To characterize molecular mechanism involved in pancreatic carcinogenesis, we analysed gene-expression profiles of 18 pancreatic tumors using a cDNA microarray representing 23,040 genes. As pancreatic ductal adenocarcinomas usually contain a low proportion of cancer cells in the tumor mass, we prepared 95% pure populations of pancreatic cancer cells by means of laser microbeam microdissection, and compared their expression profiles to those of similarly purified, normal pancreatic ductal cells. We identified 260 genes that were commonly upregulated and 346 genes that were downregulated in pancreatic cancer cells. Because of the high degree of purity in the cell populations, a large proportion of genes that we detected as upregulated or downregulated in pancreatic cancers were different from those reported in previous studies. Comparison of clinicopathological parameters with the expression profiles indicated that altered expression of 76 genes was associated with lymph-node metastasis and that of 168 genes with liver metastasis. In addition, expression levels of 30 genes were related to the recurrence of disease. These genome-wide expression profiles should provide useful information for finding candidate genes whose products might serve as specific tumor markers and/or as molecular targets for treatment of patients with pancreatic cancer.

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SSI clearly prolonged the hospital stay and increased medical costs. The numerical values revealed by this study reinforce the medical-economic importance of instigating preventive measures against SSI.

Under the current healthcare system in Japan, the development of SSI after abdominal surgery necessitates extension of hospitalization two-fold and increases the post-operative healthcare expenditure 2.5-fold. Development of SSI after cardiac surgery necessitates extension of hospitalization fourfold and increases the healthcare expenditure six-fold.

In view of the clinical variables obtained on POD3, such as amylase levels in drain effluent, body temperature, and leukocyte count, clinically relevant pancreas-related infections could be predicted well.