Prognostic significance of Ku70 protein expression in patients with advanced colorectal cancer.
OBJECTIVE
Ku protein stimulates DNA repair and signals the damage/stress responses, which may affect apoptosis and cell proliferation. The expression of Ku70 has been reported to be related to cell proliferation in a human gastric cancer cell line. However, in colorectal carcinoma, the clinical significance of Ku70 expression remains unclear. We examined the expression pattern of Ku70 in sporadic colorectal cancer and its relation to clinicopathological parameters and survival.


METHODS
We studied 101 consecutive cases of advanced colorectal carcinoma. In resected specimens, the number of cells stained positive for Ku70 protein was evaluated by immunohistochemistry.


RESULTS
The percentage of cells expressing Ku70 in different tumors ranged from 4.2-99.7%. The elevated Ku70 expression group comprised 52 of 101 cases (52%). No significant correlation was seen between Ku expression pattern and the clinical parameters except depth of invasion. pTNM stage, histopathological grade and Ku70 were significant variables for prognosis of survival in the multivariate analysis.


CONCLUSIONS
This is the first report correlating reduced survival with elevated expression of Ku protein in colorectal adenocarcinoma. Ku may be a new prognostic marker useful for selecting adjuvant treatment strategies.
Komuro
Yasuhiro
Y
Department of Surgical Oncology, Faculty of Medicine, University of Tokyo, Japan. komuro@kt.rim.or.jp
Watanabe
Toshiaki
T
Hosoi
Yoshio
Y
Matsumoto
Yoshihisa
Y
Nakagawa
Keiichi
K
Suzuki
Norio
N
Nagawa
Hirokazu
H
D000230:Adenocarcinoma / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D034961:Antigens, Nuclear / Q000378:metabolism*; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D004268:DNA-Binding Proteins / Q000378:metabolism*; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D000072200:Ku Autoantigen; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011379:Prognosis
D034961:Antigens, Nuclear; D004268:DNA-Binding Proteins; C000606509:Xrcc6 protein, human; D000072200:Ku Autoantigen