Gene sets associated with ATRA sensitivityUsing the microarray and RNA-seq data associated with the breast cancer cell lines, two ATRA score-associated gene lists ranked for their variable importance were generated. Upper Panels: The gene-expression results of the first 100-ranking genes in the RNA-seq (left) and microarray (right) datasets were used to perform a cluster analysis of the breast cancer cell lines according to the gene-expression profiles. Data are expressed using a log2 scale of the expression signal intensity after normalization of the data across the different cell lines. The genes marked in red are present in both the microarray and the RNA-seq gene sets. The cell lines marked in red are those belonging to the ATRA score T1 group and are sensitive to ATRA, while the ones marked in blue belong to the T3 group and are refractory to the retinoid. The left dark blue lines indicate the genes with higher levels of constitutive expression in the ATRA-sensitive cell lines, while the light blue lines indicate the genes with higher levels of basal expression in the ATRA-refractory cell lines. Lower Panels: The box plots show the enrichment score (single sample Gene Set Enrichment Analysis, ssGSEA) of the microarray (left) and RNA-seq (right) gene sets in the TN (patients 9, 22, 23, 31, 50) and Lum (patients 13, 18, 27, 36, 41, 44, 55, 60, 61, 62, 64) tumors cultured in the absence of ATRA for 48 h. The P-values of the enrichment are indicated. 