High Ki-67 labeling index in human colorectal cancer with microsatellite instability.
BACKGROUND
In the present study, we examined the relationships between microsatellite status and Ki-67 labeling index, a proliferative marker, in colorectal cancers in order to clarify the common biological profiles of familial and sporadic cases of MSI (microsatellite inability)-positive tumors.


METHODS
Seventy-eight invasive colorectal carcinomas were studied. Five microsatellite loci were analyzed by polymerase chain reaction, while Ki-67 was studied by immunohistochemistry.


RESULTS
The MSI was found in 15 (19.2%) of the 78 tumors, and the Ki-67 labeling index was significantly higher in the 15 MSI-positive tumors than that in the 15 MSI-negative ones (p = 0.0181). Moreover, the Ki-67 labeling index was significantly higher in the 7 tumors with MSI at more than 2 loci (MSI-H; high-frequency MSI) than that in the MSI-negative ones (p = 0.0082).


CONCLUSIONS
The present study demonstrates that colorectal cancers with MSI show high Ki-67 labeling index irrespective of hereditary or nonfamilial cancer types, suggesting their common biological aspects distinct from MSI-negative ones.
Takagi
Sho
S
Division of Gastroenterology, Tohoku University Graduate School of Medicine, 1-1 Seiryo, Aoba, Sendai 980-8574, Japan. stakagi@int3.med.tohoku.ac.jp
Kumagai
Shinji
S
Kinouchi
Yoshitaka
Y
Hiwatashi
Nobuo
N
Nagashima
Fumio
F
Takahashi
Seiichi
S
Shimosegawa
Tooru
T
D000368:Aged; D002455:Cell Division / Q000502:physiology; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism*; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics*
D019394:Ki-67 Antigen