Identification of the Thioredoxin-Like 2 Autoantibody as a Specific Biomarker for Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) has a higher risk of death within 5 years of being diagnosed than the other forms of breast cancer. It is the second leading cause of death due to cancer among women. Currently, however, no diagnostic blood-based biomarker exists to identify the early stages of TNBC. To address this point, we utilized a human protein microarray system to identify serum autoantibodies that showed different expression patterns between TNBC and normal serum samples, and identified five autoantibodies showing TNBC-specific expression. Among them, we selected the thioredoxin-like 2 (TXNL2) autoantibody and evaluated its diagnostic relevance by dot blot analysis with the recombinant TXNL2 protein. We demonstrated that the TXNL2 autoantibody showed 2- to 6-fold higher expression in TNBC samples than in normal samples suggesting that serum TXNL2 autoantibodies are potential biomarkers for TNBC.