KRT5 and ductal breast carcinoma in situ: Based on our data we propose that similar to “DCIS”, triple negative breast cancer is not a single disease that is identifiable by triple negativity for ER/PgR/Her2/neu [6-11], and positivity for EGFR and CK5 expression, but rather are dynamic entities that may be generated in varying proportions or as transitional intermediates in the heterogeneous milieu of the breast tumor.