| Summary: | <p>Abstract</p> <p>Background</p> <p>It is known that alpha-defensin expression is enhanced in colon cancer. However, the expression of human alpha defensin 6 (DEFA 6) in earlier stages, such as adenoma, has so far not yet been studied in a patient resolved manner.</p> <p>Methods</p> <p>By using quantitative Real Time-PCR, the gene expression pattern of <it>DEFA 1-3 </it>and <it>DEFA 6 </it>was analyzed in tissue of different stages of carcinogenesis, derived from colorectal cancer patients. In addition to paired normal and tumor tissue, matched normal near tumor and adenoma tissue samples were examined.</p> <p>Results</p> <p>The median gene expression of human defensin alpha 6 (<it>DEFA 6</it>) has been found to be moderately increased (~ 5 fold) in tumor samples derived from individuals with colorectal cancer (CRC) when compared to their normal counterparts. However, when the data were analyzed in a patient-wise manner, a large expression variation among individual patients is found, making the use of <it>DEFA 6 </it>for individual diagnosis of fully blown colon carcinoma difficult. Surprisingly, in adenoma the gene expression analysis revealed a 100 fold increased median expression of <it>DEFA 6 </it>relative to normal colon tissue. 13/18 samples had an individual overexpression of more than 60 fold in adenoma but only 3/17 in carcinoma. In each of the individual patients, at least either the adenoma or the carcinoma showed strong <it>DEFA 6 </it>overexpression.</p> <p>Conclusions</p> <p>We suggest that the expression of <it>DEFA 6 </it>preferably can be used as a potential diagnostic marker for adenoma and not as a marker for fully blown carcinoma. This is supported by the fact that <it>DEFA 6 </it>is a downstream target of the Wnt pathway, which is mutational active during the earliest stage of cancer development.</p>
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