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Updated: Jul 14, 2026
Deficient Pms2, ERCC1, Ku86, CcOI in Field Defects During Progression to Colon Cancer
Published on: July 28, 2010
Microsatellite instability in poorly differentiated adenocarcinomas of the colon and rectum: relationship to
Yoshihiro Kazama1, Toshiaki Watanabe, Takamitsu Kanazawa
1Department of Surgical Oncology, University of Tokyo, Tokyo, Japan.
Background:
Poorly differentiated adenocarcinomas of the colon and rectum (Por) feature the worst prognosis among the various types of colorectal carcinomas. Por is highly associated with microsatellite instability (MSI), although MSI is associated with an improved prognosis in colorectal cancers.
Aim:
To investigate the influence of MSI on clinicopathological features and survival of patients affected by Por.
Methods:
53 patients affected by Por were investigated. DNA extracted from tumour sections and the corresponding normal tissue was analysed by PCR at five microsatellite loci: BAT25, BAT26, D2S123, D5S346 and D17S250. Tumours with alterations at two or more loci were classified as MSI-Por. The others were classified as microsatellite stability (MSS)-Por. The clinicopathological features and survival of patients with MSI-Por and MSS-Por were investigated.
Results:
Of the 53 patients who were examined, 12 (22.6%) were MSI-Por, whereas 41 (77.4%) were MSS-Por. Significant differences were found between MSI-Por and MSS-Por regarding the following clinicopathological features: age, gender, lymph-node metastasis (MSI-Por: 4/12; MSS-Por: 33/41), TNM stage (MSI-Por: T1/T2/T3/T4 = 2/6/2/2; MSS-Por: 3/3/19/16) and lymphatic invasion (MSI-Por: 4/10; MSS-Por: 27/35). Kaplan-Meier survival curves and log-rank analysis showed that MSI-Por was associated with better prognosis than MSS-Por, although no significant difference was found.
Conclusions:
Compared with MSS-Por, MSI-Por is significantly associated with a low incidence of lymph-node metastases and a low stage. This indicates that MSI-Por is a less aggressive subtype.
