KRAS and breast cancer: In support of the histological data, no significant difference in expression of BC (KRT5 and TP63), secretory (MUC5AC, MUC5B and SCGB1A1), ciliated (FOXJ1 and DNAI1) and squamous (KRT6B and IVL) cell markers was observed between cells infected with control lentivirus and lentivirus expressing WT KRAS at any time point (Fig. 4e).