Correlation of Tissue Distribution of HLA-G and HLA-E and Degree of Tumor Malignancy in Patients with Breast Cancer

Background and Aims: Human leukocyte antigen (HLA) molecules play a substantial role in T Lymphocyte-mediated adaptive immune response. Down-regulation of HLA expression may help the tumor to escape from immune surveillance. This study aimed to evaluate the correlation between HLA-G and HLA-E tissue distribution and the degree of tumor malignancy in human breast tumors. Materials and Methods: This cross-sectional study was conducted on tissue samples of 145 patients with breast cancer. The distribution of HLA-G and HLA-E expressions were measured by the immunohistochemistry method. Results: Among 145 patients, 51% of tumors did not express HLA-E, and +1 positive was seen in 36.6 % of patients. +2 positive in 8.3% and +3 positive in 4.1% of patients. Moreover, 79.3% of tumors did not express HLA-G, 17.9% expressed +1 positive, 2.8% expressed +2 positive, and no patients expressed +3 positive. Generally, 20.7% and 49% of patients showed expression of HLA-G and HLA-E, respectively. A significant correlation was seen between the grade of disease and expression of HLA-E (p = 0.03) and HLA-G (p = 0.001). Moreover, a significant correlation was seen between the simultaneous expression of HLA-G and HLA-E with grade (p = 0.03, r = 0.176). Conclusion: Significant correlation was seen between the distribution of HLA-G and HLA-E expression with a degree of malignancy. Therefore, these biomarkers’ expression may contribute to the prognosis and progression of breast cancer.