Effect of dsRNA-EGFR on chemosensitivity of NSCLC cells to cisplatin. Cells were transfected with siRNA, then exposed to various doses of cisplatin for 48 h and viability was accessed. The percentage of cell growth was calculated by comparison of the A490 reading from treated versus control cells. The IC50 value of A549 (upper) cells to cisplatin in control group, transfection reagent control, unrelated dsRNA group and dsRNA-EGFR group was 2.67 μg/ml, 2.30 μg/ml, 2.19 μg/ml and 0.50 μg/ml respectively. The IC50 value of SPC-A1 cells to cisplatin (lower) was 3.67 μg/ml, 3.11 μg/ml, 3.07 μg/ml and 0.43 μg/ml respectively.