Cellular DNA, ras p21 and p53 expression in the carcinogenesis of adenomatous colorectal polyps.
OBJECTIVE
To explore the possible roles of cellular DNA, oncogene ras and tumor suppressor gene p53 in the carcinogenesis of colorectal adenomatous polyps (CAP).


METHODS
Cellular DNA content, oncogene ras and tumor suppressor gene p53 expression at the protein level were quantitatively studied with flow cytometry (FCM) in 16 cases of CAP with mild epithelial dysplasia (CAP-MD), 16 cases of CAP with moderate/severe epithelial dysplasia (CAP-M/SD) and 11 cases of cancer in adenomatous polyps (CIAP).


RESULTS
Nuclear DNA contents of CAP-M/SD (DNA [DI] = 1.11 +/- 0.06) and CIAP (DI = 1.29 +/- 0.03) were significantly higher than those of CAP-MD (DI = 1.06 +/- 0.06) and normal controls (DI = 1.00, P < .005) and were in the FCM DNA aneuploidy range. The rates and amount (as determined by the fluoresence index) of mutant p53 protein expression in CAP-M/SD and CIAP were significantly higher than those in the control and CAP-MD groups. Positive rates of ras p21 expression were all high in CAP-MD, CAP-M/SD and CIAP (80%, 75% and 100%, respectively), yet the intensity of expression in the last was significantly stronger than those in the former two groups. DNA aneuploid, ras p21 and p53 coexpression were found in 10 of 11 cases of CIAP.


CONCLUSIONS
The results suggest that cellular DNA, ras p21 and p53 are all involved in the carcinogenesis of CAP. Clinically, the appearance of DNA aneuploidy, ras p21 or p53 overexpression should be considered markers of malignant conversion in CAP.
Zhang
X
X
Department of Pathology, Second Affiliated Hospital, Hebei Medical University, Shijiazhuang, Hebei, People's Republic of China.
Wu
W
W
Lu
H
H
Lu
G
G
Zuo
L
L
D018256:Adenomatous Polyps / Q000378:metabolism* / Q000473:pathology; D000782:Aneuploidy; D002467:Cell Nucleus / Q000235:genetics / Q000473:pathology; D002469:Cell Separation; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000473:pathology; D004273:DNA, Neoplasm / Q000032:analysis*; D004171:Diploidy; D005434:Flow Cytometry; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D008875:Middle Aged; D015689:Oncogene Protein p21(ras) / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
D004273:DNA, Neoplasm; D016159:Tumor Suppressor Protein p53; D015689:Oncogene Protein p21(ras)