Epithelial neoplasms of the appendix and colorectum: an analysis of cell proliferation, apoptosis, and expression of p53, CD44, bcl-2

CONTEXT

Carcinomas of the appendix are usually well-differentiated mucinous adenocarcinomas that tend to produce pseudomyxoma peritonei and do not show metastatic spread until late in the disease process. In contrast, adenocarcinomas of the colon and rectum rarely result in pseudomyxoma peritonei and frequently metastasize, even if mucinous and well differentiated. These differences in behavior may be reflected by differences at the molecular level.

OBJECTIVES

To examine adenocarcinomas and their precursor lesions (adenomas) of the appendix and colorectum and to determine whether differences exist in the numbers of proliferating and apoptotic cells or in expression of p53, bcl-2, and the standard form of CD44 (CD44s).

DESIGN

Retrospective analysis of surgical specimens.

SETTING

Multicenter study.

PATIENTS

Individuals treated surgically for tumors of the appendix or colorectum.

INTERVENTIONS

Sections were cut from formalin-fixed surgical specimens and immunohistochemical tests were performed for Ki-67 (as a marker of proliferating cells), M30 (as a marker of apoptotic cells), p53, CD44s, and bcl-2.

MAIN OUTCOME MEASURES

Expression of Ki-67, M30, p53, CD44s, and bcl-2 in tumor cells.

RESULTS

The appendiceal adenomas showed significantly lower Ki-67 counts, p53 expression, and bcl-2 expression. When compared with adenocarcinomas of the colorectum in general (mucinous and nonmucinous), the appendiceal adenocarcinomas showed significantly lower Ki-67 counts, M30 counts, and CD44s expression. However, when the analysis was confined to well-differentiated mucinous adenocarcinomas, only the M30 count was significantly different.

CONCLUSIONS

The lower proliferative and apoptotic activity of appendiceal carcinomas and the lower CD44s expression are in keeping with their more indolent behavior compared with adenocarcinomas of the colorectum. However, when only the subset of well-differentiated mucinous adenocarcinomas was compared, only the apoptotic activity was different, suggesting that the other differences were related to the morphologic structure of the lesions.

Biologic characteristics of esophageal epithelial dysplasia assessed by proliferating cell nuclear antigen

BACKGROUND

Proliferating cell nuclear antigen (PCNA) correlates with the cell proliferative state. Using a PCNA specific monoclonal antibody, various malignant neoplasms have been assessed for cell proliferation and malignant potential. However, there are few studies regarding the expression of PCNA in esophageal dysplasia.

METHODS

PCNA expression was immunohistochemically determined in resected specimens from 27 patients with superficial esophageal carcinoma that contained areas with various degrees of dysplasia, carcinoma in situ (CIS), and carcinoma invading the mucosal layer. The authors estimated the cell proliferative activity and biologic characteristics of the basal and parabasal cells of these esophageal epithelial disorders.

RESULTS

The degrees of PCNA labeling index (PCNA LI) of the basal layers were lower than those of the parabasal layers in normal epithelium and dysplastic lesions, respectively, whereas no difference in CIS was recognized between the two layers. The proportion of PCNA LI in the basal layer of moderate dysplasia was lower than that in the basal layer of severe dysplasia. Conversely, there were no statistical differences between severe dysplasia and CIS in both basal and parabasal layers. In terms of lymphocytic infiltration beneath the dysplasia, there was a close relationship between the degree of lymphocytic infiltration and the PCNA index of the basal and parabasal layers.

CONCLUSIONS

PCNA expression may be a useful marker to reflect the biologic characteristics of esophageal dysplasia, suggesting that a high grade of dysplasia is as serious a lesion as esophageal carcinoma.