Microsatellite instability testing in Korean patients with colorectal cancer.
Microsatellite instability (MSI) testing is useful for identifying patients with hereditary nonpolyposis colorectal cancer and detecting sporadic colorectal cancer that develops through replication error pathways. A pentaplex panel is recommended by the National Cancer Institute for MSI testing, but simplified mononucleotide panels and immunohistochemistry of mismatch repair proteins are widely employed for convenience. This study was to evaluate the MSI status of colorectal cancer in Korean patients. This study included 1,435 patients with colorectal adenocarcinoma subjected to surgical resection. The pentaplex Bethesda panel was used for MSI testing. Seventy nine (5.5 %) carcinomas were classified as MSI-high (MSI-H) and 95 (6.6 %) as MSI-low (MSI-L). BAT-26 and BAT-25 were unstable in 73 and 75 of 79 MSI-H carcinomas, respectively. With the panel comprising these 2 mononucleotide markers, 72 carcinomas were diagnosed as MSI-H, compared to the Bethesda panel data (72/79, 91.1 %). In contrast, BAT-26 or BAT-25 were unstable in only 7 (7.4 %) of the 95 MSI-L tumors. In the panel with 2 dinucleotide markers, D17250 linked to p53 and D2S123 to hMSH2, detection rates were 89.9 % (71/79) for MSI-H and 80.0 % (76/95) for MSI-L carcinomas, compared to the Bethesda panel. Moreover, we compared the frequency of MSI tumor in our patients with those reported previously from Western countries. In conclusion, the frequency of MSI-H appears lower in colorectal cancer patients in Korea. A simplified panel for MSI testing with BAT-26 and BAT-25 seems not effective for the accurate evaluation of MSI status, particularly in MSI-L colorectal carcinomas, in our patients.
Department of Surgery, Seoul National University Bundang Hospital, 166 Gumi-ro, Bundang-gu, Seongnam, 463-707, Korea.
Jung Ryul
JR
Oh
Duck-Woo
DW
Kim
Hye Seung
HS
Lee
Hee Eun
HE
Lee
Sung Min
SM
Lee
Je-Ho
JH
Jang
Sung-Bum
SB
Kang
Ja-Lok
JL
Ku
Seung-Yong
SY
Jeong
Jae-Gahb
JG
Park
D000230:Adenocarcinoma / Q000235:genetics* / Q000601:surgery; D044466:Asian People / Q000235:genetics; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000601:surgery; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000235:genetics; D006801:Humans; D053842:Microsatellite Instability; D056910:Republic of Korea