Serrated adenoma of the colorectum undergoes a proliferation versus differentiation process: new conceptual interpretation of morphogenesis.
OBJECTIVE
Serrated adenoma (SA) consists of glands both with intraluminal projection of tall columnar cells, which resemble the terminally differentiated cells in the surface epithelium, and with concave short cells, which resemble progenitor crypt cells of the colon. The aim of this study was to clarify the relationship between the serrated architecture and proliferation/differentiation process in SAs.


METHODS
The expressions of both terminally differentiated markers, such as p21, cytokeratin 20 and carbonic anhydrase I, and progenitor/proliferative markers, such as beta-catenin, CD44 and Ki-67, were immunohistochemically examined in 43 SAs and 20 tubular adenomas.


RESULTS
P21-positive cells were more abundant in SAs than in tubular adenomas. Cytokeratin 20 and carbonic anhydrase I expressions were confined to the tall cells, while nuclear beta-catenin and CD44 were expressed in the short cells in SAs. The Ki-67 labeling indices were significantly lower in tall cells than in short ones.


CONCLUSIONS
SAs might undergo both proliferation and terminal differentiation, which is associated with unique serrated configuration.
Jiao
Yu-Fei
YF
Division of Pathology, Central Clinical Laboratory, School of Medicine, Iwate Medical University, Morioka, Japan.
Nakamura
Shin-ichi
S
Sugai
Tamotsu
T
Yamada
Noriyuki
N
Habano
Wataru
W
D000236:Adenoma / Q000145:classification / Q000378:metabolism / Q000473:pathology*; D018256:Adenomatous Polyps / Q000378:metabolism / Q000473:pathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D024401:Carbonic Anhydrase I / Q000378:metabolism; D002454:Cell Differentiation; D003111:Colonic Polyps / Q000378:metabolism / Q000473:pathology*; D015179:Colorectal Neoplasms / Q000378:metabolism / Q000473:pathology*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D005260:Female; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism; D007124:Immunoenzyme Techniques; D053554:Keratin-20 / Q000378:metabolism; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009024:Morphogenesis; D051176:beta Catenin / Q000378:metabolism
C497483:CD44 protein, human; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018960:Hyaluronan Receptors; D053554:Keratin-20; D019394:Ki-67 Antigen; D051176:beta Catenin; D024401:Carbonic Anhydrase I