Expression of c-Myc and Fas correlates with perineural invasion of pancreatic cancer.

Lymph node metastasis (LNM) and perineural invasion (PNI) are regarded as two important prognostic factors in pancreatic cancer. The aim of this study was to identify the LNM-associated and PNI-associated markers in pancreatic cancer. We have constructed a formalin-fixed paraffin embedded pancreatic tissue microarrays containing 324 cylindrical tissue cores of human pancreatic cancer and its paracancerous nonmalignant pancreatic specimens (NMPs) from 162 patients. Among those patients, there were 83 of 162 with PNI, and 65 of 162 with LNM. The protein products of 2 genes encompassing a variety of functional classes, such as oncogenes (c-Myc), apoptosis (Fas), were analyzed by immunohistochemistry on the tissue microarray. There was marked increase in cancer tissues cytoplasmic c-Myc expression level in pancreatic cancer compared with the NMPs (P < 0.0001). Additionally, the expression level of c-Myc was also significant increase in pancreatic cancer with PNI compared with cancer without PNI (P < 0.01). In contrast, cytoplasmic Fas, low expressed in pancreatic cancer (P < 0.0001) was negatively correlated with PNI (P < 0.05). Logistic regression analysis showed that the c-Myc expression in the cancer tissues cytoplasm acted as a potential and independently predictive factor for PNI. However, there were no significant association between the expression of these two genes and LNM (P > 0.05). This study for the first time described expression levels of c-Myc and Fas played an important role in PNI of pancreatic cancer. Combined detection can be used as predictive factors, especially c-Myc.