VDR and breast cancer: We next used hypergeometric optimization of motif enrichment (HOMER) for transcription factor (TF) motif discovery within 1,25(OH)2D‐sensitive open chromatin (Supplemental Worksheet S10).(47) From this analysis, GATA3 was the most highly associated TF identified (Fig. 5G), whereby GATA3 is essential for normal tissue development(48) and is commonly mutated in breast cancers.(49) Not surprisingly, the VDR motif was the second most highly correlated nuclear TF identified from our analysis.