Expression pattern of telomerase reverse transcriptase in rectal carcinoma predicts tumor radiosensitivity, local recurrence and disease-free survival.
OBJECTIVE
Predictive indicators of radiosensitivity in rectal cancer are required in order to avoid unnecessary preoperative radiotherapy. Telomeres are specialized structures at the ends of chromosomes that protect against that such as irradiation. Lower telomerase activity has been reported to be related to radiosensitivity in vitro or vivo. The aim of this study was to examine the possible role of telomerase reverse transcriptase expression, which is correlated to telomerase activity, in determining tumor radiosensitivity, local recurrence, and disease-free survival in patients with rectal carcinomas.


METHODS
We studied 96 cases with advanced rectal carcinoma. In preradiation biopsy specimens of tumor samples, the number of cells stained positive for telomerase reverse transcriptase protein was evaluated by immunohistochemistry.


RESULTS
The expression pattern of telomerase reverse transcriptase protein correlated with tumor radiosensitivity (P=0.0007). All tumors that had a high percentage of telomerase reverse transcriptase positive cells were radioresistant. High telomerase reverse transcriptase expression pattern is a predictive marker for high local recurrence or poor survival in patients with rectal cancer (P=0.011, P=0.0005). Telomerase reverse transcriptase expression and histopathological grade were significant prognostic variables for disease-free survival in the multivariate analysis (P=0.0003, P=0.0091).


CONCLUSIONS
Telomerase reverse transcriptase raises the predictive possibility of tumor radiosensitivity in rectal cancer. Telomerase reverse transcriptase might be a useful parameter for patient selection for preoperative radiotherapy in rectal carcinoma.
Komuro
Yasuhiro
Y
Department of Surgical Oncology, Faculty of Medicine, University of Tokyo, Japan. komuro@kt.rim.or.jp
Watanabe
Toshiaki
T
Tsurita
Giichiro
G
Muto
Tetsuichiro
T
Nagawa
Hirokazu
H
D000230:Adenocarcinoma / Q000201:enzymology* / Q000401:mortality / Q000628:therapy; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004268:DNA-Binding Proteins; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009364:Neoplasm Recurrence, Local / Q000201:enzymology*; D011237:Predictive Value of Tests; D011836:Radiation Tolerance / Q000502:physiology*; D012004:Rectal Neoplasms / Q000201:enzymology* / Q000401:mortality / Q000628:therapy; D019098:Telomerase / Q000378:metabolism*; D016896:Treatment Outcome
D004268:DNA-Binding Proteins; D019098:Telomerase