We investigated immunohistochemical localization of P-glycoprotein (P-gp) on paraffin-embedded sections from 103 cases of previously untreated pancreatic tumors and also analyzed multidrug resistance-1 (MDR1) gene expression by polymerase chain reaction after reverse transcription in 35 cases. High positive staining for P-gp was observed in 72.8% of pancreatic tumors and in 73.2% of ductal adenocarcinoma. In ductal adenocarcinoma, immunoreactivity of P-gp was inversely correlated with biological aggressiveness of tumors determined by histologic grading (P < 0.01), tumor size (P < 0.01), retroperitoneal invasion (P < 0.01) and portal invasion (P < 0.05). Expression of the MDR1 gene was detected in all the pancreatic tumors examined and was significantly higher than that in normal pancreas (P < 0.05). The levels of MDR1 mRNA showed a moderate correlation with those of P-gp (r = 0.62, P < 0.0001). Higher expression levels of MDR1/P-gp significantly correlated with better prognosis of patients with ductal carcinoma (P < 0.05). Among patients with ductal carcinoma, the high staining group for P-gp revealed a 3.5 fold better prognosis compared with the low staining group (HR = 3.47, 95% CI = 1.62, 7.45; P = 0.0016). In conclusion, MDR1 gene/P-gp expression in pancreatic cancer without chemotherapy inversely correlates with biological aggressiveness and is an independent indicator of favorable prognosis.
|Number of pages||9|
|Journal||Japanese Journal of Cancer Research|
|Publication status||Published - 1996 Jun|
- MDR1 gene
- Pancreatic cancer
ASJC Scopus subject areas
- Cancer Research