Expression and Clinical Significance of CacyBP/SIP in Pancreatic Cancer

Aims: Calcyclin-binding protein or Siah-1-interacting protein (CacyBP/SIP), a component of the ubiquitin-mediated proteolysis, could bind SKP1-CUL1-F box protein complex and participate in beta-catenin degradation, which was found to be related to the malignant phenotypes of gastric cancer and renal cancer. However, the role of CacyBP/SIP in pancreatic cancer progression still remains unclear. Therefore, the aim of the present study was to investigate the expression and clinical significance of CacyBP/SIP in pancreatic cancer. Methods: Immunohistochemistry was carried out on paraffin-embedded sections of pancreatic cancer and normal pancreatic tissues. In addition, Western blot and semiquantitative RT-PCR were carried out to analyze mRNA and protein expression of CacyBP/SIP in 8 pairs of freshly resected pancreatic cancer and their adjacent nontumorous tissue. Results: CacyBP/SIP expression was significantly increased in pancreatic cancer tissue (28/68 or 41.2%) and correlated with differentiation degree, higher TNM (tumor, node, metastasis) stage and distance metastasis. Also, mRNA and protein expression of CacyBP/SIP were found to be at higher levels in almost all cancer tissues compared to adjacent tissues. Conclusions: CacyBP/SIP protein might play an important role in the process of pancreatic carcinogenesis and high-level CacyBP/SIP expression might be related to the malignant potential of pancreatic cancer.