CTSL and breast cancer: In addition, lα, 25-(OH)2D3 has a novel role in DNA repair in various tissues or in some disease processes, such as in breast cancer, and lα, 25-(OH)2D3 enhances the stabilization of the 53BP1 levels and the blockage of cathepsin L (a positive biomarker for triple-negative breast cancer) to treat or mitigate the tumorigenesis [59].