Immunohistochemistry performed on our previously described22, in-house cohort of over 100 BC patients confirmed areas of invasive carcinoma with SqD expressed higher levels of TFAP2A and TFAP2C relative to invasive conventional UCC (Fig. 5d–n and Supplementary Table S2; p < 0.001, p = 0.015, respectively, Wilcoxon rank sum test). Here, TFAP2A is linked to breast cancer.