The gene-expression microarray and RNA-seq data associated with 40 of the breast cancer cell lines were used for the analyses. The panels illustrate the associations of RARα and PPARβ/δ with ATRA sensitivity. The left panels show the basal average levels of the indicated transcript in the cell lines belonging to the T1 and T3 groups (13 cell lines in each of the T1 and T3 groups) defined by ascending ATRA scores. The intermediate and right panels indicate the same results after stratification for the Luminal (microarray and RNA-seq data = 7 cell lines in each of the T1 and T3 groups) and the Basal (microarray and RNA-seq data = 7 cell lines in each of the T1 and T3 groups) phenotype, respectively. fpkm = fragments per kilobase of exon per million fragments mapped. 