Responsiveness of CPT-11 in respect to hMLH1 and hMSH2 protein expression in the primary colorectal cancer.
OBJECTIVE
The aim of this study was to evaluate the responsiveness to CPT-11 with respect to hMLH1 and hMSH2 protein expressions in primary colorectal tumors.


METHODS
91 patients with colorectal cancer treated having undergone surgery and postoperative CPT-11-based adjuvant chemotherapy, between 1997 and 2002, were prospectively recruited. Tumor samples were immunohistochemically analyzed for the expressions of hMLH1, hMSH2, p53 and CEA proteins.


RESULTS
Of the 91 tumors, 6 (6.6%) and 4 (4.4%) showed loss of hMLH1 and hMSH2 protein expressions, respectively. The response rate of patients with tumors not expressing either hMLH1 or hMSH2 was higher than that of those expressing either of these proteins (p=0.026). Patients with tumors not expressing hMLH1 showed a significantly better response to CPT-11 (p=0.04). The responsiveness was not associated with the expressions of hMSH2, p53 or CEA. There were no correlations between drug toxicity and the expressions of hMLH1, hMSH2 or p53. The overall survival was better in patients responsive to CPT-11-based chemotherapy compared to non-responders.


CONCLUSIONS
The immunohistochemical determination of loss of hMLH1 and hMSH2 expressions may be used in determining the responsiveness to CPT-11-based chemotherapy. Our results suggest that hMLH1 protein expression may be a predictor for CPT-11 responsiveness in patients with colorectal cancer.
Park
In Ja
IJ
Department of Surgery, University of Ulsan College of Medicine, Seoul, Korea.
Kim
Hee Cheol
HC
Yu
Chang Sik
CS
Chang
Heung Moon
HM
Lee
Jea Hwan
JH
Kim
Jong Hoon
JH
Kim
Tae Won
TW
Kim
Jung Sun
JS
Kim
Jin Cheon
JC