Although indolent and aggressive lesions both classified as Luminal B based on HER2, Ki67, and estrogen receptor (ER) expression27 (Supplementary Fig. 1c–e), aggressive lesions often exhibited spindloid and squamous metaplastic tumor cells, with the latter frequently adjacent to keratin-like structures or keratin pearls (Supplementary Fig. 1a). Here, ERBB2 is linked to neoplasm.