PD-1 Gene Expression as a Possible Diagnostic Biomarker for Breast Cancer

Abstract

     Programmed cell death protein-1(PD-1) is a cell surface protein that can regulate immune response by promoting self-tolerance by suppressing T-cell inflammatory activity. This study aimed to investigate the etiological role of PD-1 gene expression as a biomarker for breast cancer detection and its relationship with clinical characteristics. Eighty peripheral blood samples (fifty blood samples were collected from breast cancer patients and thirty from healthy women as a control group) were randomly recruited to screen the PD-1 gene expression using Quantitative Real Time Polymerase Chain reaction (RT-qPCR). The results showed that the PD-1 gene had a fold change of 8.946 (indicating high expression) and was detected in 80% of patients with tumor grade II. The fold change in PD-1 gene expression ranged from 8 to 10 (high expression) across all tumor stages. 80% of patients were positive for estrogen receptor, with a fold change of 8.571 (high expression), compared to the PD-1 gene control group, which showed a significant association (P≤0.05) with estrogen receptor status. PD-1 gene expression showed a significantly elevated fold change (9.14, p ≤ 0.01) in 64% and 68% of positive breast cancer patients for progesterone receptor and human epidermal growth factor receptor 2 (Her-2), respectively, when compared with the control, a highly significant association depending on the progesterone and human epidermal growth factor receptor 2 status. PD-1 gene expression can serve as an important biomarker and therapeutic target in breast cancer.