LMP-1 antisense oligodeoxynucleotide treatment enhances sensitivity to etoposide. X50-7 cells were exposed to etoposide in the presence or absence of oligodeoxynucleotide (50 μmol/L in the presence of serum) for 24 hours and assayed for viability by trypan blue exclusion. Values represent the mean ± SD of triplicate samples. (□) LMP-1 antisense-treated; (▪) control oligodeoxynucleotide (SS1)-treated; (▨) untreated control. P values for the mean difference between antisense-treated and SS1-treated cells in the presence of etoposide are as follows: 2 μmol/L, P < .002; 20 μmol/L, P < .001; 20 μmol/L, P = .0002.