[1522] Utility of E-Cadherin and ProEx C Immunohistochemistry in the Differential Diagnosis of Benign and Malignant Eccrine Lesions

H Ashby-Richardson, PA Phadke, A Shephard-Barry, NM Laver. Tufts Medical Center, Boston, MA

Background: Endocrine mucin-producing sweat gland carcinoma (EMPSGC) is a rare, eccrine neoplasm with a predilection for the eyelid of elderly females. The frequent coexistence of EMPSGC with benign eccrine ducts as well as invasive carcinoma, suggests it is a part of a multistage progression from benign eccrine ducts to invasive carcinoma. This study explores two molecules, E-cadherin and ProEx C, which have been linked in tumor progression. E-cadherin, a transmembrane glycoprotein, has a critical role in calcium-dependent cell-cell adhesion in epithelial tissues and is vital to the formation and maintenance of an epithelial monolayer. Loss or aberrant expression of E-cadherin has been associated with tumor invasion and metastatic potential in a variety of human cancers. Additionally, re-expression of E-cadherin in highly tumorigenic human cancer cell lines confers a less invasive phenotype. ProEx C is an antibody reagent that detects minichromosome maintenance (MCM) and topoisomerase II alpha (TOP2A) proteins, both of which play an important regulatory role in eukaryotic DNA replication and have been shown to be over-expressed in a number of different dysplastic and malignant tissues.
Design: 3 cases of eccrine hidrocystoma, 4 cases of EMPSGC and 3 cases of eccrine carcinoma were studied. Immunohistochemical staining for E-cadherin and ProEx C was performed on formalin-fixed paraffin-embedded tissue. Expression of E-cadherin was deemed positive if diffuse, complete membrane staining and negative if absent or incomplete membrane staining was observed. In addition, the intensity of staining was graded from 0 to 3+. Cases were evaluated for expression of ProEx C based on the percentage of tumor cells showing nuclear staining.
Results: The results are listed in Table 1.

Table 1

	E-Cadherin Expression	ProEx C Expression
Eccrine Hidrocystoma (n=3)	3+	<1%
EMPSGC (n=4)	2-3+	5-20%
Eccrine Carcinoma (n=3)	0	>35%

Conclusions: The decreased E-cadherin and increased ProEx C expression in EMPSGC and eccrine carcinoma as compared to benign eccrine hidrocystomas further support the hypothesis that this tumor is part of a multistage progression from benign eccrine lesions to invasive carcinoma. Immunostaining with these two molecules may aid in distinguishing benign from malignant eccrine lesions.
Category: Ophthalmic

Tuesday, March 10, 2009 9:30 AM

Poster Session III # 214, Tuesday Morning