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


OBJECTIVE
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).


METHODS
Retrospective analysis of surgical specimens.


METHODS
Multicenter study.


METHODS
Individuals treated surgically for tumors of the appendix or colorectum.


METHODS
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.


METHODS
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.
Carr
Norman J
NJ
Department of Cellular Pathology, Southampton University Hospitals National Health Service Trust, Southampton, Hampshire, England. Norman.Carr@suht.swest.nhs.uk
Emory
Theresa S
TS
Sobin
Leslie H
LH
D000230:Adenocarcinoma / Q000378:metabolism* / Q000556:secondary* / Q000601:surgery; D000236:Adenoma / Q000378:metabolism* / Q000473:pathology* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis; D001063:Appendiceal Neoplasms / Q000378:metabolism* / Q000473:pathology* / Q000601:surgery; D014408:Biomarkers, Tumor / Q000096:biosynthesis*; D002455:Cell Division; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D018960:Hyaluronan Receptors / Q000096:biosynthesis; D020287:In Situ Nick-End Labeling; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis; D012189:Retrospective Studies; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis
D014408:Biomarkers, Tumor; D018960:Hyaluronan Receptors; D019394:Ki-67 Antigen; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53