Objective: To study the clinicopathological significance of the expression of calreticulin (CRT) protein and mRNA in pancreatic ductal adenocarcinoma (PDAC).
Methods: The expression of CRT protein in 33 paired paraffin embedded PDAC specimens and adjacent non-cancerous pancreatic tissues were detected by immunohistochemistry. Western blot and RT-PCR were used to examine the expression of CRT protein and mRNA in 12 paired fresh PDAC specimens and adjuvant non-cancerous pancreatic tissues. The relationship between the protein expression and clinicopathological features was analyzed.
Results: CRT expression was much higher in 33 PDAC tissues than that in paired adjacent non-cancerous pancreatic samples (t = 2.323, P = 0.027). CRT was over expressed in 16 PDAC tissues, but only in 8 adjuvant non-cancerous pancreatic tissues (48.5% vs. 24.2%). The expression of CRT protein had no correlation with tumor position (χ(2) = 1.588, P = 0.208), differentiation (χ(2) = 1.517, P = 0.218), TNM stage (χ(2) = 2.528, P = 0.112) and lymph node metastasis (χ(2) = 1.963, P = 0.161), but had statistic significancy with the prognosis of the patients (χ(2) = 4.080, P = 0.043). The median survival time in the patients with high expression of CRT protein was longer than that in the patients with low expression. The expression of CRT mRNA was higher in PDAC than that in non-cancerous tissues detected by RT-PCR (t = 2.539, P = 0.025), but no significant difference was found in protein level (t = 1.292, P = 0.223).
Conclusions: CRT is up-regulated in PDAC and may be a prognosis factor for patients with PDAC.