The dilemma: Does tissue expression of cathepsin D reflect tumor malignancy? The question: Does the assay truly mirror cathepsin D mis-function in the tumor?

Three molecular forms of the proteolytic enzyme Cathepsin D (CD) are found in the cell: the precursor (proCD), the intermediate single-chain and the mature double-chain. ProCD, which is found in the Golgi Complex, is enzymatically inactive, while the