RB1 and lung cancer: CIS-treated human A549 lung cancer cells produced a significant increase in the expression of p53 (Figure 5A; Supplementary Figure 2A), p21 (Figure 5A; Supplementary Figure 2B), and p16 (Figure 5B; Supplementary Figure 2C), while expression of p-Rb was decreased (Figure 5B; Supplementary Figure 2D).