Overexpression of Programmed Death-Ligand 1 Receptor mRNA as an Independent Negative Prognostic Factor for Triple Negative Breast Cancer.

BACKGROUND: Triple negative breast cancer (TNBC) (represents roughly 25% of all breast cancers in Yogyakarta) still has the worst survival compared to other breast cancer subtypes. Results from recent studies have shown that inhibition of programmed death-ligand 1 receptor (PD-L1) in TNBC patients is associated with better prognosis. Currently, data on PD-L1 expression and its prognostic value in Indonesian TNBC patients are still relatively unknown. This study aimed to investigate the expression of PD-L1 in Indonesian TNBC patients as preliminary proof to support PD-L1 inhibitor as a possible treatment option near in the future. METHODS: We retrospectively included stage I-III TNBC patients diagnosed between 2014 and 2017 in Dr. Sardjito Hospital, Yogyakarta, Indonesia. Clinical variables were collected from medical record. Paraffin blocks of biopsy specimen were retrieved to examine mRNA level of PD-L1. RESULTS: We included 48 subjects with mean age of 51.09 years and mean body mass index (BMI) of 24.58. The 3-year overall survival (OS) was 58.3%. Overexpression of PD-L1 mRNA in TNBC patients is associated with worse prognosis (P < 0.01). There were no statistically significant associations between PD-L1 mRNA expression and any of the clinicopathologic variables examined. CONCLUSIONS: In summary, PD-L1 mRNA overexpression is associated with worse survival in Indonesian TNBC patients, independent of other established risk factors. PD-L1 mRNA is expressed in all of our samples, presenting as a feasible alternative or complementary method in deciding which patient might benefit from receiving PD-L1 inhibitor.