Journal of Pathology and Translational Medicine

Original Articles

Analysis of Microsatellite Instability in Ovarian Epithelial Cancer.: Mee Young Sol, Kyung Un Choi, Jee Yeon Kim, Hyun Jeong Kang, Dong Hoon Shin, Ik Doo Kim, Hyo Seon Choi, Soon Jung Seo; Korean J Pathol. 2007;41(6):380-386.

Abstract PDF: BACKGROUND
The aim of this study was to clarify the incidence and role of microsatellite instability (MSI) in sporadic ovarian epithelial cancers (OEC). We investigated the MSI status and mismatch repair (MMR) protein expression in OEC.
METHODS
MSI was examined by fluorescence- based polymerase chain reaction using five NCI panel markers (BAT25, BAT26, D2S123, D5S346 and D17S250) in 46 cases of OEC. Immunohistochemistry (IHC) for hMLH1 and hMSH2 was performed.
RESULTS
Seven cases (15.2%) exhibited high-frequency MSI (MSIH), one exhibited low-frequency MSI (MSI-L), and the remaining 38 demonstrated microsatellite stability (MSS). MSI-H in OEC was not associated with histologic grade, FIGO stage, tumor size, mitoses or histologic type. Loss of expression of either hMLH1 or hMSH2 was observed in 4 of the 7 (59.3%) MSI-H cases, whereas 4 of the 39 (10.3%) MSI-L or MSS tumors revealed loss of expression of MMR proteins. The sensitivity and specificity of immunohistochemistry for hMLH1 and hMSH2 were 57.1% and 89.7%.
CONCLUSIONS
Our data suggest that a genetic defect in the MMR system might play a role in the carcinogenesis of a minor subset of sporadic OEC however, immunohistochemical testing for hMLH1 and hMSH2 cannot accurately determine microsatellite instability status in OEC.

Genetic Expression Pattern of Gastric Carcinomas According to Cellular Mucin Phenotypes.: Won Ae Lee, In Soo Suh, Ying Hua Li, Ji Hyun Eum, Wan Sik Yu, Han Ik Bae; Korean J Pathol. 2007;41(5):307-315.

Abstract PDF: BACKGROUND
Gastric carcinomas (GCs) have recently been reclassified according to the mucin phenotypes. We aimed to characterize the relationship between the mucin phenotypes and the genetic alterations or the clinicopathologic parameters of GCs.
METHODS
Immunohistochemistry was performed for MUC1, MUC5AC, MUC6, MUC2, CD10, p53, hMLH1, CerbB2 and E-cadherin in 150 GCs. The mucin phenotypes of the GCs were classified as 4 phenotypes: gastric, intestinal, mixed and unclassified.
RESULTS
MUC1, MUC5AC, MUC6, MUC2 and CD10 were expressed in 63.3%, 42.7%, 14.0%, 24.7% and 14.0% of the GCs, respectively. The mucin phenotypes of the GCs corresponded to the gastric type in 31.3%, the intestinal type in 20.0%, the mixed type in 15.3% and the unclassified type in 33.3%. The incidence of a p53 overexpression was higher in the gastric or mixed phenotype than in the intestinal or unclassified phenotype. MUC5AC expression, p53 overexpression and the gastric or mixed phenotype were associated with poor patient survival by multivariate analysis.
CONCLUSION
This study suggests the gastric or mixed mucin phenotype may more likely go through the p53 pathway in carcinogenesis and the mucin phenotype may be considered as a prognostic indicator.

Microsatellite Instability and Mismatch Repair Protein (hMLH1, hMSH2) Expression in Intrahepatic Cholangiocarcinoma.: Yun Kyung Kang, Woo Ho Kim; Korean J Pathol. 2005;39(1):9-14.

Abstract PDF: BACKGROUND
To clarify the role of the mismatch repair (MMR) system in the carcinogenesis of intrahepatic cholangiocarcinoma (ICC), we investigated the microsatellite instability (MSI) status and MMR protein expression in ICC.
METHODS
Thirty-six cases of ICCs were examined by microsatellite analysis for 55 markers that encompassed all of the chromosomal arms and BAT26. An immunohistochemical study for hMLH1 and hMSH2 was also performed.
RESULTS
Widespread MSI (MSI-H) accompanied with a loss of hMLH1 expression was found in one case (2.8%). This MSI-H case was an adenosquamous carcinoma showing intraductal tubulopapillary adenocarcinoma and invasive adenosquamous carcinoma component. Loss of hMLH1 was noted in both components while the frequency and shifted band patterns of MSI were not identical between the components. Another 10 ICCs (27.8%) revealed low level MSI with preserved MMR gene expression.
CONCLUSIONS
Our data suggested that a genetic defect in the MMR system and MSI is not a major pathway in the carcinogenesis of ICC.

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