Serum Platelet Factor 4 Is an Independent Predictor of Survival and Venous Thromboembolism in Patients with Pancreatic Adenocarcinoma

Abstract

Improved diagnostic, predictive, and prognostic biomarkers for pancreatic ductal adenocarcinoma (PDAC) are urgently needed. Platelet factor 4 (PF4) has been proposed as a diagnostic biomarker for PDAC. We assessed the diagnostic and prognostic potential of serum PF4 levels in PDAC patients. Serum PF4 levels were determined by enzyme-linked immunosorbent assay in an initial cohort of 62 PDAC patients, 62 healthy control subjects, and 34 chronic pancreatitis patients. A second validation set consisted of 71 PDAC patients. Linear regression models were used to relate PF4 to class, gender, age, stage, platelet count, and diagnosis. Survival analyses were done using univariate and multivariate Cox models. In the initial cohort, serum PF4 levels distinguished PDAC from chronic pancreatitis patients (P = 0.011), but not from healthy control subjects (P = 0.624). In PDAC patients, high serum PF4 level significantly predicted decreased survival independent of all covariates examined (P < 0.01). The prognostic relationship of serum PF4 levels remained significant in the validation set. Venous thromboembolism (VTE) occurred in 20% of the 133 PDAC patients. The VTE risk was higher in subjects with elevated PF4 levels (P = 0.009). Serum PF4 is shown for the first time to be prognostic for survival in PDAC patients. High PF4 is associated with an increased risk for the development of VTE. Serum PF4 levels may be useful for patient stratification and for directing treatment options in patients with pancreatic cancer including anticoagulation prophylaxis. The relationship between high PF4 levels and poorer outcomes requires further study.