[alpha]-Smooth muscle actin expression and desmoplastic stromal reaction in pancreatic cancer: results from the CONKO-001 study

Previous investigations in pancreatic cancer suggest a prognostic role for α-smooth muscle actin (α-SMA) expression and stromal density in the peritumoural stroma. The aim of this study was to further validate the impact of α-SMA expression and stromal density in resectable pancreatic cancer patients treated with adjuvant gemcitabine compared with untreated patients. CONKO-001 was a prospective randomised phase III study investigating the role of adjuvant gemcitabine as compared with observation. Tissue samples of 162 patients were available for immunohistochemistry on tissue microarrays to evaluate the impact of α-SMA expression and stromal density impact on patient outcome. High α-SMA expression in tumour stroma was associated with worse patient outcome (DFS: P=0.05, OS: P=0.047). A dense stroma reaction was associated with improved disease-free survival (DFS) and overall survival (OS) in the overall study population (DFS: P=0.001, OS: P=0.001). This positive prognostic impact was restricted to patients with no adjuvant treatment (DFS: P