In the TCGA data expression of miR-21-5p and miR-21-3p were also significantly higher in tumours belonging to the HER2-like subtype vs other subtypes (Supplementary Fig. S7a,b, P = 5.11 × 10−3 and P = 5.02 × 10−4, respectively, Student’s t-test), while the miR-21-5p adenylation ratio was significantly lower in HER2-like tumours (Supplementary Fig. S7c, P = 0.0013, Student’s t-test). The gene discussed is ERBB2; the disease is neoplasm.