In particular, PAM 50 analysis showed that ER-/PR+ tumors, accounting less than 1% of all BC, are mostly basal like (50-60%), a molecular subtype generally observed in TNBC which can be easily detectable through immunohistochemistry-based method (TFF1, CK5, and EGFR positivity) (26). This evidence concerns the gene KRT5 and breast cancer.