ESR1 and ductal breast carcinoma in situ: Viale et al. compared TargetPrint microarray readouts to central IHC and results showed a concordance rate of 98% for ER, 92% for PR, and 75% for HER2, followed by secondary analysis for the discordant cases, and the overall conclusion was that the presence of DCIS or intratumoral heterogeneity does not support the reason for the discordance rates they previously reported [24, 25].