Expression of component desmosomal proteins in uterine endometrial carcinoma and their relation to cellular differentiation

Abstract

While the assessment of the malignancy of neoplasms is based on morphologic studies of cells and tissues, use of objective molecular markers is leading to a better understanding and more biologically meaningful classification of neoplasms. In recent years, changes in the expression of cell adhesion molecules, especially E-cadherin, catenin, and adenomatous polyposis coli (APC), in carcinomas have attracted the attention of researchers. However, little is known about desmosomes in the uterine endometrium or in endometrial carcinomas. In this study, we semiquantified the desmosomal components desmoplakin I and II and desmoglein, in tissue sections using confocal laser scanning microscopy (LSM), and examined their relationship to the pathological type, the occurrence of lymph node metastases, and the extent of myometrial invasion. Frozen sections of 31 specimens of normal endometrium, 5 specimens of atypical hyperplasia, and 41 specimens of endometrial carcinoma were stained by the immunofluorescence method using antidesmoplakin I and II and antidesmoglein, and these markers were then semiquantified in tissue sections by LSM. The expression and location of desmoplakin I and II and desmoglein were similar, and their expression decreased with loss of differentiation. The expression was lower in cases of lymph node metastasis than in negative cases and was lower in the cases with > one-half myometrial invasion than in cases with < one-half myometrial invasion. Reduction of desmoplakin I and II and desmoglein expression may play an important role in the invasiveness and metastatic activity of human endometrial carcinoma. They can therefore be used as differentiation markers for endometrial carcinoma.