SOX4 and breast cancer: Indeed, analysis of overlap between SOX4-bound sites in HMLE cells and sites identified in two distinct breast cancer cell lines, the HER2-amplified HCC1954 cells and highly metastatic triple-negative MDA-MB-231 cells, revealed a minor degree of overlap in SOX4-bound loci, although the overlap on the associated genes was higher (Figure 1—figure supplement 1H–I).