Early carcinogenic events in HNPCC adenomas: differences with sporadic adenomas.
BACKGROUND
Tumorigenesis in hereditary nonpolyposis colorectal cancer (HNPCC) differs from that in sporadic colorectal cancer during the early stage. We examined the expression of proliferation- and apoptosis-regulating proteins in relation to proliferation and apoptosis in HNPCC and sporadic adenomas.


METHODS
Proliferation and apoptosis were quantified, and the expression of cyclin B1, D3 and E, p21, p27, bcl-2, bax, p53 and cox-2 was determined by immunohistochemistry in 100 patients (42 with HNPCC and 48 with sporadic adenomas).


RESULTS
No differences between the two groups of patients in terms of proliferation and apoptosis were detected. Low-grade dysplastic HNPCC adenomas differed from sporadic ones by expressing bcl-2 more often (69 vs. 42%) and bax less often (50 vs. 73%). In comparison to sporadic adenomas, fewer high-grade dysplastic HNPCC expressed cyclin B1 and E (50 and 38% vs. 87 and 87%, respectively), p21 (6% vs. 53%) and bax (31% vs. 80%). In addition, HNPCC adenomas had a lower overexpression of p53 (5 vs. 19%).


CONCLUSIONS
The expression of cell cycle- and apoptosis-related proteins differs between HNPCC and sporadic adenomas from early through to advanced stages although proliferation and apoptosis are not different. These differences may contribute to the different clinical behavior of HNPCC and sporadic adenomas.
Rijcken
Fleur Elise Marie
FE
Department of Gastroenterology and Hepatology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
Koornstra
Jan Jacob
JJ
van der Sluis
Tineke
T
Boersma-van
Ek Wytske
EW
Kleibeuker
Jan H
JH
Hollema
Harry
H
D000236:Adenoma / Q000473:pathology*; D017209:Apoptosis; D016009:Chi-Square Distribution; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D018709:Statistics, Nonparametric
D047908:Intracellular Signaling Peptides and Proteins