Fig. 1: Claudin-low tumors are distributed across luminal-like IntClust3, basal-like IntClust10, and CNA-devoid IntClust4, which harbors rare focal genomic alterations.

a Repartition of breast tumors from the METABRIC cohort for each molecular subtype among integrative clusters. Number of tumors are represented on the y axis and the corresponding percentages are indicated above each bar. All tumors (n = 1266); claudin-low tumors (n = 45); basal tumors (n = 129); HER2 tumors (n = 102); luminal A tumors (n = 461); luminal B tumors (n = 429). b, c Identification of focal genomic alterations in a CNA-devoid IntClust4 claudin-low sample (MB-6052/FGA < 0.3%). b BAF and LRR plots of SNPs localized in genomic regions of copy number deletion (LRR < 0.4). c Mutation analysis from targeted sequencing data. BAF: B allele frequency; CNA: copy number alteration; FGA: fraction of genome altered; IntClust: integrative cluster; LRR: log R ratio; SNP: single-nucleotide polymorphism.