimed to report on the long-term outcome of postmenopausal women who received a diagnosis of proliferative endometrium.

STUDY DESIGN

This is a retrospective cohort study of 1808 women aged 55 years and older who underwent endometrial sampling between January 1997 and December 2008. Outcome data were available through February 2018. Women with a proliferative endometrium were compared with those with an atrophic endometrium for future development of endometrial hyperplasia or cancer. A subanalysis was performed for those who presented with postmenopausal bleeding. Uni- and multivariable logistic regression analyses were used to assess for confounders.

RESULTS

In this study, 297 women (16.4%) received a diagnosis of proliferative endometrium. Furthermore, 962 women met the inclusion criteria. Among those women, 278 had a proliferative endometrium, and 684 had an atrophic endometrium. Women with a proliferative endometrium were younger (61.2 vs 64.5 years; P<.0001) and had a higher body mass index (33.9 vs 30.6 kg/m²; P<.0001). More African American women had a proliferative endometrium. Both groups had a similar length of surveillance (11.9 vs 11.5 years; P=.27). Women with a proliferative endometrium had a higher risk of developing endometrial hyperplasia or cancer (11.9% vs 2.9%; P<.0001), any endometrial cancer (5.8% vs 1.8%; P=.002), atypical endometrial hyperplasia (2.2% vs 0.4%; P=.02), and nonatypical endometrial hyperplasia (2.0% vs 0.7%; P=.001). The risk of developing endometrial cancer and endometrial hyperplasia remained similar after excluding cases on hormonal replacement therapy (12.2% vs 3%; P=.001). On logistic regression analysis, proliferative endometrium histology (odds ratio, 3.89; 95% confidence interval, 2.03-7.49; P<.0001), age >60 years (odds ratio, 1.98; 95% confidence interval, 1.03-3.82; P=.04), and body mass index >35 kg/m² (odds ratio, 2.3; 95% confidence interval, 1.09-4.83; P<.0001) remained significant risk factors for progression to cancer.

CONCLUSION

One of the 6 postmenopausal women who underwent endometrial sampling had a proliferative endometrium. Furthermore, 11.9% of women developed endometrial hyperplasia or cancer, a 4-fold greater incidence than women with an atrophic endometrium. The findings of this study suggest that long-term monitoring is warranted for women with postmenopausal bleeding and a proliferative endometrium histology. Further studies are needed to examine if a treatment is required to negate the risk of unopposed estrogen.

Proliferation in Postmenopausal Endometrial Polyps-A Potential for Malignant Transformation

Background and objectives: Endometrial polyps in asymptomatic postmenopausal women are often incidentally found, yet only 1.51% of them are malignant. Their potential for malignant transformation has not been adequately addressed. The aim of this study was to investigate the proliferation within endometrial polyps as one of the indicators of their malignization potential in asymptomatic postmenopausal women. Materials and Methods: Immunohistochemical studies of Ki-67 were performed. Cases included 52 benign postmenopausal polyps, 19 endometrioid carcinoma with coexisting benign polyps, 12 polyps with foci of carcinoma and 4 cases of polyps, which later developed carcinoma. The control group included 31 atrophic endometria and 32 benign premenopausal polyps. Ki-67 was scored in either 10 or 20 “hot spot” fields, as percentage of positively stained cells. Results: The median epithelial Ki-67 score in postmenopausal benign polyps (4.7%) was significantly higher than in atrophic endometria (2.41%, p < 0.0001) and significantly lower than in premenopausal benign polyps (11.4%, p = 0.003) and endometrial cancer (8.3%, p < 0.0001). Where endometrial polyps were found in association with endometrial carcinoma, Ki-67 was significantly higher in cancer (p < 0.0001). No significant difference was found between Ki-67 scores of cancer focus and of the polyps tissue itself, respectively 2.8% and 4.55%, p = 0.37. Ki-67 expression, where polyps were resected and women later developed cancer, was not significantly different (p = 0.199). Conclusion: Polyps from asymptomatic postmenopausal women showed significantly more proliferation in both epithelial and stromal components than inactive atrophic endometria but less than premenopausal benign polyps and/or endometrial cancer. Benign postmenopausal endometrial polyps exhibit low proliferative activity, suggesting low malignant potential and may not require resection in asymptomatic women.

Molecular profiles of benign and (pre)malignant endometrial lesions

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

Insulin/IGF and sex hormone axes in human endometrium and associations with endometrial cancer risk factors

PURPOSE

Experimental and observational data link insulin, insulin-like growth factor (IGF), and estrogens to endometrial tumorigenesis. However, there are limited data regarding insulin/IGF and sex hormone axes protein and gene expression in normal endometrial tissues, and very few studies have examined the impact of endometrial cancer risk factors on endometrial tissue biology.

METHODS

We evaluated endometrial tissues from 77 premenopausal and 30 postmenopausal women who underwent hysterectomy for benign indications and had provided epidemiological data. Endometrial tissue mRNA and protein levels were measured using quantitative real-time PCR and immunohistochemistry, respectively.

RESULTS

In postmenopausal women, we observed higher levels of phosphorylated IGF-I/insulin receptor (pIGF1R/pIR) in diabetic versus non-diabetic women (p value =0.02), while women who reported regular nonsteroidal anti-inflammatory drug use versus no use had higher levels of insulin and progesterone receptors (both p values ≤0.03). We also noted differences in pIGF1R/pIR staining with OC use (postmenopausal women only), and the proportion of estrogen receptor-positive tissues varied by the number of live births and PTEN status (premenopausal only) (p values ≤0.04). Compared to premenopausal proliferative phase women, postmenopausal women exhibited lower mRNA levels of IGF1, but higher IGFBP1 and IGFBP3 expression (all p values ≤0.004), and higher protein levels of the receptors for estrogen, insulin, and IGF-I (all p values ≤0.02). Conversely, pIGF1R/pIR levels were higher in premenopausal proliferative phase versus postmenopausal endometrium (p value =0.01).

CONCLUSIONS

These results highlight links between endometrial cancer risk factors and mechanistic factors that may contribute to early events in the multistage process of endometrial carcinogenesis.

Androgen receptors are acquired by healthy postmenopausal endometrial epithelium and their subsequent loss in endometrial cancer is associated with poor survival

BACKGROUND

Endometrial cancer (EC) is a hormone-driven disease, and androgen receptor (AR) expression in high-grade EC (HGEC) and metastatic EC has not yet been described.

METHODS

The expression pattern and prognostic value of AR in relation to oestrogen (ERα and ERβ) and progesterone (PR) receptors, and the proliferation marker Ki67 in all EC subtypes (n = 85) were compared with that of healthy and hyperplastic endometrium, using immunohistochemisty and qPCR.

RESULTS

Compared with proliferative endometrium, postmenopausal endometrtial epithelium showed significantly higher expression of AR (P < 0.001) and ERα (P = 0.035), which persisted in hyperplastic epithelium and in low-grade EC (LGEC). High-grade EC showed a significant loss of AR (P < 0.0001), PR (P < 0.0001) and ERβ (P < 0.035) compared with LGEC, whilst maintaining weak to moderate ERα. Unlike PR, AR expression in metastatic lesions was significantly (P = 0.039) higher than that in primary tumours. Androgen receptor expression correlated with favourable clinicopathological features and a lower proliferation index. Loss of AR, with/without the loss of PR was associated with a significantly lower disease-free survival (P < 0.0001, P < 0.0001, respectively).

CONCLUSIONS

Postmenopausal endometrial epithelium acquires AR whilst preserving other steroid hormone receptors. Loss of AR, PR with retention of ERα and ERβ may promote the unrestrained growth of HGEC. Androgen receptor may therefore be a clinically relevant prognostic indicator and a potential therapeutic target in EC.

Spontaneous Reproductive Tract Lesions in Aged Captive Chimpanzees

Chimpanzees (Pan troglodytes) have served as an important model for studies of reproductive diseases and aging-related disorders in humans. However, limited information is available about spontaneously occurring reproductive tract lesions in aging chimpanzees. In this article, the authors present histopathologic descriptions of lesions identified in the reproductive tract, including the mammary gland, of 33 female and 34 male aged chimpanzees from 3 captive populations. The most common findings in female chimpanzees were ovarian atrophy, uterine leiomyoma, adenomyosis, and endometrial atrophy. The most common findings in male chimpanzees were seminiferous tubule degeneration and lymphocytic infiltrates in the prostate gland. Other less common lesions included an ovarian granulosa cell tumor, cystic endometrial hyperplasia, an endometrial polyp, uterine artery hypertrophy and mineralization, atrophic vaginitis, mammary gland inflammation, prostatic epithelial hyperplasia, dilated seminal vesicles, a sperm granuloma, and lymphocytic infiltrates in the epididymis. The findings in this study closely mimic changes described in the reproductive tract of aged humans, with the exception of a lack of malignant changes observed in the mammary gland and prostate gland.

Akt/protein B and estradiol receptor alpha expressions in postmenopausal endometrium

OBJECTIVE

Estrogen receptor interacts in several types of cells with phosphatidyl-inositol 3-kinase/Akt pathway regulating cell survival and apoptosis. No data are available of the Akt/PKB signaling and its role in the endometrial homeostasis of the postmenopausal uterus. The aim of the present investigation was to study the Akt/protein kinase B signaling in tissue samples retrieved from postmenopausal endometrium of the human uterus with parallel observation of the changes of the expression and phosphorylation of ERalpha.

STUDY DESIGN

Sixty disease-free postmenopausal women were enrolled in the study. Endometrial tissue samples were obtained from diagnostic curettage or direct from the uterus after hysterectomy done for benign uterine lesions other than endometrial disease. For comparison, the studied parameters were also analyzed in endometrial samples of women with regular menstrual cycles (n=16). In each individual tissue sample the expression and phosphorylation of ERalpha, Akt, and cyclin D1 was analyzed by Western blotting.

RESULTS

The level of Akt protein did not show significant change, however, the activation of Akt proteins and the expression of ERalpha increased parallel with serum estrogen (E2) levels, suggesting the role of E2 in Akt activation and ERalpha expression. The level of pERalpha(Ser167) changed parallel with pAkt(Ser473) levels. Significant correlation was found between the changes of pERalpha and ERalpha (r=0.650399, p<0.005), and in that of pERalpha and pAkt (r=0.639643, p<0.007), respectively. The expression of cyclin D1 was increased in samples with elevated pAkt levels.

CONCLUSION

The results are indicating that the postmenopausal endometrium responds to E2 by both genomic and nongenomic mechanism. The interaction between ERalpha and Akt plays crucial role in the regulation of proliferative activity in postmenopausal endometrium.

Expression of sonic hedgehog signaling molecules in normal, hyperplastic and carcinomatous endometrium

The aim of the present study was to determine the expression profile of the hedgehog (Hh) signaling molecules in normal, hyperplastic, and carcinomatous uterine endometrium. For this purpose, 271 endometrial tissue samples, (62 of normal endometrium, 127 of endometrial hyperplasias, and 82 endometrial adenocarcinomas) were studied using antibodies recognizing Hh-related signaling proteins, such as, sonic hedgehog (Shh), Patched (PTCH), Smoothened (Smo), Suppressor of fused [Su(Fu)], Gli-1, Gli-2, and Gli-3 by immunohistochemistry. The mRNA expression of these molecules was also assessed on reverse transcription-polymerase chain reaction. In the normal endometrium, the expression of Hh signaling molecules was generally downregulated except for Su(Fu), Gli-2, and Shh. In particular, the expression of both PTCH and Smo was very low or almost absent. Overall expression of Hh signaling molecules increased in hyperplastic endometrium; in particular, PTCH and Smo were significantly highly expressed in complex and atypical hyperplasia. In carcinoma samples extensive alterations were observed in the expression pattern of the signaling molecules. Nuclear Gli-2, cytoplasmic Gli-3, and Su(Fu) were overexpressed, whereas Shh, PTCH, and Smo expression were significantly reduced compared with the hyperplastic endometrium. The results suggest that the alteration of Hh signaling may be implicated in tumorigenesis of the endometrium.

Effect of hormone replacement therapy on postmenopausal endometrial bleeding

The aim of the study was to determine the effect of postmenopausal hormone replacement therapy (HRT) (treatment using estrogen only and sequential and continuous combined estrogen-progestogen treatment) on endometrial bleeding and histological changes of the endometrium. In a six-year period (2000-2005), 5893 patients were given care and the incidence of postmenopausal uterine bleeding was detected in groups of patients having and not having received hormonal treatment at the Menopause Outpatient Unit of the authors' department. In the case of bleeding, fractioned abrasion was performed and the samples were analyzed histologically. Among the postmenopausal patients who had not been given hormonal treatment, the incidence of bleeding episodes was significantly higher as among those having received hormonal treatment. In the samples, findings of proliferative endometrium occurred significantly more often in case of non-treated patients and those treated with sequential combined hormone therapy compared to patients receiving continuous combined hormone therapy. Although it was statistically not significant, hyperplasia simplex and complex together showed a tendency of reduced incidence in patients medicated by continuous combined treatment. These findings suggest that continuous combined hormonal treatment started at the right time (even before the menopause) may reduce the chances of the development of hyperplasia. A significantly higher incidence of hyperplasia was noted in patients using estrogen treatment only. It is possible that unopposed estrogen treatment further engraves an already diagnosed endometrial hyperplasia. In the group having received hormonal treatment, no complex hyperplasia accompanied by atypia occurred, only hyperplasia simplex was diagnosed in these cases. As a result of continuous reliance on combined preparations, the endometrium had become atrophied, therefore the chance of hyperplasia-related changes and of bleeding as a side effect decreased significantly. According to the authors' experience, hormonal treatment does not pose a risk to the development of endometrial carcinoma; on the contrary, continuous combined preparations appear to reduce the risk of hyperplasia and, indirectly, the chances of the development of adenocarcinoma.

Randomized Dose-Ranging Trial of Tamoxifen at Low Doses in Hormone Replacement Therapy Users

Purpose

The combination of hormone replacement therapy (HRT) and low-dose tamoxifen may retain the benefits while reducing the risks of either agent. We assessed the optimal biologic dose and schedule of tamoxifen in HRT users using surrogate end point biomarkers and menopausal symptoms.

Subjects and Methods

Two hundred ten current or de novo HRT users were randomly assigned to one of the following four arms: tamoxifen 1 mg/day and placebo/week, placebo/day and tamoxifen 10 mg/week, tamoxifen 5 mg/day and placebo/week, or both placebos for 12 months. The primary end point was the change of plasma insulinlike growth factor 1 (IGF-I) through 12 months, and secondary end points were IGF-I/IGF binding protein-3 (IGFBP-3) ratio, fibrinogen, antithrombin III, C reactive protein, C-telopeptide, mammographic percent density, and endometrial thickness. Endometrial proliferation was assessed by Pipelle biopsy in superficial, deep glandular, and stromal compartments after 12 months.

Results

Compared with placebo, IGF-I declined in all tamoxifen arms (P = .005), with a greater change on 5 mg/day (P = .019 v 10 mg/week or 1 mg/day). Tamoxifen increased IGFBP-3 and lowered antithrombin-III, C reactive protein, and mammographic density, with greater effects of 5 mg/day. Tamoxifen increased endometrial thickness but not Ki-67 expression, which was lower on 5 mg/day among the three doses. Menopausal symptoms were not significantly worsened by tamoxifen.

Conclusion

Doses of tamoxifen ≤ 5 mg/day modulate favorably biomarkers of breast carcinogenesis and cardiovascular risk in HRT users with no increase of endometrial proliferation and menopausal symptoms. A dose of 5 mg/day was the most effective and has been selected for a phase III trial in HRT users.

The effect of postmenopausal hormone replacement therapy on endometrial bleeding

Cékitűzés: A vizsgálat célja meghatározni a postmenopausalis hormonterápia (kizárólagos ösztrogén-, szekvenciális és folyamatosan kombinált ösztrogén-progesztogén kezelés) hatását az endometrialis vérzésre és a méhnyálkahártya szövettani átalakulására. Beteganyag: Szerzők klinikájának Menopauza Ambulanciáján ötéves időszakban (2000–2005) 5893 beteget gondoztak, és vizsgálták a postmenopausalis méhvérzések előfordulását a hormonterápiában részesültek és nem részesültek csoportjában. Vérzés esetén mindig frakcionált abrasiót végeztek, és a mintákat szövettanilag feldolgozták. Eredmények: A postmenopausában lévő betegek hormonkezelésben nem részesítettek csoportjában több mint kétszer több vérzés fordult elő, mint a hormonkezelésben részesültek között. Anyagukban a proliferatiós és a hyperplasiás endometrium-leletek elsősorban a nem kezelt páciensek közül kerültek ki, ami amellett szól, hogy a megfelelő időben, akár már a menopausa előtt megkezdett hormonkezelés csökkentheti a hyperplasia és ezáltal közvetve az adenocarcinoma kialakulásának az esélyét. A kizárólag ösztrogént alkalmazó betegekben gyakoribb volt a hyperplasia. Elképzelhetőnek tartják, hogy az ellensúlyozatlan ösztrogénkezelés a már meglévő endometrium-hyperplasiát tovább súlyosbíthatja. A hormonkezeltek csoportjában atípiával járó komplex hyperplasia nem, csak simplex hyperplasia fordult elő. A folyamatosan kombinált készítmények alkalmazása mellett az esetek döntő részében a méhnyálkahártya atrófizálódott, így lényegesen csökkent a hyperplasiával járó eltérések s a mellékhatásként jelentkező vérzés esélye. A hormonkezeltek között gyakoribb volt az endometrium-polip, és nem tudják megmagyarázni, de a cervicalis polypusok aránya is. Következtetés: A szerzők tapasztalata szerint a hormonkezelés nem rizikótényezője az endometrium-karcinómának, hanem a kombinált készítmények a hyperplasia és ezen keresztül az adenocarcinoma eredeti esélyét csökkentik.

The impact of delay in cryo-fixation on biomarkers of Src tyrosine kinase activity in human breast and bladder cancers

Demonstration of pharmacodynamic activity of new, targeted cancer drugs in tumour tissue is potentially important in guiding early drug development. However, delays between tumour sampling and sample fixation may result in variability of pharmacodynamic biomarkers. The aim of this study, was to assess the impact of delays in fixation on biomarkers of Src kinase activity. A total of 20 patients with locally advanced breast cancer and 5 with early bladder cancer had multiple tissue samples taken which were fixed at documented time points up to 60 min after biopsy. These were examined to determine if the amount of Paxillin, phospho-Paxillin, phospho-focal adhesion kinase (FAK) and total phospho-Tyrosine changed over time, using a quantitative lysate immunoassay. In breast cancer, there was an increase in the amount of phospho-Paxillin (60% per h; P = 0.019) up to 60 min after biopsy. The amount of total Paxillin decreased (28% per h; P = 0.034) over the same time course. In early bladder cancer, no changes were noted in any endpoints up to 45 min. Standardisation of the time taken between biopsy and fixation may be critical, particularly in studies using phosphorylated protein biomarkers.

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

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

Putative stem cell activity of human endometrial epithelial and stromal cells during the menstrual cycle

OBJECTIVE

To determine whether menstrual cycle stage or activity has an effect on the clonogenic activity of human endometrial epithelial and stromal cells.

DESIGN

Clonal analysis of human endometrial epithelial and stromal cells derived from full-thickness endometrium.

SETTING

University research laboratory.

PATIENT(S)

Twenty-six women of varying age and race undergoing hysterectomy for nonendometrial pathologies.

INTERVENTION(S)

Full-thickness human endometrial tissue was dissociated into single cells. Epithelial and stromal cells were separated using magnetic beads, and cloning assays were performed in serum-containing or growth factor-supplemented serum-free medium.

MAIN OUTCOME MEASURE(S)

Clonogenic activity of epithelial and stromal cells.

RESULT(S)

Clonogenicity of epithelial and stromal cells did not vary significantly between proliferative, secretory, and inactive endometrium. However, epithelial and stromal cells did show a trend for greater numbers of clonogenic cells in secretory and proliferative endometrium respectively. A large variation between samples was observed, which may have masked any significant differences.

CONCLUSION(S)

We found that clonogenicity does not vary from the proliferative to secretory stage of the menstrual cycle, or between active, cycling and inactive endometrium for both epithelial and stromal cells. We have demonstrated for the first time that inactive endometrium contains clonogenic epithelial and stromal cells.

Endometrial adenocarcinoma: beliefs and scepticism

The incidence of endometrial adenocarcinoma is high in North America and northern Europe, and low in Asia and Africa. This variance in frequency rates occurred in the late 1970s and its real cause has remained in question since. There is a widespread belief that endometrial adenocarcinomas associated with endometrial hyperplasia have a much better prognosis than those related to endometrial atrophy. This view is, in general terms, true but only because a high proportion of tumors arising from an atrophic endometrium are of serous/papillary, clear cell, or Grade 2-3 endometrioid carcinomas, in contrast to those developing from a hyperplastic endometrium, which are nearly all G1 endometrioid adenocarcinomas. These adenocarcinomas have, however, an excellent prognosis, no matter whether they are related to hyperplasia or atrophy, and taxonomically they form a single tumor group. In this regard, it is most reasonable to separate endometrial carcinomas into low- and high-grade tumors. The first are formed solely of G1 or "authentic" endometrioid adenocarcinomas, i.e., endometrioid neoplasms composed in their entirety of glandular elements without having traces of nonsquamous solid components. The high-grade tumors are formed of both endometrioid Grade 2-3 adenocarcinomas and nonendometrioid carcinomas-all of particularly aggressive behavior. The question of grading endometrioid adenocarcinomas in a precise and reproducible way becomes obvious. It is also believed that endometrial adenocarcinomas associated with endometrial hyperplasia are estrogen-primed, while those related to endometrial atrophy are deprived of hormonal stimulation. However, as we have shown in this laboratory recently, estrogen stimulation may be very common in endometrial neoplasms developing in an atrophic endometrium. For indeed most, if not all, postmenopausal atrophic endometria harboring adenocarcinomas contain actively proliferating glands, with high Ki-67 proliferation index, high epidermal growth factor receptor (EGFR) activity, high microvessel density (MVD), and rich in estrogen and progesterone receptors (ER and PR), indicative of a continuous low-level estrogenic stimulation. That there is a number of endometrial carcinomas that tend to develop in a milieu of antiestrogenic domination, following treatment for breast carcinoma, this may well represent a form of breast-endometrial hereditary disease and, certainly, merits further investigation.