MMP13 and breast cancer: Remarkably, several studies from Pérez-Fernández's group have demonstrated that 1,25(OH)2D3 represses the expression of the gene encoding the pituitary transcription factor 1 (PIT1) in breast cancer cells and that PIT1 silencing downregulates SNAIL1, MMP1, and MMP13 proteins [70, 85, 86].