Objective To study the relationship between the expression of cytochrome c ( Cyt c) and programmed cell death 4 (PDCD4) in pancreatic cancer, and investigate the pathway of PDCD4 inducing the apoptosis of pancreatic cancer cells. Methods Pancreatic cancer specimens from 69 patients who received pancreatic resection from 1990 to 2002 in First Affiliated Hospital of China Medical University were collected. The expression of Cyt c in the 69 paraffin specimens of pancreatic cancer was detected by immunohistochemistry, and the expression of Cyt c in 8 samples of cold-preserved fresh pancreatic cancer and normal pancreatic tissues were detected by Western blot. The expression of PDCD4 and Cyt c in pancreatic cancer was analyzed by paired t test and chi-square test. Results Compared with normal pancreatic tissues, the expression of Cyt c in pancreatic cancer was significantly decreased. The positive expression rate of Cyt c in 69 samples of pancreatic cancer was 41% (28/69). The expression of Cyt c was positive in most patients with positive expression of PDCD4, and the expression of PDCD4 was negative in most patients with negative expression of Cyt c. The expression of PDCD4 and Cyt c was closely correlated with each other (χ2= 10.52, P < 0.05). Conclusions There is a close relationship between the expression of PDCD4 and Cyt c in pancreatic cancer. PDCD4 may induce the apoptosis of pancreatic cancer cells through mitochondrial pathway.

OBJECTIVETo investigate the expression of programmed cell death 4 (PDCD4) protein and its clinicopathological significance in human pancreatic cancer.

METHODSImmunohistochemistry was used to examine the expression of PDCD4 protein in 69 specimens of pancreatic cancer and Western blot in 8 fresh specimens.

RESULTSThe expression of PDCD4 protein was significantly lower in all 8 fresh pancreatic cancer tissues than that in non-cancerous tissues detected by Western blot. Compared with non-cancerous pancreatic tissue (> 80% of positive cells), low PDCD4 expression was shown in 69 pancreatic cancer tissues (< 30% of positive cells in 36 cases and 30%-80% of positive expression cells in 33 cases). In the 33 cases with 30% and 80% of positive expression cells, the expression rates of PDCD4 protein were 57.6%, 24.2%, and 18.2% in well, moderately, and poorly differentiated cancers, respectively. In the 36 cases less than 30% of positive expression cells, however, the expression rate of PDCD4 protein in well, moderately, and poorly differentiated cases were 19.4%, 41.7%, and 38.9%, respectively. 67.4% (15/23) of the moderately differentiated cases and 70% (14/20) of the poorly differentiated cases showed < 30% of positive expression cells. Only 26.9% (7/26) of the well differentiated cases, however, showed < 30% of positive expression cells, indicating that low PDCD4 expression was associated with histological grade (P < 0.01). There was no relationship between PDCD4 expression and other clinicopathological parameters including patients' sex, age, and TNM stage.

CONCLUSIONSExpression of PDCD4 protein is low in human pancreatic cancer and is correlated with the differentiation levels of human pancreatic cancer. PDCD4 may play an important role in the occurrence and development of pancreatic carcinomas.

Adult ; Aged ; Apoptosis Regulatory Proteins ; biosynthesis ; Biomarkers, Tumor ; analysis ; Blotting, Western ; Female ; Humans ; Immunohistochemistry ; Male ; Middle Aged ; Pancreatic Neoplasms ; metabolism ; pathology ; RNA-Binding Proteins ; biosynthesis