Keratin as a Potential Prognostic Biomarker for Breast Cancer Progression: An Evidence-Synthesizing Narrative Review

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• Breast cancer (BC) is a leading cause of female mortality globally.
• Reliable biomarkers are crucial for BC prognosis and personalized treatment strategies.
• Keratins, diverse intermediate filament proteins, are vital histopathological markers due to their specific expression patterns in epithelial differentiation.

Purpose of the Study:

• This narrative review explores the prognostic potential of keratin subtypes in breast cancer.
• It focuses on keratins extensively used for differentiating specific BC subclasses.
• The review aims to highlight keratins as valuable prognostic markers.

Main Methods:

• A structured literature search was conducted using PubMed and Scopus databases.
• Elements of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework were adapted for search and screening transparency.
• The review included 79 studies: 11 in vitro, 6 in vivo, and 62 human studies.

Main Results:

• Five significant keratin types (K5/6, K19, K8/18, K14, K17) are expressed in specific BC subtypes and influence tumor progression.
• These keratins aid in prognostic stratification, early detection of metastatic potential, and guiding adjuvant therapy decisions.
• They function as predictive biomarkers for chemotherapy effectiveness, risk assessment in triple-negative breast cancer (TNBC), and targeted therapies.

Conclusions:

• Keratins actively contribute to tumor progression and are involved in key oncogenic pathways.
• The findings underscore the importance of keratins as prognostic and predictive biomarkers in breast cancer.
• This highlights potential for developing updated BC therapies targeting keratin pathways.