Expression of Cathepsin-D in Primary Breast Cancer and Corresponding Local Recurrence or Metastasis: An Immunohistochemical Study

Background/Aim: The role of cathepsin-D is well established in breast cancer progression, being correlated with worse clinical outcomes. However, to our knowledge, no study has been performed investigating its expression in primary breast cancer tumors and their corresponding recurrences or metastasis. Materials and Methods: Tissue sections from ten breast cancer cases and their corresponding local recurrences and six breast cancer cases and their corresponding metastases were immunohistochemically assessed for cathepsin-D reactivity. Cases diagnosed as either ductal carcinoma in situ (n=7), or breast carcinoma with no evidence of local recurrence or metastasis during follow-up (n=8) served as controls. Results: Cathepsin-D was significantly up-regulated in all the study groups compared to controls. No difference was found between primary tumors and their corresponding recurrences or metastases. Conclusion: Cathepsin-D-expressing breast cancer cells seem to be involved in local recurrence or metastasis formation. Large series are needed to further verify this result with the aim of possible future molecular intervention. Cathepsin-D is a soluble aspartic protease found in lysosomal and endosomal cellular compartments (1). The cathepsin-D gene has been reported as both a housekeeping gene and as a hormone-regulated gene. Its promoter has several regulatory sites among which are a 5'-TATAAA-3' DNA sequence (TATA-box) and two p53-binding sites (2, 3).