Positive Expression of L1-CAM is Associated with Perineural Invasion and Poor Outcome in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) frequently invades and migrates along neural tissue, which results in local tumor recurrences, distant metastases, and poor prognosis. We evaluated whether L1 cell adhesion molecule (L1-CAM) and glial cell line-derived neurotrophic factor (GDNF) expression in PDAC correlated with neural invasion and overall survival on a large cohort of previously untreated patients. L1-CAM and GDNF were examined by immunohistochemistry in pancreatic cancer tissue samples of 94 cases with PDAC on a tissue microarray. The molecular findings were correlated with pain, clinicopathologic characteristics, and overall survival in these patients. L1-CAM and GDNF were overexpressed in pancreatic cancer tissues compared with the adjacent normal tissues of pancreas. Positive L1-CAM expression was associated with node involvement (P = 0.007), vascular invasion (P = 0.012), perineural invasion (P = 0.001), and higher degree of pain (P = 0.005). In univariate analysis, tissue expression of L1-CAM was associated with poor survival (hazard ratio, 2.508; 95% confidence interval, 1.551-4.053; P < 0.001), and this was also significant in multivariate analysis (hazard ratio, 2.046; 95% confidence interval, 1.200-3.488; P = 0.009). Positive staining of GDNF, neural invasion, and vascular invasion were all statistically significantly related to unfavorable prognosis. Enhanced expression of L1-CAM may contribute to the pain syndrome and perineural invasion and may correlate with poor overall survival in human pancreatic cancer.