Cathepsins are well-known pro-invasive enzymes that, by degradation of proteins of the extracellular matrix as well as by processing of various growth factors or cytokines, remodel the tumor microenvironment and contribute to their growth, invasion, and metastasis; Cathepsin-D (CTSD) is the major lysosomal protease in mammals [42]. This evidence concerns the gene CTSD and neoplasm.