Investigation of Programmed Death Ligand-1 as a New Prognostic Biomarker in Pancreatic Cancer Patients.

Pancreatic cancer is one of the most lethal and fast-growing cancers with a poor prognosis. Herein, we report the expression of programmed death ligand 1 (PD-L1) as a new prognostic biomarker in pancreatic cancer progression analysis at the clinical level. Immunohistochemistry was performed on 86 clinically proven cases of pancreatic cancer tissue microarrays (TMAs) using anti-PD-L1 antibodies. Histoscore was done, and a variety of cutoffs were identified for analyses of the results. The chi-square test and Kaplan-Meier method were used to find the association between pancreatic cancer and various clinicopathological variables and the overall survival of the patients. PD-L1 expression was associated with histological grade and recurrence of the disease for epithelial and stromal staining at 10 histoscores. In addition, PD-L1 expression was strongly associated with lymph node involvement at the stromal 20 histoscore. The tumor stage of pancreatic cancer had an association with PD-L1 expression with epithelial and stromal 20 histoscores for all comparisons. At a stromal 20 histoscore, overall survival in high-low expression of PD-L1 was 7-19 months, and at a nuclear/cytoplasmic 10 histoscore, it was 9-28 months (p = 0.0001), respectively. Overall, PD-L1 overexpression in subcellular compartments was associated with disease aggression phenotypes and poor patient survival. Overexpression of PD-L1 was directly linked to pancreatic cancer progression and a poor survival rate. Therefore, PD-L1 may be used as a prognostic biomarker in the diagnosis, treatment, and management of pancreatic cancer patients.