The concentrations of assessed VD active forms, 25(OH)D2, 25(OH)D3, and 25(OH)D, as well as catabolites, 24,25(OH)2D3 and 3-epi-25(OH)D3, decreased in BC patients after 3 and 6 months of CTH compared to the baseline (Table 2). This evidence concerns the gene CTH and breast cancer.