[The detection of microsatellite instability in carcinoma and adenoma of large bowel and its significance].
OBJECTIVE
To explore the role of microsatellite instability (MSI) in colorectal carcinogenesis and the relationship between MSI, proliferation activity and prognosis.


METHODS
PCR-SSLP and immunohistochemistry methods were used to detect MSI and the expression of PCNA in 56 cases of carcinomas, 9 cases of adenomas and 6 cases of adenomas with malignant changes.


RESULTS
The total positive rate of MSI were 25/56 cases in colorectal carcinomas. The MSI positive cases were 3/4 in HNPCCs, 22/52 in sporadic colorectal carcinomas, 2/9 in adenomas and 2/6 in adenoma with malignant changes respectively. The PCNA labelling index of MSI positive tumors were significantly lower than that of MSI negative tumors (P < 0.01). The 3 and 5 year survival rates in patients with MSI positive colorectal carcinomas were higher than those of MSI negative tumors.


CONCLUSIONS
MSI may be an early molecular alteration and another molecular mechanism in colorectal carcinogenesis. The MSI positive tumors have low proliferating activity and a better clinical outcome. The detection of MSI might be useful in predicting prognosis of colorectal carcinomas.
Yan
X
X
Department of Pathology, Southwest Hospital, The Third Military Medical University, Chongqing 400038.
Chen
Y
Y
Liu
F
F
Luo
Y
Y
He
G
G
Lu
R
R
Fang
D
D
D000236:Adenoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D000328:Adult; D000368:Aged; D002455:Cell Division; D015179:Colorectal Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D004273:DNA, Neoplasm / Q000235:genetics; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics*; D008875:Middle Aged; D011379:Prognosis; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D017384:Sequence Deletion; D016019:Survival Analysis
D004273:DNA, Neoplasm; D018809:Proliferating Cell Nuclear Antigen