To detect molecular alterations associated with BrCa, we performed DNA whole‐exome sequencing (WES) (mean coverage = 537x, min = 282x, max = 731x) and RNA deep sequencing (mean depth = 88 M reads, min 56 M reads, max = 97 M reads, detecting 13009 transcripts on average at cpm > 5, min = 8545, max = 19113) respectively on cfDNA and EV‐RNA isolated from two HER2+ (PMB2.8 and PMB2.36) and two HER2‐ (PMB2.26 and PMB2.30) BrCa patients (Table S1 for patient marker status, Table S2 for WES coverage, Table S3 for cfDNA and EV quantification and Table S4 for RNAseq statistics). The gene discussed is ERBB2; the disease is invasive breast carcinoma.