A novel aspartate protease gene, ALP56, is related to morphological features of colorectal adenomas.

Background And Aims: The recently identified aspartate protease gene ALP56 is up-regulated in human malignant tumors, including colorectal cancers, but the relationship remain unclear between ALP56 gene expression and clinicopathological findings, as well as when genetic alterations in ALP56 occur during the colorectal adenoma-carcinoma sequence. We therefore investigated expression of ALP56 mRNA in various human colorectal tissues.

Materials And Methods: We examined 18 colorectal adenomas 22 cancers, and 24 adjacent normal mucosal samples from patients undergoing conventional resection or endoscopic mucosal resection. Expression of ALP56 mRNA was determined by quantitative reverse-transcription polymerase chain reaction.

Results: Up-regulation of ALP56 gene transcription was observed in both adenomas and cancers compared to normal mucosa. ALP56 expression in exophytic adenomas was significantly greater than in flat adenomas.

Conclusion: ALP56 may contribute to colorectal adenoma formation and to an exophytic growth pattern in these adenomas.