Referring to copy number alterations, Moelans et al. [67], who included 22 cases of primary and skin metastases from a total of 55 primary BC samples and their corresponding distant metastases, showed a high frequency of CNVs in BC metastases compared with primary tumors for a few genes (ADAM9, IKBKB, PRDM14, CCND1, MED1, ERBB2, CDC6, C11ORF30, CDH1, TRAF4, CPD, CDC6, MAPT, and CCNE1). Here, ERBB2 is linked to breast cancer.