Quantum dot-based immunofluorescent imaging and quantitative detection of TOP2A and prognostic value in triple-negative breast cancer

Hongmei Zheng,1 Xiang Li,1 Chuang Chen,2 Jian Chen,3 Jinzhong Sun,2 Si Sun,4 Liting Jin,1 Juanjuan Li,2 Shengrong Sun,2 Xinhong Wu1 1Department of Breast Surgery, Hubei Cancer Hospital, 2Department of Breast and Thyroid Surgery, Renmin Hospital of Wuhan University, 3Department of Head and Neck Surgery, Hubei Cancer Hospital, 4Department of Clinical Laboratory, Renmin Hospital of Wuhan University, Wuhan, Hubei, People’s Republic of China Background: Topoisomerase 2 alpha (TOP2A) is a key enzyme in DNA replication and a target of various cytotoxic agents including anthracyclines. Previous studies evaluating the predictive and prognostic values of TOP2A in breast cancer are contradictory, likely secondary to the use of both different detection methods and different cutoff thresholds for positive status. Our own studies have previously confirmed the advantages of quantum dot-based nanotechnology for quantitative analysis of biomarkers relative to conventional immunohistochemistry (IHC). This study was designed to 1) assess the expression of TOP2A, 2) investigate the relationship between TOP2A expression and major clinical pathological parameters, and 3) evaluate the prognostic value of TOP2A by quantum dot-based immunofluorescent imaging and quantitative analytical system (QD-IIQAS) in triple-negative breast cancer (TNBC).Patients and methods: TOP2A expression in 145 TNBC specimens was detected using IHC and QD-IIQAS, and a comparative analysis of the two methods was conducted, including an exploration of the relationship between TOP2A expression and major clinical pathological parameters in TNBC. The prognostic value of TOP2A in TNBC was assessed.Results: A similar antigen localization, a high correlation of staining rates (r=0.79), and a high agreement of measurements (κ=0.763) of TOP2A expression in TNBC were found by QD-IIQAS and conventional IHC (cutoff: 45.0 and 0.45, respectively). TOP2A was significantly higher in larger tumors (P=0.002), hig