ERBB2 and ductal breast carcinoma in situ: Nevertheless, neither does this approach allow for a conclusive comparison of treatment modalities or cancer subtypes (i.e., DCIS versus invasive, Her2 positive versus Her2 negative, Luminal A versus Luminal B, TNBC versus HR + or early-stage versus metastatic carcinoma) nor one should expect the cases to produce, for instance, an age distribution that aligns with the epidemiological or demographic data of a specific population, e.g. on national level for a specific country.