Real-time PCR assessment of COX-2 mRNA levels. (A) A representative example of COX-2 real-time PCR. Red lines are derived from a patient scoring COX-2 positive by WB, whereas green lines are from a patient scoring COX-2 negative. Although the housekeeping gene GUSB has identical amplification plots, there is a clear difference in the COX-2 mRNA expression level. (B) Results of 10 patients with MM. The calibrator sample for ΔΔCt analysis is a 0.5% HT-29 cell dilution. Negative controls are normal BM samples whereas the positive control is a 10% HT-29 cell dilution. Concordance with WB results is full, since patients 11 to 13 scored COX-2 negative by WB, whereas patients 14 to 20 scored COX-2 positive.