ERBB2 and breast carcinoma: However, further analysis revealed differences in the USP7 gene on the DNA level between the breast cancer subtypes: particularly luminal A and B tumors showed an amplification of the USP7 gene, whereas HER2 positive and TNBC tumors showed no gene amplification of USP7 but a gain of function of the USP7 gene, which was lower than in the luminal A and B subtypes (Figure S1C).