The potential of cystatin C as a predictive biomarker in breast cancer

ABSTRACT

Introduction

Breast cancer (BCa) is the leading cause of cancer-related deaths among women. Numerous efforts are being directed toward identifying novel tissue and/or circulating molecular markers that may help clinicians in detecting early-stage BCa patients and in providing an accurate estimation of the prognosis and prediction of response to clinical treatments. In this setting, emerging evidence has indicated Cystatin C (Cyst C), as the most potent endogenous inhibitor of cysteine cathepsins, as a possible useful marker in the clinical management of BCa patients.

Areas covered

This review analyzes the results of emerging studies underpinning a potential clinical role of Cyst C, as additional marker in BCa.

Expert opinion

Cyst C expression levels have been reported to be altered in tumor tissues and/or in biological fluids of BCa patients. Furthermore, clinical evidence has highlighted a significant correlation between altered Cyst C levels in tumor tissues and/or biological fluids and some clinco-biological parameters of BCa progression. These findings provide evidence for a potential clinical use of Cyst C as a novel marker to improve the clinical and therapeutic management of BCa patients and as a gauge for better clarifying the role of cysteine proteinases in the various steps of BCa progression.

KEYWORDS:

• Breast cancer
• cathepsins
• cystatins
• cysteine proteinases
• cystatin C
• metastasis
• proteinase inhibitors
• tumor markers
• tumor progression

Article highlights

• Breast cancer (BCa) is the leading cause of cancer-related deaths among women. However, this disease has a good long-term prognosis when detected in its early stages.

• Current efforts are being directed towards identifying novel-specific markers that may help clinicians in detecting early-stage BCa.

• Growing evidence has uncovered the involvement of lysosomal cysteine proteinases and some of their endogenous inhibitors, in particular Cystatin C (Cyst C), in breast cancer progression.

• Numerous clinical investigations have been undertaken to assess the clinical impact of Cyst C in breast cancer.

• The results from studies suggest that Cyst C might have a role as novel marker in the early detection and therapeutic monitoring of BCa patients and as a useful tool to provide further insight on the role of cysteine proteinases in various steps of breast cancer progression. Finally, these findings suggest Cyst C as potential molecular target for the development of novel therapeutic options in cancer treatment based on proteinase inhibitors.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.