Jianhua Fang, Yi Shao, Jiezhi Su, Ying Wan, Lingyun Bao, Wei Wang, Fanlei Kong

This study explored the value of measuring programmed death 1 (PD-1) in peripheral blood, combined with breast ultrasound using the Breast Imaging Reporting and Data System (BI-RADS) classification, for differentiation between benign and malignant breast tumors. We enrolled 113 patients with breast cancer and 66 patients with benign breast tumors who were admitted to Hangzhou First People's Hospital from September 2014 to August 2017. The mRNA level of PD-1 was detected by quantitative real-time polymerase chain reaction. The mRNA levels of PD-1 were significantly higher in the peripheral blood of patients with breast cancer than those in patients with benign breast tumors. The diagnostic sensitivity of PD-1 mRNA expression was 0.805, the specificity was 0.788, and the area under the curve (AUC) was 0.848 (P < 0.001); the sensitivity of breast ultrasound-based BI-RADS classification was 0.752, the specificity was 0.909, and the AUC was 0.906 (P < 0.001); and the combined sensitivity, specificity, and AUC of the two assays were 0.920, 0.879, and 0.938, respectively (P < 0.001). Progesterone receptor-positive breast cancer patients exhibited high levels of PD-1 expression (P < 0.001). This study suggests that the measurement of PD-1 combined with breast ultrasound-based BI-RADS classification represents a significant improvement for breast cancer diagnosis compared with diagnoses based on either method alone.