Relationship between TYMS and ERCC1 mRNA expression and in vitro chemosensitivity in colorectal cancer.

AIM

The aim of this study was to determine whether the relative mRNA expressions of the thymidylate synthase (TYMS) and the excision repair cross-complementing 1 (ERCC1) genes are associated with in vitro chemosensitivity to 5-fluorouracil (5-FU) and oxaliplatin in colorectal cancer, respectively.

PATIENTS AND METHODS

This study included 67 patients with pathologic TNM stage II, III, and IV. TYMS and ERCC1 mRNA expression was determined using real-time reverse transcriptase-polymerase chain reaction (RT-PCR). The chemosensitivity was examined using an ATP-based chemotherapy response assay. A high response was defined as a response producing ≥40% reduction in ATP.

RESULTS

The mean level of TYMS mRNA expression in the groups with low and high response to 5-FU was 2.35×10(-3) ± 2.16×10(-3) 2(-(ΔCt)) and 4.54×10(-3) ± 2.46×10(-3) 2(-(ΔCt)), respectively. The mean level of ERCC1 mRNA expression in the groups with low and high response to oxaliplatin was 13.92×10(-3) ± 9.90×10(-3) 2(-(ΔCt)) and 23.59×10(-3) ± 5.88×10(-3) 2(-(ΔCt)), respectively. Groups with high response to 5-FU and oxaliplatin had significantly higher expression of TYMS and ERCC1 mRNA, respectively (p<0.01 and p=0.01, respectively).

CONCLUSION

High expression of TYMS and ERCC1 mRNA was associated with better in vitro chemosensitivity to 5-FU and oxaliplatin, respectively, in patients with colorectal cancer.