Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy with a five-year survival rate of approximately 13%. Patients with PDAC also have an elevated incidence of venous thromboembolism (VTE), despite prophylactic anticoagulation. Thus, there is an urgent need for therapeutic strategies that target tumor progression and hypercoagulability. Protein S (PS), a physiological anticoagulant encoded by the PROS1 gene, has recently been shown to inhibit PDAC growth in preclinical models. To further examine the physiological relevance of intratumoral PS in PDAC, we performed a meta-analysis of four independent PDAC patient cohorts obtained from cBioPortal. Patients were stratified based on low versus high intratumoral PROS1 expression based on below- and above-average mean expression, overall survival, and gene expression of select pro-growth genes, implementing a fixed-effects model. High intratumoral PROS1 expression was associated with a 41.8% reduction in the risk of death compared with low PROS1 expression (pooled hazard ratio = 0.581) within 30 months of diagnosis from survival data in three cohorts. Elevated PROS1 expression correlated with marked downregulation of key genes implicated in PDAC invasion and metastasis, including MMP2 and SNAI2, in all four cohorts. Collectively, these findings suggest that PROS1 is a potential prognostic biomarker and molecular regulator in PDAC and thus support further investigation into the dual role of PS in tumor progression.
Prouse et al. (Wed,) studied this question.