High telomerase activity is an independent prognostic indicator of poor outcome in colorectal cancer

Telomerase activity and altered telomere length have been extensively studi ed in many kinds of malignant tumors for clinical diagnostic and/or prognos tic utilities. In the present study, we investigated telomerase activity an d telomere length in colorectal cancers and noncancerous colonic mucosa spe cimens in 100 patients between 1991 and 1996, To determine whether the leve l of telomerase activity or telomere length is a prognostic indicator of pa tient outcome, we followed these patients more than 3 years after surgery. Among 100 primary colorectal cancer specimens, 96 specimens had telomerase activity. Because noncancerous mucosa has some detectable telomerase activi ty, we divided the levels of telomerase activity into three categories: hig h (>50fold more than that in noncancerous mucosa); moderate (10-to 50-fold) ; and low (<10-fold) levels. Among 100 cancer tissues, 28 showed moderate t elomerase activity and 44 showed high telomerase activity. The frequency of tumors with moderate or high telomerase activity showed no significant rel ationship with any clinicopathological factors. The prognosis of the patien ts with high telomerase activity was significantly worse than that for pati ents with moderate and low telomerase activity (P < 0.01). Among the 87 pat ients with curative surgery, disease-free survival rate of those with high telomerase activity was also significantly poorer (P < 0.01). These results indicate that a high level of telomerase activity may be an independent pr ognosis-predicting factor in the patients with colorectal cancer.