Programmed Cell Death Protein-1 Predicts the Recurrence of Breast Cancer in Patients Subjected to Radiotherapy After Breast-Preserving Surgery

Radiotherapy is the most important component of the comprehensive treatment of breast cancer, and immunocompromised patients respond with lower response rate. However, the role of programmed cell death protein-1, a critical immune molecule, in recurrence of breast cancer subjected to radiotherapy is unknown. A retrospective analysis was designed to explore the relevance. A number of 42 patients with early-stage breast cancer undergoing breast-conserving surgery and postoperative radiotherapy (18 recurrence and 24 nonrecurrence) were recruited, and clinical data were obtained. Immunohistochemistry was employed to detect programmed cell death protein-1, and Kaplan-Meier curves were used to analyze recurrence-free survival. The expression of programmed cell death protein-1 was higher in the recurrence group than recurrence-free group (P < .05). Meanwhile, the recurrence-free mean survival was significantly longer in programmed cell death protein-1 low-expression group (68 months) than that in programmed cell death protein-1 high-expression group (56 months). In addition, the levels of T lymphocytes were obviously lower in patients with breast cancer than healthy group, and natural killer showed an opposite tendency. CD4(+) decreased significantly after 1 week radiotherapy and recovered rapidly 3 weeks after radiotherapy. Compared to recurrence-free group, the increment of T lymphocytes were inadequate in recurrence group. These experimental results indicated that the expression of programmed cell death protein-1 in tumor-infiltrating lymphocytes is related to immune disorder and recurrence of patients undergoing breast-preserving surgery and radiotherapy.