Distribution of epithelial membrane antigen in normal and abnormal endometrial tissue

Validation of tissue microarray technology in endometrioid cancer of the endometrium

AIM

To validate tissue microarray (TMA) for endometrial cancer by comparing immunohistochemical staining results of triplicate core biopsies on TMA with the results of full-section analysis.

METHODS

The study material consisted of slides and selected tissue blocks of 41 patients with endometrioid cancer of the endometrium. A TMA was constructed. Both the TMA and the slides were stained with the same antibodies against progesterone receptor (PR), oestrogen receptor, p53 and epithelial membrane antigen (EMA). Concordance between results was expressed as the kappa statistic.

RESULTS

Concordance between the staining results of TMA and whole slides was good for PR (kappa = 0.69), oestrogen receptor (kappa = 0.78), p53 (kappa = 0.81) and EMA (kappa = 0.72). Concordance between the results on TMA and slides depends on the number of assessable cores per tumour. Three assessable cores per case result in outcomes that are at least 94% similar to those achieved using conventional tissue sections with a two-class scoring system. This is independent of focal or diffuse staining patterns.

CONCLUSION

TMA is a useful tool for further analysis of the molecular pathways in endometrial cancer. The effect of selection has to be taken into account when the prognostic value of protein expression on TMA is determined.

A comparison of epithelial membrane antigen overexpression in benign and malignant endometrium

OBJECTIVE

The aim of this study was to analyze the value of epithelial membrane antigen (EMA) overexpression in benign and malignant endometrium and its prognostic significance.

METHODS

EMA immunostaining was performed in 178 paraffin-embedded specimens including 105 endometrial cancers, 40 endometrial hyperplasias, and 33 benign endometriums. EMA immunostaining was correlated with traditional prognostic factors and progression-free survival in endometrial cancer specimens.

RESULTS

EMA overexpression was observed more frequently in adenocarcinomas (60%) than in hyperplasias (15%) or benign endometrium (9.1%). EMA overexpression was observed in two patients with endometrial hyperplasia who progressed to carcinoma. In adenocarcinomas, EMA overexpression had a positive correlation with nonendometrioid subtypes (P = 0.012). In multivariate analysis, FIGO stage (P = 0.025) and EMA overexpression (P = 0.017) were independent prognostic factors for progression-free survival.

CONCLUSIONS

EMA overexpression appears to be a marker of malignant transformation in the endometrium and it is an independent predictor of recurrent disease in endometrial cancer.

Expression of carcinoembryonic antigen and ferritin in normal, hyperplastic, and neoplastic endometrium

The distribution of carcinoembryonic antigen (CEA) and ferritin was demonstrated by immunohistochemical method in 95 patients with normal, hyperplastic, and neoplastic endometrium in order to distinguish among these conditions. Fifteen patients with normal endometrium (NE), 28 with hyperplasia (AH), 12 with atypical hyperplasia (AAH), and 40 with endometrial carcinoma (CA) were studied. Paraffin section tissues were subjected to immunostaining according to the avidin-biotin complex method. CEA was found in 33% of NE cases, 46% of AH, 75% of AAH, and 83% of CA (P less than 0.01). Ferritin was not detected in any case of NE; however, it was detected in one case (4%) of AH, in one case (8%) of AAH, and in 88% of CAs (P less than 0.001). Both tumor markers exhibited a heterogeneous staining pattern, and for a given histologic hyperplastic or malignant lesion, corresponded to several phenotypes. There was no significant correlation between clinical stage or tumor grade and CEA or ferritin expression. In conclusion, ferritin seems to be a better biological marker than CEA in distinguishing between hyperplastic and neoplastic endometrial lesions and it is also more reliable than CEA for endometrial malignancy since it was absent in normal and hyperplastic endometria.

Value of immunohistochemical demonstration of several epithelial markers in hyperplastic and neoplastic endometrium

The distribution of prekeratin, vimentin, epithelial membrane antigen (EMA), and secretory component (SC) was demonstrated immunohistochemically in 31 patients with adenomatous hyperplasia (AH), 12 patients with atypical adenomatous hyperplasia (AAH), and 39 patients with endometrial carcinoma. Prekeratin was presented in 94% of AHs, 92% of AAHs, and 87% of adenocarcinomas. Vimentin was detected in 68% of AHs, 50% of AAHs, and 37% of adenocarcinomas, showing decreased expression as the lesion progressed to malignancy (P less than 0.05). EMA was detected in 26% of AHs, 67% of AAHs, and 95% of adenocarcinomas (P less than 0.001). SC demonstrated focal and weak expression in 29% of AHs, but showed increased staining intensity in 67% of adenocarcinomas (P less than 0.01). Well-differentiated tumors expressed SC better than poorly differentiated tumors (P less than 0.01). All markers showed a heterogeneous staining pattern and, for a given histologic hyperplastic or neoplastic state, corresponded to several phenotypes. In conclusion, prekeratin seems to be a good marker for epithelial differentiation in hyperplastic endometrium, and EMA is a good marker in neoplastic endometrium. In hyperplastic lesions, the loss of vimentin expression in the absence of secretory changes gives rise to suspicions regarding their benign process. Also, EMA can help in distinguishing between hyperplastic and neoplastic states, while detection of SC may be of help in more precise grading of endometrial carcinoma.