Figure 1.

Basal-like/TNBC is associated with an upregulated expression level of the cyclin E/CDK2 partner. (A) Gene expression analysis of primary tumors from Guy’s (TNBC-enriched, n = 177), TCGA (n = 578) and METABRIC (n = 1197) cohorts of CDK and cyclin genes involved in cell cycle. Color scale indicates log2 expression values (yellow, higher; black, lower expression). Cohorts were divided into TNBC, ER+ and HER2+ groups based on their IHC-defined receptor status, in addition to PAM50 classification (Basal-like, HER2-enriched, luminal A, luminal B and normal-like). (B) CCNE1 and CDK2 expression levels were stratified according to their IHC-defined receptor status, or (C) PAM50 classification (Basal-like (BL), HER2, luminal A (LumA), luminal B (LumB) and normal-like (NL)). Median-centered gene expression log2 values are shown. Numbers of patients per group are indicated below the graphs. p-values were determined using a Mann–Whitney U test. (D) Kaplan–Meier curves shows the association of CCNE1 and CDK2 expression (upper quartile (red line) compared to the other curves (black line)) with ten-year overall survival in 1402 breast cancer samples. Significant p-values are indicated with an asterisk, whereas * p < 0.05; ** p < 0.005; *** p < 0.0005.