Inhibin (10.7 kD prostatic peptide) in normal, hyperplastic, and malignant human endometria: an immunohistochemical study.

The expression of inhibin, a 10.7 kD follicle-stimulating hormone (FSH)-suppressing prostatic peptide of 94 amino acids, was investigated in normal human endometrium, endometrial hyperplasia, and adenocarcinoma, employing the avidin-biotin immunoperoxidase technique. The antiserum used was raised in rabbits against prostatic inhibin isolated from human seminal plasma. The study included 15 well differentiated, 32 moderately differentiated, and 21 poorly differentiated endometrial adenocarcinomas; 26 simple, five complex, and two complex atypical endometrial hyperplasias; and, for comparison, 25 normal proliferative and 30 normal secretory endometria. In malignant and hyperplastic endometrial tissues, inhibin was localized in the epithelial cytoplasm of endometrial glands while the stroma showed weak reactivity. On the other hand, inhibin was undetectable in the early proliferative phase, but was present on the luminal border of the glandular epithelium in the mid- and late proliferative phases. Secretory endometrium displayed strong inhibin reactivity in the cytoplasm of glandular epithelium and in the stroma. The increased inhibin reactivity in secretory endometrium as compared with the proliferative phase is indicative of a functional role for inhibin in the uterus. In addition, its localization in proliferative, hyperplastic, and malignant endometria suggests a possible regulatory role for inhibin in endometrial proliferation and growth.     

Immunodetection of sialyl-Tn antigen in normal,hyperplastic and cancerous tissues of the uterine endometrium

Summary The expression of sialyl-Tn antigen (STn) in normal, hyperplastic and neoplastic tissues of the uterine endometrium was examined by immunoperoxidase staining of formalin-fixed, paraffin-embedded samples using the monoclonal antibody TKH-2, directed toward the STn structure (NeuAc 2–6GalNac 1-O-serine or threonine). STn was expressed in 13 of 18 normal postovulatory endometria with an increasing staining intensity and incidence in the late secretory phase. It was consistently absent in 10 proliferative endometria. None of 5 cystic, 4 adenomatous or 12 atypical hyperplasias expressed STn, but areas of severe cytological atypia in 3 atypical hyperplasias showed faint expression. STn expression was detected in 36 of 43 adenocarcinomas. Although the extent of staining varied from a few to most of the cancer cells, general staining was observed throughout the cytoplasm of cancer cells with increased staining of the luminal surface and frequent positive staining of intraluminal mucin. Thus, it is clear that STn is selectively expressed in cancer cells and shows restricted expression in normal and hyperplastic endometrial tissues. STn may be an early marker of malignant transformation and has potential for use as a diagnostic aid in the surgical pathology of the uterine endometrium.     

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.     

Immunohistochemical analysis of CD44s and CD44v6 in endometriosis and adenomyosis : comparison with normal, hyperplastic, and malignant endometrium.

The expression patterns of CD44s and CD44v6 were immunohistochemically compared with those of normal, hyperplastic and malignant endometrium. In normal endometria (n=37), endometrioses (n=46) and adenomyoses (n=20), the surface and glandular epithelial cells were negative for CD44s and CD44v6 in a proliferative pattern and positive in a secretory pattern, whereas the stroma was only positive for CD44s in both proliferative and secretory patterns. The endometrial hyperplasia (4 simple and 9 complex) had the identical patterns with normal proliferative phase of endometrium. Only one case showing complex hyperplasia with atypia was focally positive for CD44s and CD44v6 in glandular epithelia. CD44s and CD44v6 were positive in all endometrial adenocarcinomas (13), except one CD44s-negative case. In summary, the expressions of CD44s and CD44v6 in endometriosis and adenomyosis recapitulated those of normal cyclic endometrium. The expression patterns in endometrial hyperplasia were similar to those in normal proliferative endometrium, whereas the endometrial adenocarcinoma showed abnormal expressions for CD44s and CD44v6. Thus it was considered that the ectopic endometrium in endometriosis and adenomyosis was not aberrant as in endometrial carcinoma on the aspects of immunohistochemical expressions of CD44s and CD44v6.     

UbcH10 expression in benign, hyperplastic, and malignant endometrial curetted materials: a tissue microarray study

The aim of this study was to investigate the role of UbcH10 expression in the differential diagnosis of benign, hyperplastic, and malignant endometrial tissues and also the relationship of UbcH10 with the clinicopathologic parameters of malignant cases. A tissue microarray was performed for 81 endometrial curettage biopsies, which histological diagnosis had demonstrated to be 13 cases of proliferative endometrium, 7 cases of disordered proliferative endometrium, 5 cases of complex atypical hyperplasia, 24 cases of nonatypical hyperplasia, and 32 cases of endometrioid adenocarcinoma. Expression of UbcH10 was assessed by immunohistochemistry. When groups were compared according to UbcH10 percentages and scores, a statistically significant difference was found only between the carcinoma group and the other groups, except the complex atypical hyperplasia group (P < .05). In the malignant group, UbcH10 percentages and scores were only significantly related to age. There was no significant association between UbcH10 expression and tumor grade and stage. Overexpression of UbcH10 may be a useful indicator of endometrial carcinoma. UbcH10 also deserves further evaluation in the detection of prognostic mean and also for its role in endometrial carcinogenesis.     

Temporal and site-specific expression of transforming growth factor- beta4 in human endometrium

We recently identified a novel member of the transforming growth factor (TGF)-beta superfamily and showed that this gene, designated as endometrial bleeding associated factor (ebaf), or TGFbeta4, has a unique expression pattern in human endometrium. By Northern blot analysis, we showed that this gene was expressed in human endometrium during the late secretory and menstrual phases and was absent in proliferative, early and mid-secretory endometria. In this report, we show by in-situ hybridization that the mRNA of the TGF-beta4 is not expressed in the proliferative endometria. On the other hand, focal expression of the TGFbeta4 mRNA first appears in some endometrial glands in the mid-secretory phase. The TGFbeta4 mRNA is strongly expressed in the endometrial stroma during the late secretory and menstrual phases of the cycle. We raised a polyclonal rabbit antiserum against a peptide at the C terminal of the protein. Western blot analysis using affinity purified antiserum shows that the TGFbeta4 precursor detected in the endometrium as well as placenta is 41 kDa. Bands in the range of 45-51 kDa are also present in human endometrium, more predominantly during the late secretory phase. Immunohistochemical staining shows a low level of immunoreactivity for TGFbeta4 in the early, mid- and late proliferative and early and mid-secretory endometria. A strong immunoreactivity for TGFbeta4 is present in the stroma and to lesser extent in the endometrial glands in late secretory and menstrual endometria. The specificity of staining was shown by neutralizing the activity of the antibody with the synthetic peptide used for raising the antibody and by omitting the antibody. The findings show that TGFbeta4, both at the mRNA and protein levels, exhibits temporal and site specific expression in human endometrium.      

Thymidine phosphorylase expression in normal and hyperplastic endometrium

AIMS: To investigate the expression of thymidine phosphorylase (TP), a known angiogenic factor for endothelial cells, in normally cycling endometrium and various forms of endometrial hyperplasia. METHODS: TP expression was assessed with the P-GF.44C monoclonal antibody, using the alkaline phosphatase anti-alkaline phosphatase method. Ninety two normal and hyperplastic endometria were studied. RESULTS: In normal proliferative endometrium, TP is found exclusively in the basal layer and the inner third of the functionalis; expression is cytoplasmic in glandular epithelium and nuclear in stromal cells. It is invariably patchy. This immunohistochemical picture remains almost unaltered during the early and mid secretory phase of the normal menstrual cycle but, most impressively, TP is expressed uniformly in the epithelium of all endometrial glands towards the end of the cycle. At this stage, expression is mixed nuclear/cytoplasmic and there is very little stromal nuclear staining. In simple endometrial hyperplasia, the staining pattern for TP is identical to normal proliferative endometrium, with a distribution that is usually limited to a few rather weakly proliferating glands and to the adjacent periglandular stroma of the deep endometrium. The distribution is more extensive in complex and atypical endometrial hyperplasias, where a mixed nuclear/cytoplasmic pattern usually prevails over the pure cytoplasmic reaction. CONCLUSIONS: TP is expressed consistently in normal and hyperplastic endometrium, suggesting a role in physiological and pathological angiogenesis. In normal endometrium, TP has a definite pattern of distribution, which is dependent on the phase of the menstrual cycle, whereas in all forms of endometrial hyperplasia the enzyme is randomly distributed and lacks an orderly pattern.     

beta 1C Integrin expression in human endometrial proliferative diseases

Integrins are ubiquitous cell adhesion molecules that are involved in maintaining normal tissue morphology and have been implicated in the aggressive behavior of several malignancies. beta 1C integrin is an alternatively spliced variant of the beta 1A integrin subunit that, at variance with beta 1A, inhibits epithelial cell proliferation. beta 1C integrin is expressed in non-proliferative, benign prostatic epithelium and is down-regulated in prostatic adenocarcinoma. In the current study, we examined beta 1C expression at mRNA and protein levels in 18 endometrial adenocarcinoma and in 20 endometrial hyperplastic tissues, using Northern and Western blotting analysis and immunohistochemistry. The pattern of integrin expression was compared to that of the endometrium of 14 normal cycling women. The results of this study document inhibited beta 1C integrin expression in endometrial adenocarcinoma, both at the mRNA and protein levels, at variance with significantly up-regulated beta 1C mRNA expression in endometrial hyperplasia, in comparison with normal proliferative endometria. Our data suggest a key role of the regulation of beta 1C integrin expression in the pathogenesis of endometrial proliferative diseases: beta 1C integrin may act as growth modulator in cancer cells, playing a role in downstream intracellular signaling.     

ANGIOGENESIS IN NORMAL,HYPERPLASTIC, AND NEOPLASTIC ENDOMETRIUM

The purpose of this study was to quantify vascular density in the stroma of normal, hyperplastic, and neoplastic endometria and to explore its relationship to other prognostic features of endometrioid adenocarcinoma. Curettage specimens of proliferative and mid-secretory endometrium; simple, complex, and atypical endometrial hyperplasia; and grade I endometrioid adenocarcinoma were stained with Factor VIII-related antigen. The number of vessels per mm² of stroma was calculated for each case. The stroma of mid-secretory and hyperplastic endometrium was more vascular than that of proliferative endometrium. The stroma of adenocarcinoma, though reduced in proportion to the epithelium, was significantly more vascular than that of normal or hyperplastic endometrium. Stromal vascular density was not related to the depth of invasion, the presence of lymphovascular space permeation, or the state of the adjacent endometrium, whether atrophic or hyperplastic.     

Patterns of episialin/MUC1 expression in endometrial carcinomas and prognostic relevance

AIMS: To investigate episialin/MUC1 expression in the normal, hyperplastic and neoplastic endometrium, and relate patterns of tumour MUC1 reactivity with histopathological characteristics, oestrogen and progesterone receptor (ER and PR) status, bcl-2 and p53 oncoproteins and with clinical behaviour. METHODS AND RESULTS: We studied 42 normally cycling endometria, 45 endometrial hyperplasias of various forms, and 111 endometrial carcinomas of endometrioid and non-endometrioid cell types with specific monoclonal antibodies employing standard immunohistochemical techniques. The follow-up period ranged from 34 to 182 months with a median of 86 months. Epithelial mucin episialin/MUC1 was consistently expressed in the normal endometrium, following a cyclical pattern: "apical membrane staining" in early and mid-proliferative endometrium; "purely cytoplasmic staining" in late proliferative endometrium; and "cytoplasmic staining with intraluminal secretions" in secretory endometrium. Immunostaining patterns in simple and complex hyperplasia were similar to late proliferative endometrium, while atypical hyperplasias and endometrial carcinomas either simulated patterns of proliferative endometrium or lacked MUC1 reactivity. Membranous MUC1 positivity was statistically more frequent in endometrioid carcinomas compared with carcinomas of non-endometrioid type (P = 0.006). Cytoplasmic MUC1 positivity was significantly associated with poor prognosis, while MUC1-negative carcinomas were associated with PR expression and an improved survival (P=0.04). There was no association of MUC1 patterns with bcl-2 and p53 immunoreactivity or with other histopathological variables. CONCLUSIONS: Episialin/MUC1 is an integral component of the normal premenopausal endometrium and is probably hormonally regulated. It is frequently expressed in endometrial hyperplasias and carcinomas. The loss of MUC1 expression from endometrial carcinomas is associated with a favourable prognosis.     

Inhibin/activin subunits beta-A (-betaA) and beta-B (-betaB) are differentially localised in normal, hyperplastic and malignant human endometrial tissue

Inhibins (INHs) are dimeric glycoproteins composed of an alpha (-alpha) subunit and one of two possible beta (beta-) subunits (betaA or betaB). The aims of this study were to determine the frequency and distribution of INH beta (betaA and betaB) subunits in normal, hyperplastic and malignant human endometrium. Endometrial tissue was obtained from normal, hyperplastic (simple, complex and atypical) and endometrioid adenocarcinoma (EC) and INH-alpha, -betaA and -betaB were labelled using immunohistochemistry and immunofluorescence. INH-betaA and -betaB labelling was increased significantly between the proliferative and secretory phase (p<0.05). The lowest labelling was demonstrated in EC, being significantly lower than in secretory phase (p<0.01) and in simple, complex and atypical hyperplastic tissue (p<0.05). For inhibin-betaB, the most intense labelling was noted in atypical hyperplasia compared to EC (p<0.05). A strong colocalisation of inhibin-alpha and -betaA could be demonstrated in malignant endometrial tissue, suggesting the production of inhibin A within the tumour. Additionally, only limited colocalisation of inhibin-betaB with -alpha subunit could be observed, suggesting the synthesis of activin B rather than inhibin B in malignant endometrium. In conclusion, INH-betaA and -betaB were labelled in normal, hyperplastic and malignant endometrium. Hyperplastic tissue labelled more intensely than EC for the presence of INH-betaA and -betaB, suggesting a substantial function in endometrial pathogenesis and an important role in endometrial carcinogenesis.     

Expression of nm23 in normal, hyperplastic and neoplastic endometrial tissues

This study evaluated the expression of nm23 in curettage specimens from 63 cases of normal, hyperplastic and neoplastic endometrial tissues by immunohistochemistry. The histological diagnoses were as follows: normal proliferative (N = 5) or secretory (N = 5), simple hyperplasia (N = 11), complex hyperplasia (N = 9), atypical hyperplasia (N = 8) and adenocarcinoma (N = 25), consisting of endometrioid adenocarcinoma (N = 15), clear cell (N = 7) and serous papillary adenocarcinoma (N = 3). There was no immunostaining for nm23 protein in the 10 cases of normal endometria and in the 28 cases of endometrial hyperplasia. In contrast, 52% of the adenocarcinomas displayed a cytoplasmic staining pattern which was moderate to strong. This difference was statistically significant (p < 0.0001, chi-square test). nm23 expression in curettage specimens had no predictive value for determining the FIGO stage in the hysterectomy specimens (p = 0.2709, chi-square test). No significant difference for nm23 immunoreactivity was found between the histologic subtypes of endometrial adenocarcinoma (endometrioid versus serous papillary and clear cell, p = 0.1413, chi-square test). In this study, there was no immunostaining of normal endometria or of endometrial hyperplasia (including atypical endometrial hyperplasia) to support the hypothesis that expression of the nm23 gene product is related to the development of endometrial adenocarcinoma. In contrast, nm23 expression was upregulated in many cases of endometrial adenocarcinomas irrespective of the histologic subtype.     

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

AIMS: To investigate proliferation in disease free postmenopausal endometrium and that harbouring endometrial adenocarcinoma-is there a dynamic, yet lurking, potential for atrophic endometrium to give rise to endometrial adenocarcinoma? MATERIAL/METHODS: The study comprised 84 disease free endometria from asymptomatic postmenopausal women who had undergone hysterectomy for prolapse, and 50 endometrioid cell type endometrial adenocarcinomas with adjacent uninvolved postmenopausal endometrium. The non-neoplastic tissues were separated histologically into active, inactive, and mixed forms, although only the first two categories were studied immunohistochemically for oestrogen and progesterone receptors (ERs, PRs), epidermal growth factor receptor (EGFR), Ki-67, and angiogenic activity. RESULTS: All postmenopausal endometria were atrophic, but only 42 were inactive; of the remaining samples, 22 were weakly proliferative and 20 were mixed active and inactive. In contrast, the non-neoplastic component of 43 of the 50 endometrial adenocarcinomas examined was of the active form; four specimens were of the pure and 39 of the mixed form. Interestingly, high ER and PR expression was seen in active and inactive endometria, but only the former were EGFR positive and had high proliferative (Ki-67) and angiogenic activity. A similar trend was also shown by the non-neoplastic atrophic endometrium adjacent to endometrial adenocarcinoma. CONCLUSIONS: At least half of the disease free postmenopausal atrophic endometria show a weak proliferative pattern, either diffuse or focal, probably as a response to continuous low level oestrogenic stimulation. These tissues have a latent, although very small, carcinogenic potential, as demonstrated by the immunohistochemical profile and their frequent association with adjacent endometrial adenocarcinoma.     

β-catenin、Glut-1和PTEN蛋白在子宫内膜样腺癌发生过程中的表达及意义

目的 通过分析子宫内膜上皮内瘤变(EIN)诊断、分类与子宫内膜增生WHO(2003)分类的关系,探讨β-catenin、Glut-1和PTEN蛋白在子宫内膜样腺癌发生过程中的表达及其意义.方法 根据EIN诊断及分类标准,对83例子宫内膜增生病例进行再分类.采用免疫组织化学SP法,对10例增殖期子宫内膜、83例子宫内膜增生及24例子宫内膜样腺癌组织中β-catenin、Glut-1及PTEN蛋白的表达进行检测.结果 (1)83例子宫内膜增生病例中共检出24例EIN病例,总检出率为28.9%(24/83).24例EIN病例中,来自复杂型不典型性增生16例(66.7%,16/24),但EIN的检出率与不典型增生的分级无明显关系(P＞0.05).(2)β-catenin蛋白在增殖期子宫内膜中呈正常表达,良性子宫内膜增生的异常表达率为10.2%(6/59),而EIN和子宫内膜样腺癌的异常表达率(50%,12/24;66.7%,16/24)分别明显高于良性子宫内膜增生(P＜0.01),但二者间的异常表达率差异无统计学意义(P＞0.05).(3)Glut-1蛋白在增殖期子宫内膜、良性子宫内膜增生组织中均呈低表达,而在EIN和子宫内膜样腺癌中的高表达率分别为58.3%(14/24)和70.8%(17/24),均显著高于增殖期子宫内膜及良性子宫内膜增生(P＜0.01),但二者高表达率间差异无统计学意义(P＞0.05).(4)PTEN蛋白在EIN病例中的失表达率(37.5%,9/24)与子宫内膜样腺癌(62.5%,15/24)、增殖期子宫内膜(2/10)及良性子宫内膜增生(28.8%,17/59)比较差异均无统计学意义(P＞0.05),但子宫内膜样腺癌的失表达率则明显高于增殖期子宫内膜及良性子宫内膜增生病例,其差异均具有统计学意义(P＜0.05).结论 β-catenin蛋白的异常表达和Glut-1蛋白高表达是子宫内膜样腺癌发生过程中的早期事件,二者在区别良性子宫内膜增生、EIN和子宫内膜样腺癌中可能是有用的免疫标志物.PTEN蛋白失表达是子宫内膜样腺癌发生过程中的极早期事件,但将其作为EIN病变的诊断性标志物并不恰当.     

Sex steroid receptors in lymphoid cells of human endometrium

Sex steroid hormone action on target tissues is mediated through binding of estrogen and progesterone to specific intranuclear proteins, the estrogen and progesterone receptors (ER and PR). Therefore, in the present report the authors investigated for the presence of ER and PR in lymphoid cells of endometrial stroma that may serve as potential targets for estrogen- and progesterone-mediated effects in endometrium. The presence of ER was shown in nine proliferative and ten secretory endometria and the presence of PR in three secretory and one proliferative endometria. ER and PR were localized by monoclonal antibodies, to the nuclei of cells, with the use of, respectively, peroxidase-antiperoxidase (PAP) and avidin-biotin-peroxidase complex (ABC) methods. Lymphoid cells were then delineated by decoration of their plasma membranes with the use of monoclonal antibodies to HLA-DR, leukocyte common antigen (LCA), Leu-4 (CD3), and IL-2 receptor molecules with the use of an ABC staining procedure. A group of cells in the lymphoid aggregates in endometrial stroma showing membranous staining for HLA-DR, LCA, and Leu-4 molecules had nuclear ER. IL-2 receptor-positive cells were rare in endometrium, and no PR-positive cells were found in lymphoid aggregates. Furthermore, HLA-DR and ER were expressed in the glandular and surface epithelium in the proliferative phase and in occasional glands in the basalis in the late secretory phase. The presence of an ER-positive lymphoid cell population in endometrial lymphoid aggregates suggests that these cells may serve as target cells for estrogen.     

TGF-beta 1 and IGF-1 expression in atrophic post-menopausal endometrium

OBJECTIVES: Endometrial cells may synthetize cytokines and growth factors which may modulate some of the molecular mechanisms of endometrial proliferation and differentiation. PATIENTS AND METHODS: We investigated the role of transforming growth factor beta-1 (TGF-beta 1), insulin-like growth factor-1 (IGF-1) and relative receptors in five tissue samples from atrophic post-menopausal endometria. The control group was represented by proliferative and secretory endometria from 10 healthy, normally-menstratued women. TGF-beta 1 and IGF-1 m-RNA expression was evaluated by Northern hybridization analysis, while TGF-beta 1 and IGF-1 receptors distribution was studied by immunohistochemistry. RESULTS: In atrophic endometria Northern hybridization analysis showed a significant decrease of IGF-1 expression, and an increase of TGF-beta 1 expression compared to proliferative and secretory endometria. By immunohistochemistry it was demonstrated that TGF-beta 1 and IGF-1 receptors were both localized in cell cytoplasm, mainly in the stromal compartment. CONCLUSIONS: The results of our study would suggest a possible role of IGF-1 and TGF-beta 1 in maintaining the quiescent differentiative state of atrophic post-menopausal endometrium. The persistence of IGF-1 and TGF-beta 1 receptors in epithelial compartment could play a key role in proliferative response of atrophic endometrium to exogenous hormone replacement therapy (HRT) or endogenous intervening high estrogens levels.     

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.     

Expression of metastasis-associated protein 1 (MTA1) in benign endometrium and endometrial adenocarcinomas

Endometrial carcinoma is one of the most common malignancies of the female genital tract. Metastasis-associated protein 1 (MTA1) is a component of the Mi-2/nucleosome remodeling and deacetylating complex and acts as a potent corepressor of estrogen receptor in breast cancer cells. MTA1 expression has been demonstrated in various cancers but has never been explored in endometrial carcinoma. We investigated the expression profile of MTA1 in different stages of benign endometrium as well as in endometrial endometrioid adenocarcinoma using immunohistochemistry and Western blotting. In the proliferative and secretory phases, MTA1 was expressed in both the glandular and the stromal compartments and was localized in nucleus and cytoplasm of these cells. MTA1 expression in secretory phase was less prominent when compared with the proliferative phase. In postmenopausal sections, MTA1 staining was observed in both glandular and stromal compartments and was localized in both nucleus and cytoplasm. Western blot analysis of 6 tumor specimens showed increased expression of MTA1 in all the tumors analyzed. Immunohistochemical staining performed on tumor microarray containing 70 endometrial endometrioid adenocarcinomas of various grades showed increased expression of MTA1 in 53 (75.7%) tumors. In grade 1 and grade 2 tumors, MTA1 was present in both nucleus and cytoplasm. Interestingly, in grade 3 tumors, MTA1 was localized in the cytoplasm only. Our results suggest a potential role of MTA1 in endometrial carcinomas.