Toll-like receptor 2 and Toll-like receptor 4 predict favorable prognosis in local pancreatic cancer

Toll-like receptors play an essential role in our innate immune system and are a focus of interest in contemporary cancer research. Thus far, Toll-like receptors have shown promising prognostic value in carcinomas of the oral cavity, colon, and ovaries, but the prognostic role of Toll-like receptors in pancreatic ductal adenocarcinoma has not been established. We set out to investigate whether Toll-like receptor expression could serve in prognostic evaluation in pancreatic ductal adenocarcinoma, as well. Our study comprised 154 consecutive stage I–III pancreatic ductal adenocarcinoma patients surgically treated at Helsinki University Hospital between 2002 and 2011. Patients who received neoadjuvant therapy were excluded. Tissue microarrays and immunohistochemistry allowed assessment of the expression of Toll-like receptor 2 and Toll-like receptor 4 in pancreatic ductal adenocarcinoma tissue, and we matched staining results against clinicopathological parameters using Fisher’s test. For survival analysis, we used the Kaplan–Meier method and the log-rank test, and the Cox regression proportional hazard model for univariate and multivariate analyses. The hazard ratios were calculated for disease-specific overall survival. Strong Toll-like receptor 2 expression was observable in 51 (34%) patients and strong Toll-like receptor 4 in 50 (33%) patients. Overall, neither marker showed any direct coeffect on survival. However, strong Toll-like receptor 2 expression predicted better survival when tumor size was less than 30 mm (hazard ratio = 0.30; 95% confidence interval = 0.13–0.69; p = 0.005), and strong Toll-like receptor 4 expression predicted better survival in patients with lymph-node-negative disease (hazard ratio = 0.21; 95% confidence interval = 0.07–0.65; p = 0.006). In conclusion, we found strong Toll-like receptor 2 and Toll-like receptor 4 expressions to be independent factors of better prognosis in pancreatic ductal adenocarcinoma patients with stage I–II disease.