Figure 1.

Correlation between IC₅₀ values for 5-FU and mRNA expression levels in the esophageal carcinoma cell lines. The IC₅₀ values for 5-FU were obtained from growth inhibition studies (Table III). The mRNA expression levels (2^−ΔCt) in the cells were evaluated by real-time RT-PCR assay using SYBR^®-Green. The threshold cycle (Ct) values were used to quantify the PCR product, and the relative expression level of the target gene was expressed as 2^−ΔCt. The ΔCt was calculated by subtracting Ct (β-actin; as an internal standard) from Ct (target gene). 5-FU, 5-fluorouracil; RT, reverse transcription.