KRT5 and breast cancer: According to the expression signatures of PR, HER2, ER, CK5/6, and KI-67, this BC cohort (N = 74) was divided into four subtypes, including Lumina A (n = 14), Lumina B (n = 16), HER2-positive (n = 15), and TNBC (n = 29) patients (Fig. 2A).