PURPOSE: To examine the clinical significance of determining the expression levels of DNA topoisomerase- I (topo-I) mRNA of colorectal cancer. METHODS: The relative expression levels of topo-I mRNA in primary colorectal cancer and adjacent normal mucosa were semiquantificated by the RT-PCR method. The relative expression of thymidylate synthase (TS) mRNA of the primary lesions was also examined. RESULTS: The topo- I mRNA expression was higher in the tumorous tissue than in the normal mucosa (n=22, p<0.01). The topo- I mRNA expression did not significantly correlate with 9 clinicopathological variables examined (n=22). In patients who received irinotecan hydrochloride (CPT-11) following the failure of 5-fluorouracil-based treatment, the topoI mRNA expression did not differ nor correlate with the response to CPT-11 (PR, n=14; SD, n=11; PR; n=24) (p=0.91). In these patients, there was no relationship between the topo I mRNA expression and the TS mRNA expression (p=0.22, r=0.18). In addition, the efficacy of CPT-11 did not correlate with combinations subdivided according to the expression levels of topo- I mRNA and TS mRNA. CONCLUSIONS: Determination of topo- I mRNA levels of primary colorectal cancer may not be useful for predicting the efficacy of CPT-11 treatment alone or in combination with TS mRNA levels.
PURPOSE: To examine the clinical significance of determining the expression levels of DNA topoisomerase- I (topo-I) mRNA of colorectal cancer. METHODS: The relative expression levels of topo-I mRNA in primary colorectal cancer and adjacent normal mucosa were semiquantificated by the RT-PCR method. The relative expression of thymidylate synthase (TS) mRNA of the primary lesions was also examined. RESULTS: The topo- I mRNA expression was higher in the tumorous tissue than in the normal mucosa (n=22, p<0.01). The topo- I mRNA expression did not significantly correlate with 9 clinicopathological variables examined (n=22). In patients who received irinotecan hydrochloride (CPT-11) following the failure of 5-fluorouracil-based treatment, the topoI mRNA expression did not differ nor correlate with the response to CPT-11 (PR, n=14; SD, n=11; PR; n=24) (p=0.91). In these patients, there was no relationship between the topo I mRNA expression and the TS mRNA expression (p=0.22, r=0.18). In addition, the efficacy of CPT-11 did not correlate with combinations subdivided according to the expression levels of topo- I mRNA and TS mRNA. CONCLUSIONS: Determination of topo- I mRNA levels of primary colorectal cancer may not be useful for predicting the efficacy of CPT-11 treatment alone or in combination with TS mRNA levels.