Lidocaine downregulates the expression of EGFR in RB cells. Expression of EGFR (A) mRNA and (B) protein in RB and normal adjacent tissues (a1, a2 and a3, RB tissues; b1, b2 and b3, normal adjacent tissues) n=30/group. Data are presented as the mean ± standard deviation. **P<0.01 vs. normal tissues. Expression of EGFR (C) mRNA and (D) protein in RB cell lines and the retinal pigment epithelial cell line ARPE-19 and RB cell lines. Data are presented as the mean ± standard deviation of three independent experiments performed in triplicate. *P<0.05, **P<0.01 vs. ARPE-19. Expression of EGFR (E) mRNA and (F) protein in Y79 cells following treatment with 500 µM lidocaine for 24 h. Data are presented as the mean ± standard deviation of three independent experiments performed in triplicate. **P<0.01 vs. control. RB, retinoblastoma; EGFR, epidermal growth factor receptor.