Immunohistochemical evaluation of tissue-specific proteolytic enzymes in adenomas containing foci of early carcinoma: correlations with cathepsin D expression and other malignant features.

Abstract

Background: Cathepsin D (CD) is an aspartyl lysosomal protease, and the prognostic value of CD expression has been studied in a variety of tumors, however, its role in early adenocarcinomas remains unclear.

Aim of the study: We evaluated the expression of CD in a series of colorectal adenomas with severe dysplasia containing foci of early carcinoma and compared the results to several histopathological and immunohistochemical features.

Methods: Adenomas were obtained by endoscopic polypectomy from 33 patients. Twenty-four of the 33 adenomas contained well-differentiated adenocarcinomas and nine adenomas contained moderately differentiated adenocarcinomas.

Results: Positive CD expressions were observed in 25% of well-differentiated adenocarcinomas and in 66.7% of moderately differentiated adenocarcinomas (p < 0.05). Of the 12 adenocarcinomas with positive CD expression, four had positive CD expression in their adenomas (p < 0.01), 6 showed positive Ki-67 expression in their adenomas (NS), and 10 had positive p53 expression in their adenomas (p < 0.05). No significant association was seen between the level of CD expression and adenoma size.

Conclusions: The expression of CD in adenocarcinoma correlated significantly with differentiation, and with the levels of CD and p53 expression in the adenomas of the polyp.