inv(12)(p11.2q13) in an endometrial polyp

A benign endometrial polyp from a 50-year-old postmenopausal woman has been cytogenetically investigated. A single clonal karyotypic anomaly, inv(12)(p11.2q13), was found in about 30% of cells analyzed after short-term culture. This finding contributes further to the hypothesis that the chromosomal segment 12q13-q14, which is also involved in chromosomal rearrangements in uterine leiomyomas, pleomorphic adenomas of the salivary glands, lipomas, and myxoid liposarcomas, contains a gene or genes that are related to cellular proliferation rather than to malignant transformation.     

Amplification and expression of the HMGIC gene in a benign endometrial polyp

In a totally benign endometrial polyp, double minute chromosomes were shown to contain an amplified and apparently nonrearranged HMGIC gene, expressed in the tumor cells, suggesting amplification of HMGIC through double minute chromosome formation as another hitherto unreported mechanism associated with the development of some mesenchymal tumors. Genes Chromosomes Cancer 22:95–99, 1998. © 1998 Wiley-Liss, Inc.     

Demystifying endometrial hyperplasia

The endometrial hyperplasias form a spectrum of proliferative lesions, not all of which conform to conventional definition of hyperplasia. For whilst most hyperplastic lesions are composed of cells normally occurring in the late proliferative phase endometrium, there are those few which consist of genuine atypical cells. Lesions of this type, so-called “atypical endometrial hyperplasias”, tend to merge imperceptibly with well differentiated endometrioid adenocarcinomas, giving rise to major challenges: First and foremost, what are the very essential criteria that should be met before diagnosing such a lesion? And what are the very least that should be insisted upon for diagnosing malignancy once an atypical endometrial hyperplasia has been established? What is its true nature and how should ideally be classified? Other less conflicting, but equally interesting, aspects of endometrial hyperplasia which are covered in this account include the conventional hyperplasias, i.e. those lacking cytological atypia, and the overall incidence, risk factors and treatment of the disease. It is worth noting that “pure” stromal cell proliferations are, in itself, not necessarily neoplastic, for many take the form of endometrial stromal hyperplasia.     

Abnormalities of E- and P-cadherin and catenin (beta-, gamma-catenin,and p120ctn) expression in endometrial cancer and endometrial atypical hyperplasia

Abnormal expression of cadherins and catenins plays a critical role in the initiation and progression of multiple human tumours. This study aimed to evaluate the immunoreactivity of E- and P-cadherin, beta- and gamma-catenin, and p120ctn in premalignant and malignant endometrial lesions and to correlate their membranous expression with clinicopathological features. In addition, we examined whether or not LOH and promoter hypermethylation of the CDH1 gene were associated with E-cadherin expression and clinicopathological variables. Finally, we studied the frequency of beta-catenin mutations in premalignant endometrial lesions. Immunohistochemical staining was performed in 21 atypical endometrial hyperplasias (AEHs), 95 endometrioid carcinomas (EECs), and 33 non-endometrioid carcinomas (NEECs). Reduced E-cadherin expression was observed in 57.8% of the cases, being more frequent in NEECs (87.1%, p = 0.001) and carcinomas of more advanced stage (85.7% of stage III-IV carcinomas, p = 0.01). LOH of CDH1 gene was found in 57.1% of NEECs but only in 22.5% of EECs (p = 0.011) and showed a trend towards association with reduced E-cadherin expression (p = 0.089). CDH1 promoter hypermethylation was found in 21.2% of endometrial carcinomas but was not associated with clinicopathological or immunohistochemical variables. Reduced expression of beta- and gamma-catenin and p120ctn was found in 76.1%, 94.3%, and 63.6% of the cases, respectively, being more frequent in lesions with reduced E-cadherin expression. In addition, beta-catenin, but not gamma-catenin or p120ctn expression, was associated with the histology of the lesion, since it was reduced in 35% of AEHs, 80.3% of EECs, and 96.9% of NEECs (p = 0.000). Mutations in exon 3 of the beta-catenin gene, associated with beta-catenin nuclear expression, were detected in 3 (14.0%) AEH, a frequency similar to that previously reported in this series of ECs. Finally, upregulation of P-cadherin was observed in 28.6% of cases. This alteration was associated with the histology of the lesion, since it was found in 9.5% of AEHs, 27.7% of EECs, and 46.2% of NEECs (p = 0.021).     

Nuclear and cytoplasmic bcl-2 expression in endometrial hyperplasia and adenocarcinoma

The bcl-2 proto-oncogene, which inhibits programmed cell death (apoptosis), has recently been found to be cyclically expressed in human endometrium. In order to investigate its role in endometrial hyperlasia and neoplasia, bcl-2 expression was studied in 25 cases of endometrial carcinoma and 20 cases of endometrial hyperplasia (eight simple, two complex, and ten atypical hyperplasias). Uniform intense cytoplasmic bcl-2 expression was found in all cases of non-atypical hyperplasia, and less strong positivity in eight out of ten cases of atypical hyperplasia. In well-differentiated carcinomas, nine out of ten showed weak to moderate bcl-2 expression, whereas six out of seven poorly differentiated carcinomas were bcl-2-negative. Moderately differentiated tumours were an intermediate group, with six out of eight being positive. Widespread localization of bcl-2 protein to the chromosomes of dividing cells was also demonstrated, regardless of cytoplasmic bcl-2 expression, with rare staining of interphase nuclei. Our findings suggest a role for bcl-2 in the natural history of endometrial neoplasia and studies are needed to determine its usefulness as a prognostic marker. The finding of bcl-2 localization to chromosomes has important implications for its mode and site of action.     

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.     

p53 expression, p21 expression and the apoptotic index in endometrioid endometrial adenocarcinoma

AIMS: Although several genetic abnormalities are known to occur in endometrial cancer, including tp53 gene mutation, the pathogenesis of this common malignancy remains poorly defined. We investigated the relationship between overexpression of p53 protein, p21 protein expression and apoptosis in endometrial carcinoma. METHODS AND RESULTS: Sixteen cases of endometrial carcinoma in which polymerase chain reaction analysis had demonstrated the absence of a tp53 gene mutation were selected on the basis of p53 protein expression; p21 protein expression and the apoptotic index were then determined for each case. The proportion of cells in each case expressing p53 and p21 protein immunoreactivity was compared with the apoptotic index. Overall, no significant correlation was demonstrated between p53 and p21 immunoreactivity, or between either p53 or p21 and the apoptotic index. CONCLUSIONS: Factors other than p53 are involved in the regulation of p21 expression and apoptosis in endometrioid endometrial adenocarcinomas without p53 mutations. Despite the small numbers used in this study, the data suggest a correlation between low levels of p53 immunoreactivity and apoptosis. We postulate that high levels of p53 immunoreactivity may be due to abnormal stabilization of the p53 protein. Follow-up studies are needed with a larger data set.     

Clonal 6p21 rearrangement is restricted to the mesenchymal component of an endometrial polyp.

Previous cytogenetic analyses revealed t(6;20)(p21;q13) in two endometrial polyps. We karyotyped a large endometrial polyp in which 19 of 25 metaphase cells contained a t(1;6;4)(q21;p21;q13). Subsequent combined immunohistochemical/cytogenetic analysis showed all aberrant metaphase cells to be of mesenchymal derivation, whereas epithelial cells from the polyp were diploid. These studies indicate that rearrangement of chromosome band 6p21 is a characteristic cytogenetic aberration in the stromal component of endometrial polyps.     

卵巢囊腺癌抑癌基因p16检测及其意义

进一步探讨新型抑癌基因Ｐ１６与人类卵巢癌发生发展的关系。方法：采用Ｓ－Ｐ免疫组化方法对母系ＨＯ－８９１０细胞系，高转移ＨＯ－８９１０ＰＭ，ＮＳＭＯ模型和转移瘤以及６９全卵巢癌腺癌手术标本石蜡组织进行Ｐ１６检测。结果。母素ＨＯ－８９１０细胞与高转移ＨＯ－８９１０ＰＭ细胞，ＮＳＭＯ模型及转移瘤均具有Ｐ１６阳性表达，表达强度均以转移细胞为弱。     

Enhanced detection of atypical hyperplasia in endometrial polyps by PTEN expression.

Endometrial hyperplasia is difficult to recognize within endometrial polyps because of the background of randomly distributed irregular glands. The loss of expression of the PTEN oncogene is characteristic of endometrial cancers and clinically significant hyperplasia. Using immunohistochemical staining for the PTEN protein, we studied 12 endometrial polyps that were noted to contain foci of complex hyperplasia or glandular crowding. Loss of PTEN staining was found in 3 cases, suggesting a precancerous lesion. Moreover, 2 of these cases were originally classified as complex hyperplasia without atypia and 1 as merely glandular crowding. Thus, in selected cases, the loss of PTEN expression in an area of glandular crowding can highlight biologically significant lesions and afford a more definitive diagnosis.     

Oxidative stress in endometrial hyperplasia

OBJECTIVE: Reactive oxygen species seem to be involved in the onset and promotion of carcinogenesis. In 80% of cases of endometrial adenocarcinoma type I, a clear association exists with endometrial hyperplasia, which is considered a key factor in the endometrial oncological spectrum. The presence or absence of atypical cells determines oncological potential. This study explored the behavior of oxidative stress (catalase and malondialdehyde) in endometrial hyperplasia (with or without atypical cells) by comparing it with the oxidative stress existing in both the proliferative and secretory phases. DESIGN: Endometrial specimens from 55 women were used, 32 of which were histologically diagnosed as physiological (17 proliferative and 15 secretory endometria) and 23 as endometrial hyperplasia (18 nonatypical and 5 atypical endometrial hyperplasia). RESULTS: Significant differences were found in the malondialdehyde variable between the proliferative endometrium and the endometrium with atypical hyperplasia (P = 0.0208) and between both types of endometrial hyperplasia (P = 0.0441). The other comparisons were not statistically significant. No changes in catalase activity were observed. CONCLUSION: Our findings seem to suggest that the presence of atypical cells in endometrial hyperplasia induces a reduction in lipid peroxidation, which could permit survival and growth of these cells. This possible decrease in lipid peroxidation does not seem to be mediated by an increase in endometrial catalase activity.