The Prevalence of PD‑L1 Expression in Triple‑Negative Breast Cancer Patients and Its Correlation with Survival Rates and Other Prognostic Factors: A Survival Analysis

Background: Triple‑negative breast cancer (TNBC) is a leading cause of cancer‑related mortality among women, with a poor prognosis. The programmed cell death 1 (PD‑1) pathway has emerged as a potential immunotherapy target. This study aimed to assess PD‑L1 expression in TNBC patients and its relationship with prognostic variables.

Methods: This cross‑sectional study included 107 TNBC patients recruited between 2016 and 2020. Patient age, tumor grade, and Ki67 expression were obtained from pathology reports. Immunohistochemistry was utilized to determine PD‑L1 status, and 2‑year survival data were collected through telephone follow‑up.

Results: PD‑L1 expression frequency in TNBC patients was 76.6%. Grade 3 was the most common cancer grade, significantly more prevalent in the PD‑L1 positive group (P = 0.01). High Ki67 expression (≥14%) was observed in 89% of patients, significantly higher in the PD‑L1 positive group (P = 0.003). The 2‑year survival rates for the PD‑L1 positive and negative groups were 84.1% and 92%, respectively, with no significant difference between the groups (P = 0.512).

Conclusions: This study investigated PD‑L1 expression prevalence in TNBC patients and its correlation with prognostic variables. PD‑L1 expression was associated with higher tumor grade and elevated Ki67 expression, indicating a potential role in tumor aggressiveness. However, despite these associations, PD‑L1 expression did not significantly impact the 2‑year survival rate in TNBC patients. These results emphasize the complexity of the immune microenvironment in TNBC and the necessity for further research to elucidate the precise role of PD‑L1 in disease progression and patient outcomes.