Furthermore, KK-LC-1 protein was found overexpressed specifically in the TNBC cell lines MDA-MB-231 and MDA-MB-468 compared to multiple non-TNBC breast cancer cell lines, including the ER−HER2+ breast cancer cell line SKBR3, the ER+ breast cancer cell line MCF7, the ER+HER2+ breast cancer cell line BT474 and the breast epithelial cell line MCF10A (Supplementary Fig. 1h, i)22. Here, ERBB2 is linked to breast cancer.