A Comparative Study on PD-1 and PD-L1 Gene Expression and Concentration in Malignant and Benign Breast Tumors among Iraqi Women

Background: Breast cancer represents the most common form of cancer among women and is a leading cause of cancer-related deaths. Timely identification is crucial for improving therapeutic outcomes. Objective: This study examines the functions of Programmed cell death -1 (PD1) and Programmed death-ligand 1 (PD-L1)in the preliminary detection of breast cancer in Iraqi women. The aim of the study is to characterize the functional implications of single-nucleotide variations in programmed cell death 1 (PD-1) and programmed death ligand 1 (PD-L1) in conjunction with other peripheral immune checkpoints to assess the immune competence of breast cancer patients, and to evaluate the gene and protein expression levels of immune checkpoints such as PD-1 and PD-L1 in samples obtained from patients diagnosed with breast cancer. Methodology: A case-control study was conducted involving 70 women diagnosed with malignant breast cancer,25 benign breast tumor and 25 healthy controls. Blood samples were collected, and immunological parameters, including PD1 and PDL1 levels, were measured using the ELISA technique, in addition molecular study to determine expression levels of PD1 and PDL1 were quantified using quantitative real-time PCR (qPCR). Results: The results showed that the ages 50-59 years, had the highest percentage of breast cancer patients. Histologically, invasive ductal carcinoma (IDC) was the most common type. BMI was associated with an increase in breast cancer risk in women. The results showed highly significant differences in PD-1 concentration between healthy subjects (1.627±0.12 aa), and patients with benign (9.246 ± 1.27 aa) and malignant (18.021±0.61 aa) tumors at a significance level of P = 0.0001**, and the LSD test (2.607) confirmed the significance of the differences between the groups. PDL_1 increased in Benign (8.615±0.32), and Malignant (12.768±0.49) breast disease patients compared with apparently healthy controls (4.339 ±0.44). PD1 and PDL1 gene expression levels were elevated in malignant breast cancer, with fold increases of 2.8 and 3.1 times, respectively, compared to benign cases. Conclusion: The results of the current study indicate that elevated levels of PD1 and PDL1 are closely associated with breast cancer malignancy, suggesting their potential role as biomarkers for early detection.