In order to validate the readthrough ability of G418 for this RB1 nonsense mutant, we transiently transfected the RB1-negative breast carcinoma cell line MDA-MB-436 with a construct containing the complete RB1 R579X nonsense mutant cDNA with an N-terminal FLAG tag (Fig 1B, see R579X). The gene discussed is RB1; the disease is breast carcinoma.