Morphogenesis of nonpolypoid colorectal adenomas and early carcinomas assessed by cell proliferation and apoptosis.
Nonpolypoid neoplasms, as well as ordinary polypoid tumours, are occasionally found in the colorectum. To clarify whether cell kinetic status affects the macroscopic morphology of colorectal neoplasms, we investigated proliferative indices (PI), apoptotic indices (AI), and the expression of apoptosis-related gene products. We examined 110 colorectal neoplasms comprised of 36 polypoid, 38 flat elevated and 36 depressed tumours. According to WHO's criteria these tumours consisted of 61 adenomas with low grade dysplasia (LGD), 30 adenomas with high grade dysplasia (HGD) and 19 carcinomas with submucosal invasion. Apoptotic cells were detected by TUNEL staining. Proliferating cells and apoptosis-related gene products were assessed by immunohistochemistry for Ki-67, p53, Bcl-2, and Bax antigens. AI were closely associated with macroscopic morphology in adenomas but not in carcinomas. PI were relatively constant among the three macroscopic types in adenomas and carcinomas. Median AI values of polypoid, flat elevated and depressed tumours were 1.8%, 2.1% and 4.6% for adenomas with LGD, 0.8%, 2.4% and 6.2% for adenomas with HGD and 2.9%, 4.0% and 3.6% for carcinomas, respectively. Overall PI were significantly higher in carcinomas than in adenomas with LGD, whereas AI were not different. Although the incidence of expression was significantly higher in carcinomas for p53 and in adenomas for Bcl-2 than the others, the expression of apoptosis-related gene products (p53, Bcl-2 and Bax) was similar among polypoid, flat elevated and depressed tumours. Macroscopic morphology of colorectal adenomas is determined by the apoptosis not by proliferation, and high apoptosis found in depressed adenomas implies their low net growth.
Nomura
M
M
Third Department of Internal Medicine, Asahikawa Medical College, Midorigaoka-Higashi, Japan.
Watari
J
J
Yokota
K
K
Saitoh
Y
Y
Obara
T
T
Kohgo
Y
Y
D000236:Adenoma / Q000473:pathology*; D017209:Apoptosis / Q000235:genetics; D002455:Cell Division; D015179:Colorectal Neoplasms / Q000473:pathology*; D053938:DNA Fragmentation; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D007413:Intestinal Mucosa / Q000473:pathology; D019394:Ki-67 Antigen / Q000032:analysis; D009361:Neoplasm Invasiveness; D011518:Proto-Oncogene Proteins / Q000032:analysis; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis; D016159:Tumor Suppressor Protein p53 / Q000032:analysis; D051028:bcl-2-Associated X Protein
C494826:BAX protein, human; D019394:Ki-67 Antigen; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein